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Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577a
PMCID: PMC5724663

Adolescent Scoliosis 1
A001: Radiographic Results of Selecting the Touched Vertebra as the Lowest Instrumented Vertebra in Lenke Type 1 (Main Thoracic) & Type 2 (Double Thoracic) Curves at a Minimum 5-year Follow-up

Abstract

Introduction:

A prior study showed the touched vertebra (TV), defined as the most cephalad thoracolumbar/lumbar vertebra “touched” by the center sacral vertical line (CSVL), as a potential landmark vertebra & recommended lowest instrumented vertebra (LIV) as well. We evaluated a large cohort of Lenke type 1 & 2 cases to determine if selecting the TV as the LIV will produce optimal positioning at a min. 5 yrs postoperative. Our hypothesis was that it would and that fusing short of the TV would lead to a suboptimal result.

Material and Methods:

299 pts with Lenke 1 (n = 207) or Lenke 2 (n = 92) AIS curves at a min. 5 yr f/u were evaluated. The TV was selected on the preoperative x-ray by 2 independent examiners & confirmed for agreement. The LIV selected was compared to the preoperative TV as well as the LIV-CSVL distance at min. 5 yr f/u. Comparison was made on the LIV-CSVL distance in pts fused short of the TV, to the TV or distal to the TV using standard statistical software.

Results:

When comparing the entire cohort, differences in 5 yr LIV-CSVL absolute values between the 3 groups approached, but did not reach, significance (P = .055). In a subanalysis of the lumbar A modifiers (n = 161), main effect ANOVA indicated a significant difference among the 3 groups (P = .002). Post hoc comparison revealed that pts fused short of the TV (TV-1) had significantly greater LIV-CSVL distance values than those fused to the TV (P = .006) & those fused distal to the TV (TV+1, P = .002). There was no significant difference among the 3 groups when looking at lumbar B (n = 76, p = 0.424) & lumbar C (n = 62, P = .326) modifiers.

Conclusion:

Selecting the touched vertebra (TV) as the LIV for Lenke type 1A & 2A curves produced optimal LIV positioning at a minimum 5 yrs postoperative, while fusing short of the TV showed statistically increased LIV- CSVL translation. Understanding & utilizing the TV rule assists the surgeon in proper LIV selection in Lenke type 1A & 2A curve patterns for AIS.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577b

A002: Shoulder Balance in Lenke Type 1 Scoliosis Treated by Convex Manipulation: The Role of Osteotomies

Abstract

Introduction:

Shoulder balance is important for adolescent idiopathic scoliosis, which affects the patient’s appearance and satisfaction after scoliosis surgery. We report perioperative and 3-year results in terms of deformity correction and shoulder balance in a consecutive series of patients treated by convex manipulation through an all-level pedicle screws convex instrumentation.

Material and Methods:

From January 2013 to January 2016 we surgical treated 42 consecutive patients (37 F, 5 M, mean age 13 years) affected by Lenke type 1 scoliosis. Mean preoperative Cobb angle was 56° ± 6°. Shoulder balance was evaluated by pre-operative measurement of clavicle angle and T1-tilt. We performed a posterior access only in all patients using polyaxial pedicle screws at each level on the convex side of the curve. Among this patients, we distinguished 2 groups: patients in which posterior column osteotomies (PCO) were performed at the apical level of scoliosis only on the convexity of the curve (10 patients), and patients in which PCO were not performed (32 patients). All the correction maneuvers were performed on the convex prebent rod. In all cases motor-evoked potentials monitoring was used. Mean follow-up time was 32 months.

Results:

The average percentage of coronal correction was 76 ± 5% (mean postoperative Cobb angle 15° ± 4°), with no neurological complications. Concerning the post-operative kyphosis, we observed a slight decrease of mean values compared to preoperative measurements (mean reduction of thoracic kyphosis 5° ± 2°). At 3-year follow-up no changes in coronal nor in sagittal plane were observed. Concerning post-operative shoulder balance, we reported a statistically significant change in clavicle angle and T1-tilt in patients operated with asymmetrical PCO respect to patients in which PCO were not performed.

Conclusion:

This case-series study shows the effectiveness and the safety of convex manipulation in Lenke type 1 scoliosis. The coronal correction obtained with this technique is comparable to that obtained with the traditional concave derotation. Concerning shoulder balance correction, PCO, providing a shortening and a higher mobilization of the convex side of the curve, allow a better management of the proximal thoracic spine and, consequently, a better restore of shoulder symmetry.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577c

A003: Sagittal Cervical Compensation in Adolescent Idiopathic Scoliosis

Abstract

Introduction:

The aim of this study is to analyse the sagittal alignment of cervical spine in surgically treated adolescent idiopathic scoliosis(AIS) and its association with alignment of thoracic and lumbar column.

Material and Method:

A retrospective review of clinical and radiological data from databases of two university hospital spine clinics was performed. 47 consecutive AIS patients were included in the study, the remainder were excluded due to poor quality Xrays where the CS was not properly visible, or previous surgery. Sagittal parameters were evaluated on AP an Lateral X-rays using software: C2-C7 lordosis, C2-C7 SVA, T4-T12 kyphosis, upper thoracic cobb angle, lower thoracic cobb angle, L1-S1 lordosis and Lenke type of scoliosis. These measurements were then evaluated for possible associations with patient age and with pre-existing measurements using t test.

Results:

There were 42 females and 5 males among retrospective databases; mean age at surgery was 15.21 ± 2.34 years. No significant differences in T1SS, C2-7 SVA, C2-7 Cobb angle, thoracic kyphosis were seen during the follow up. On the other hand, preoperative and postoperative measurements of L1-S1, upper thoracic and main thoracic angles showed significant differences.

Conclusion:

Patients with AIS appear to compensate for abnormal thoracic alignment with changes in cervical sagittal alignment. Significantly less cervical kyphosis was seen in Lenke 5 and 6, and greater cervical kyphosis in Lenke 1, 2, 3 curves. Overall the study group, cervical alignment showed no significant correlation with the Lenke types.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577d

A004: Intrathecal Morphine Reduce Blood Loss During Idiopathic Scoliosis Surgery

Abstract

Objective:

This retrospective study was designed to assess the impact of intrathecal morphine compared with no intrathecal morphine on blood loss during posterior spine instrumented fusion to correct pediatric idiopathic scoliosis.

Material-Method:

A retrospective study was done of the data and the anesthetic charts of 95 patients underwent scoliosis surgery between January 2008 and June 2016 by the same orthopedic surgeon. Forty patients were operated without intrathecal morphine (NITM) and 55 with intrathecal morphine (ITM). A statistical comparison has been done between the two groups of the blood loss, the number of patients received blood transfusions and the volume of the blood transfused.

Results:

Blood loss was significantly greater in NITM group with 2016.1 ± 857.3 ml instead of 725 ± 312.2 ml (P < .0001). All the patients (40 patients) of the NITM group received blood transfusions while only 13 patients (from 55 patients) of the ITM group needed blood transfusions. The volume of blood transfused per patient was significantly greater in the NITM group (726.3 ± 487.3 ml) than in the ITM group (295.4 ± 170.9 ml), (P < .0001).

Conclusions:

Our data are similar with previous published study and demonstrate that intrathecal morphine in pediatric surgical scoliosis correction decreases significantly the inta-operative blood loss and the number of the blood transfusions.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577e

A005: Spinal Growth in Patients with Juvenile Idiopathic Scoliosis Treated with Boston Brace

Abstract

Introduction:

In children with juvenile idiopathic scoliosis (JIS), the spinal deformity can have serious consequences for lung development and may reduce life expectancy. The treatment goal of JIS is to maximize growth of the spine and thorax by controlling the spinal deformity, while simultaneously preserving normal lung development. Bracing and growth-friendly spine surgery have been used to control the curve. However, growth-friendly implants usually requires multiple surgeries, is associated with complications and can decrease spinal growth. The effect of bracing on spinal growth is unknown. The aim of the study is to evaluate spinal growth in braced JIS patients.

Material and Methods:

38 female JIS patients were retrospectively selected from our database. These patients were diagnosed with JIS and were treated with brace during childhood. Three PA spine radiographs were selected: before start of bracing, after brace treatment and at final follow-up. Age, total length and duration of brace treatment were recorded. The following variables were measured on the radiographs using Surgimap: Cobb angle, T1-T12 length and T1-S1 length.

Results:

The average age of diagnosis was 7.1 years (1.5-9.5). Brace treatment was started at an average age of 11.3 years with a Risser of 0.5 and was stopped at an average age of 14.6 years with a Risser of 4.2. The brace was prescribed for a mean of 40 months. The Cobb angle of the main curve before and after bracing were 33° (20°-60°) and 31° (10°-63°) respectively. At skeletal maturity, 8 patients were treated surgically with a mean angle of 55° (44°-62°) before surgery. Patients not requiring surgical treatment had an mean angle of 28° (13°-53°) at final follow-up. Before treatment, mean T1-T12 length was 241 mm (147-297), T1-S1 length 385 mm (225-463) and total length 1528 mm (940-1790). After treatment, mean T1-T12 length was 279 mm (205-317), T1-S1 length 446 mm (334-518) and total length 1692 mm (1420-1935). And at last follow-up, mean T1-T12 length was 286 mm (240-328), T1-S1 length 458 mm (379-535) and total length 1711 mm (1545-1945). The total length gain from start brace to last follow-up was 43 mm (8-118) for T1-T12 length, 68 mm (6-200) for T1-S1 length and 141 mm (20-431) for total length. Spinal growth during brace treatment was 14.3 mm/year (T1-T12) and 23.3 mm/year (T1-S1).

Conclusions:

Brace treatment may be useful for managing JIS in 30 of 38 patients by preventing progression of the curve. The study is descriptive and provide an overview of spinal growth in patients with JIS treated with the Boston brace. Based on Dimeglio’s data, normal spinal growth is 1.1 cm/year (T1-T12) and 1.8 cm/year (T1-S1) between 10 years and skeletal maturity. The braced patients grew 1.4 cm/year (T1-T12) and 2.3 cm/year (T1-S1) during the treatment period indicating that bracing had no significant negative effect on longitudinal spinal growth.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577f

A006: Verticality Perception in Adolescents with Idiopathic Scoliosis

Abstract

Introduction:

Adolescent idiopathic scoliosis (AIS) is a three-dimensional spine deformation, whose aetiopathogenesis remains unclear. Current literature indicates a possible vestibular origin of AIS. A vestibular deficit may cause an asymmetrical contraction of the axial muscles, which, in turn, leads to a vertebrae malformation in a period of rapid spinal growth, where compensatory (proprioceptive) mechanisms are quite limited. One way to explore vestibular function is the subjective estimation of the gravitational vertical. Deviations or tilts of the perceived visual vertical are the most sensitive sign of a vestibular tone imbalance in roll and occur with lesions on peripheral or central vestibular pathways from the labyrinth to the vestibular cortex. In this study, we aimed to investigate and compare the contribution of different sensory modalities to the subjective estimation of the gravitational vertical between AIS patients and healthy individuals.

Material and Methods:

All study subjects (AIS Group, n = 10, age 11-16y, Cobb’s angle > 15o) and healthy age matched adolescents (control group, n = 10) performed a series of subjective internal estimation of verticality in two visual conditions (open/closed eyes) and using three different segments (hand, head and trunk). Specifically, they were asked to control the verticality of a visual rod (displayed on a large TV screen in front of them) using a joystick that was either hand-held [Subjective Visual Vertical (SVV) and Subjective Haptic Vertical (SHV) with open and closed eyes respectively] or attached to the trunk or head [Subjective Postural Vertical (SPV) The rod’s initial tilt position was set at 18o of tilt either clockwise or counterclockwise. An electromagnetic tracking sensor attached to the joystick or the trunk/head measured the rod’s actual deviation from the gravitational vertical in degrees (error).

Results:

A 2 (group) x2 (visual condition) x3 (segment) ANOVA revealed that the error in the subjective estimation of verticality was greater when the estimate was performed with closed eyes [clockwise: (F(1,18) = 45,67, P = .000); counterclockwise: (F(1,18) = 114.67, P = .000]. Moreover, a significant three-way interaction (counterclockwise direction: F(2,36) = 4.64, P = .016, h2 = .205) confirmed that differences among groups in verticality estimation were dependent on the visual condition and the segment used to perform the test. Post-hoc analysis revealed that AIS subjects had a greater error (deviation from the earth vertical) than controls when estimating verticality with the head and closed eyes (t(18) = −3.6, P = .002).

Conclusion:

Since head acceleration in the roll direction with closed eyes is mostly sensed by the semi-circular canals, these results suggest the presence of a vestibular tone imbalance in AIS participants. These findings may prove useful in the early diagnosis and prognosis definition of AIS.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577g

Cervical Laminoplasty
A007: Correlation between Posterior Migration of Spinal Cord and Cervical Spine Curvature after Cervical Laminoplasty

Abstract

Introduction:

Cervical laminoplasty is an effective procedure for decompressing multilevel spinal cord compression. Posterior compressive bone as well as hypertrophied ligamentum flavum is directly removed and dorsal migration of the spinal cord allows for indirect decompression of the anterior spinal cord. Spinal cord back shift has been considered the desired end point of posterior decompression procedures. However, a wide range of posterior spinal cord drift has been reported in the literature and reported data refer to different averages, such as that of each level for a given patient, or that of each single level, or the mean value of all patients. The aim of our study was to correlate the posterior migration of the spinal cord after extensive laminoplasty to the cervical spine curvature.

Materials and Methods:

Twenty-nine patients (15 men and 14 women) who underwent bilateral open-door laminoplasty between C3 and C7 levels were included in this study. The average age at operation was 64 years (range, 43-87 years). All patients presented with symptoms of neural compression and magnetic resonance imaging (MRI) findings were consistent with CSM. All patients underwent plain radiographs and MRI pre- and post-operatively. The distance from the posterior edge of each vertebral body to the anterior edge of the spinal cord was measured on sagittal MRI, in order not to be influenced by the postoperative cord expansion. Cervical sagittal alignment was assessed from pre-operative lateral cervical radiographs and classified as lordosis, kyphosis, straight or S-shaped.

Results:

The posterior spinal cord shift ranged from a maximum of 6.2 mm to a minimum of -0.1 mm, with an average of 1.8 mm. The peak shift was 2.8 mm at C5. The mean posterior spinal cord shifts in the different neck alignment groups were 1.8 mm for the lordosis group, 1.5 mm in the straight-neck group, 1.5 mm in the kyphosis group and 2.4 mm in the S-shaped group. The peak shift was located at C5 in the lordosis group (2.8 mm) and in the straight-neck group (3.1 mm), C7 in the kyphosis group (2.8 mm) and C6 in the S-shaped group (3.9 mm). The minimal posterior spinal cord shift was located at C7 in the lordosis group (1.4 mm) and at C3 in the S-shaped group (1.7 mm), in the straight-neck group (0.4 mm) and in the kyphosis group (0.4 mm). In the lordosis and the S-shaped groups we observed the greatest backward movement in the middle of the cervical spine, at the point of maximum concavity, like a bowstring.

Conclusions:

The preoperative lordotic alignment of the cervical spine influences the degree of posterior movement of the spinal cord after extended laminoplasty. Cervical lordosis allows a maximal spinal cord back shift. Moreover, the final spinal cord position is different according to the preoperative alignment of the spine, with a bowstring effect in lordosis and S-shaped cervical spines. Finally, the risk of C5 palsy should be anticipated in lordotic and straight spines where the peak shift is located at C5.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577h

A008: C4/5 Foraminal Stenosis Predicts C5 Palsy after Expansive Open-Door Laminoplasty

Abstract

Introduction:

Laminoplasty is frequently performed in cervical myelopathy patients, but can lead to unexpected postoperative C5 palsy. Although several studies have examined the pathogenesis and prevention of postoperative C5 palsy, many controversies remain and some radiological findings identified as risk factors were not correlated with our outcomes.

Material and Methods:

This study reviewed 116 patients who underwent open-door laminoplasty for cervical spondylotic myelopathy between January 2014 and April 2016. All operations were performed by one surgeon. C5 palsy was defined as weakness [change in manual muscle testing (MMT) score of 1 or 2] of the deltoid muscle. The patients were divided into groups that developed or did not develop C5 palsy. We evaluated the incidence of C5 palsy, the preoperative C2–7 Cobb angle, and Pavlov ratio at the C4/C5 level using simple cervical lateral radiographs. Furthermore, by using computed tomography (CT), we evaluated the existence of an ossified posterior longitudinal ligament (OPLL), the transverse diameter of the C4/5 foramen, and increases in the anteroposterior (AP) diameter of the spinal canal at the C4/5 levels after surgery. To assess the correlation between C4/5 foraminal stenosis and C5 palsy, we subdivided the C4/5 foramina into two groups: 8 with C5 palsy and 192 without C5 palsy. Finally, a high signal intensity on T2-weighted images of the cervical spinal cord preoperatively was noted.

Results:

Of the 116 patients, 16 cases were excluded and 100 cases were analyzed; postoperative C5 palsy occurred in 8 patients (8%). There were no significant differences between the two groups in sex, age, the presence of an OPLL, or preoperative high signal intensity on T2-weighted images of the cervical spinal cord. The preoperative C2–7 Cobb angle, Pavlov ratio at the C4/C5 level, and increase in AP diameter of the spinal canal at the C4/C5 level were not significantly related to postoperative C5 palsy. However, the average diameter of the C4/5 foramen of the affected side was 2.51 mm, while that of the unaffected side was 3.88 mm (P = .004); a diameter of the C4/5 foramen of less than 2 mm was significantly related to C5 palsy in the binary logistic regression test (P = .000). In this study, a smaller diameter of the C4/5 foramen was the only factor significantly correlated with C5 palsy after laminoplasty.

Conclusion:

C4/5 foraminal stenosis is one of the best predictors of C5 palsy, which might be related to ischemic/reperfusion injury of the C5 root nerve after laminoplasty. This should be examined further in prospective comparative or basic experimental studies.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577i

A009: A MRI Characterization of the Dorsal Cervical Cord Migration Behaviour in Laminectomy versus Hybrid Open-Door Laminoplasty

Abstract

Introduction:

Posterior cervical approach has become the treatment of choice for cervical spinal cord compression related pathology in more than three vertebral levels. Previous studies compared clinical outcomes of cervical laminoplasty with laminectomy and have reported inconsistent findings. There has been a recent development of a hybrid laminoplasty approach (C3 dome osteotomy, C4-6 laminoplasty and upper C7 laminectomy) with muscle sparing techniques. To the best of the authors’ knowledge, there are no studies comparing the results of hybrid laminoplasty with laminectomy with fusion. The aim of this study is to compare and evaluate the surgical outcomes of hybrid laminoplasty with laminectomy with fusion in terms of radiological findings.

Material and Methods:

A retrospective review of 42 consecutive patients, who had undergone cervical laminectomy with fusion (LF) or hybrid laminoplasty (HLP) by a single surgeon, was performed. Surgical outcomes were assessed and Image J software was used to evaluate pre- and post-operative Magnetic Resonance Imaging (MRI) scans for posterior cord migration and dural sac expansion of the two groups (LF and HLP). Radiological data captured was analysed using SPSS software.

Results:

36 cases with pre- and post-op MRI were included in the study. Average follow up duration was 1.5 years. 16 patients had laminectomy with fusion (LF) and 20 had hybrid laminoplasty (HLP). There were no statistically significant differences between the LF and HLP group in terms of age, gender, follow-up duration, pre-operative diagnosis and pre-operative JOA score. There were however 2 cases of post-operative C5 palsy in LF compared to none in HLP. A trend is shown with the laminectomy with fusion (LF) group displaying greater dorsal cord migration than the hybrid laminoplasty (HLP) group at all levels from C2-T1. Comparing between cervical spinal levels, the extent of dorsal cord migration is shown to be greatest at the level of C4-5 in LF (1.94 ± 1.60 mm, P = .01) and C5-6 in HLP (1.71 ± 1.17 mm, P = 0.00). In comparing patients with post-operative C5 palsy with those who did not acquire C5 palsy, dorsal migration was found to be significantly greater in the C5 palsy group at the levels of C4-5 (4.38 ± 0.50 mm vs 1.64 ± 1.04 mm, P = .02), C5-6 (4.97 ± 0.99 mm vs 1.57 ± 1.29 mm, P = .02), C6-7 (4.20 ± 0.83 mm vs 0.77 ± 1.09 mm, P = .02) and C7-T1 (1.74 ± 0.96 mm vs 0.01 ± 1.33 mm, P = .045) as compared to the non-C5 palsy group.

Conclusion:

This is the first MRI study to prove that there is a trend towards greater posterior cord migration in laminectomy with fusion compared to hybrid laminoplasty in patients presenting with cervical myelopathy. A statistically significant greater dorsal cord migration was found at C4-5 spinal level in patients with C5 palsy.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577j

A010: A Metanalysis of Cervical Laminoplasty Techniques: Are Mini-Plates Superior?

Abstract

Introduction:

Laminoplasty first described by Tsuji in 1982 as an alternative to laminectomy as the treatment for cervical spondylotic myelopathy CSM. The technique was developed in an effort to eliminate the development of instability and kyphosis following laminectomy while achieving minimal reduction in cervical range of movement (ROM) compare to fusion. In the late 1990’s, spinal surgeons experimented the use of maxillofacial fixation plates as an alternative to sutures, anchors and local spinous process auto-grafts to provide a more rigid and lasting fixation of laminoplasty. This eventually led to the advent of laminoplasty mini-plates, which are currently used.

Objective:

Is to compare laminoplasty with plate and without plate techniques in terms of functional outcome results.

Material and Methods:

A qualitative and quantitative analysis was performed to evaluate the current available literatures in an attempt to justify the use of plate in laminoplasty. Given the relatively high costs associated with the use of these plates and limited available data in the literatures about laminoplasty techniques and outcome.

Results:

The principal finding of this study was that there was no statistically significant difference in clinical outcome between the two different techniques of Laminoplasty.

Conclusion:

There is no enough evidence in the Literatures to support one technique over the other and hence there is no evidence to support change in practice (using or not using the plate in laminoplasty). Randomized control trial will give better comparison between the two groups.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577k

A011: Comparison between Radiological and Clinical Outcomes of Laminoplasty with a Titanium Miniplate for Cervical Myelopathy

Abstract

Introduction:

Laminoplasty is a surgical procedure frequently performed for cervical myelopathy. We investigated correlations between changes in the anteroposterior diameter (APD) of the spinal canal, spinal canal area (SCA), and laminar angle (LA) and clinical outcomes of laminoplasty.

Material and Methods:

Of the 204 cervical myelopathy patients who underwent laminoplasty from July 2010 to May 2015, 49 patients who were evaluated with pre- and postoperative computed tomography of the cervical vertebrae were included. The average age of the patients was 60.4 years (range, 31–82 years), and the average duration of follow-up was 31.6 months (range, 9–68 months). Changes in the APD and SCA were measured at the middle of the vertebral body. Changes in LA were measured where both pedicles were clearly visible. Clinical outcomes were assessed using the Japanese Orthopedic Association (JOA) score and visual analog scale score for pain preoperatively (1 day before surgery) and postoperatively (last outpatient visit) and examining postoperative complications.

Results:

The APD showed an average of 54.7% increase from 11.5 to 17.8 mm. The SCA showed an average of 57.7% increase from 225.9 to 356.3 mm2. The LA increased from 34.2° preoperatively to 71.9° postoperatively. The JOA score increased from an average of 9.1 preoperatively to 13.4 postoperatively. Three patients were found to have hinge fractures during surgery. Postoperative complications, including two cases of C5 palsy, were recorded. The correlation coefficient between the LA change and JOA score improvement was −0.449 (P < .05). Patients with a <33.8° (25%) increase in the LA showed the most significant clinical improvement.

Conclusion:

Patients with a <33.8° (25%) change in the LA after laminoplasty with a titanium miniplate showed the most significant clinical improvement. Thus, LA changes can be useful in predicting the clinical outcome of laminoplasty.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577l

A012: Open-Door Laminoplasty for Multilevel Cervical Spondylotic Myelopathy and OPLL using Titanium Reconstruction Miniplate and Screws

Abstract

Introduction:

To review outcome of 25 patients who underwent open-door cervical Laminoplasty for multilevel cervical spondylotic myelopathy and OPLL using titanium reconstruction miniplate and screws.

Material and Methods:

Records of 18 men and 7 women aged 35 to 78 (mean, 62.6) years, who underwent open-door cervical Laminoplasty for myelopathy using titanium reconstruction miniplate alone were reviewed. 4 patients had 5 levels of decompression (C3-C7), 21 patients had 4 levels of decompression (C3-C6). Foraminotomies were performed in 3 cases (12%). A total of 104 laminae were opened, all of them were fixed with a titanium miniplate. In 21 patients, a 20-hole titanium miniplate bent to the contour of a lamina was used and fixed into 4 laminae and 4 patients fixed in 5 laminae levels. In most patients, screw fixation was unicortical, and no spacer or bone graft was used. Demographic data and surgical data including estimated blood loss (EBL), length of surgery, number of laminoplasty levels, complications and length of hospitalization were collected. Clinical outcomes were assessed with neck pain score using visual analog scale, neck disability index. Nurick’s grading was used for quantifying the neurological deficits and outcome analysis was done using Odom’s criteria.

Results:

The mean follow-up duration was 1.8 (range: 1–5) years. Diagnosis was cervical spondylotic myelopathy (n = 20), ossification of the posterior longitudinal ligament (OPLL, n = 5). Mean estimated blood loss (EBL) was 120 ml (range: 50-200), mean surgery time was 153 min (range: 75-240). Following Nurick`s scale, 23 patients (92%) improved, 2 (08%) had the same Nurick grade. No intraoperative complications were noted and average hospital stay was 6.12 days (range: 5 to 9). Significance improvements in overall NDI scores occurred at 1 year follow up (P < .002). Radiographic evaluation showed an increase in the mean sagittal diameter from 12.2 mm at pre-treatment to 18.3 mm post-surgery. 2 patients developed transient C5 palsy, presenting as shoulder abduction weakness.

Conclusion:

Open-door Laminoplasty technique using titanium reconstruction miniplate and screws is safe, easy and achieves a good canal expansion and neurological recovery and can be used as an alternative treatment for cases of multilevel cervical spondylitic myelopathy and OPLL patients without instability.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577m

Lumbar Adjacent Segment Pathology
A013: Comparative Analysis of Risk Factors for Adjacent Segment Disease after Lumbar Spinal Fusion: More Than 10 Year-Follow-up

Abstract

Introduction:

There are many concerns about ASD after lumbar spinal fusion using pedicle screws. There are many studies about the causes that is natural degenerative change or risk factors. It was to analyze risk factors for adjacent segment disease(ASD), by comparing patients occurred ASD with patients followed more than 10 years after lumbar spinal fusion with pedicle screw fixation for degenerative lumbar spinal disease.

Materials and Methods:

From August 1988 to December 2005, 581 patients underwent lumbar spinal fusion of 3 and less segment to treat degenerative lumbar disease. Among them, 180 patients underwent revision surgery for ASD or followed more than 10 years were included in this study. Average The mean age at the initial operation was 53.6 years old and the mean follow-up period was 160.6 months. Gender, age, residence, preoperative diagnosis, fusion method, number of fused segments, whether laminectomy of adjacent segments, preoperative degree of disc degeneration of adjacent segments in MRI, wether adjacent segments included L4-5 or L5-S1, and radiological measurements were analyzed. In radiological measurement, pre-& post-operative lumbar lordotic angle (LLA), correction of LLA, post-operative fusion segment lordotic angle(FSLA) per level were estimated. Statistical univariate analysis was performed with the Chi-square test and multivariate logistic regression analysis was done by using SPSS 14.0. (P < .05).

Results:

There were 40 patients with revision surgery due to ASD. Seven patients were operated by decompression or discectomy and 33 patients needed additional fusion. In univatiate analysis, the frequency of ASD was significantly high in cases that age was more than 65 years old (P = .002), laminectomy of adjacent segment was performed (P = .002), preoperative disc degeneration of adjacent segments in MRI was present(p = 0.001) and post-operative FSLA per level was <16° (P = .024). In multivariate logistic regression analysis, the frequency of ASD was significantly high in case that age was more than 65 years old (P = .015, odd ratio = 3.106), laminectomy of adjacent segment was performed (P = .012, odd ratio = 5.044) and preoperative disc degeneration of adjacent segments in MRI was present (P = .022, odd ratio = 3.008).

Conclusions:

We analyzed risk factors for ASD, by comparing patients occurred ASD with patients followed more than 10 years after lumbar spinal fusion for degenerative lumbar spinal disease. Development of ASD was affected that age was more than 65 years old at initial operation, laminectomy of adjacent segment was performed and preoperative disc degeneration of adjacent segments in MRI was present. In case of old age and patients existed preoperative degenerative change of adjacent segment, careful decision should be considered to carry out lumbar spinal fusion.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577n

A014: Incidence of Adjacent Segment Disease following Posterior Lumbar Interbody Fusion Vs Postero-lateral Fusion: A Snapshot with 5 Years Follow up

Abstract

Introduction:

One of the major concerns after lumbar fusion surgery is the risk of developing adjacent segment disease (ASD). Both Posterior lumbar interbody fusion (PLIF) and posterolateral fusion (PLF) have been widely used by surgeons to address degenerative lumbar disease. However, the risk factors for developing of ASD are not clear. Some studies suggested that there is a higher rate of ASD with interbody fusion due to a more solid fusion, having a more profound effect on the caudal adjacent segment. In this study, we looked at our cohort of patients to investigate this further and establish other risk factors.

Materials and Methods:

We retrospectively reviewed our spinal unit data base to identify all patients who underwent posterior lumbar interbody fusion (PLIF) and Posterolateral lumbar fusion (PLF) over the last 5 years. 50 Patients of each group were randomly and blindly selected. Those with adjacent segment disease were identified. Co-morbidities, demographics, visual analogue scores preoperatively, then yearly, for the duration of five years were analysed. X-rays and CT scans were analysed and reviewed by 2 independent reviewers to assess the pelvic incidence change and sacral slope change.

Results:

All procedures were done by 3 spinal surgeons who use the same techniques and instrumentation. The difference of incidence of adjacent segment disease between the two groups was statistically insignificant. Both groups had comparative pre-operative co- morbidities; including smoking, diabetes, hypertension, obesity and steroid use. Both groups had similar socio-economic back grounds. X-rays and CT scans reviews showed no significant difference when assessing the pelvic incidence and sacral slope change (P < .001) with good inter-observer reliability (kappa 0.95).

Conclusion:

We concluded that smoking, diabetes, hypertension, obesity and steroid use are all risk factors for developing ASD. The incidence of ASD seems to be higher in younger patients with high physical activity. The choice of surgery; PLIF or PLF, does not affect the incidence of ASD.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577o

A015: Paraspinal Muscle, Facet Joint, and Disc Problems: Risk Factors for Adjacent Segment Degeneration after Lumbar Fusion

Abstract

Introduction:

Adjacent segment degeneration (ASD) is one of the major complications after lumbar fusion. Several studies have evaluated the risk factors of ASD. Although the paraspinal muscles play an important role in spine stability, no study has assessed the relationship between paraspinal muscle atrophy and the incidence of ASD after lumbar fusion. In the present study, we aimed to verify the known risk factors of ASD, such as body mass index (BMI), preoperative adjacent facet joint degeneration, and disc degeneration, and to assess the relationship between paraspinal muscle atrophy and ASD.

Material and Methods:

This is a retrospective 1:1 pair analysis matched by age, sex, fusion level, and follow-up period. Among the 510 patients who underwent posterior lumbar fusion for degenerative lumbar disease between January 2009 and October 2009, a total of 50 patients with ASD after surgery were selected. Another group of 50 matched patients with degenerative lumbar disease without ASD after spinal fusion were selected as the control group. Each patient in the ASD group was matched with a control patient according to age, sex, fusion level, and follow up period.The risk factors considered were higher BMI, preoperative adjacent segment disc and facet degeneration, and preoperative paraspinal muscle atrophy and fatty degeneration. The radiographic data were compared between the ASD and control groups to determine the predictive factors of ASD after posterior lumbar fusion by using logistic regression analysis. The study was not externally funded.

Results:

Multivariate logistic regression analysis indicated that higher BMI (odds ratio [OR]: 1.353, P = .008), preoperative facet degeneration on computed tomography examination (OR: 3.075, P = .011), disc degeneration on magnetic resonance imaging (MRI) (OR: 2.783, P = .003), fatty degeneration (OR: 1.080, P = .044), and a smaller relative CSA of the paraspinal muscle preoperatively (OR: 0.083, P = .003) were significant factors for predicting the development of ASD.

Conclusion:

The occurrence of radiological ASD is most likely multifactorial, and is associated with a higher BMI, preexisting facet and disc degeneration on preoperative examination, and a smaller preoperative relative CSA of the paraspinal muscle on MRI.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577p

A016: Minimally Invasive PLIF Did Not Have Advantage Over Conventional PLIF in the Incidence of Adjacent Segment Pathology

Abstract

Introduction:

Nowadays, adjacent segment pathology (ASP) is one of the problematic complications after posterior lumbar interbody fusion (PLIF). We need to seek the effective methods to decrease the incidence of symptomatic ASP and as a result to decrease the revision surgery. Minimum invasive PLIF (MI-PLIF) is one of the good candidates. Purpose of this study is to investigate whether MI-PLIF surgery could decrease the incidence of symptomatic ASP.

Material and Methods:

At our hospital 467 patients had PLIF between 2005 and 2010. Eligible patients were with single PLIF as an initial lumbar operation. Out of 467, 326 patients with revision surgery, systemic disease, additional decompression at the other segment, and isthmic spondylolisthesis were excluded. Thirty one patients did not satisfy 5-year follow up. Finally, 101 patients were (age; median 65, 37 male and 64 female) included in this study. Follow-up rate was 76%. Forty two patients had PLIF with conventional pedicle screw (C-PS), 33 with percutaneous pedicle screw (P-PS), 26 had stand-alone PLIF (SA). The endpoint was history of the symptomatic ASP at 5 years after operation. Symptomatic ASP was defined to be the pathology with the following three conditions. First, symptom before operation had disappeared or almost completely alleviated postoperatively. Secondly, new symptom had emerged at least three months after operation. Thirdly, the newly emerged symptom was considered to be owing to the pathology confirmed on magnetic resonance imaging(MRI).

Results:

Of 101 patients, 2 patients in SA group had reoperation at index level by 2 years. Two patients (2%) had reoperation at the adjacent segment by 2 years, and 9 patients (9%) by 5 years. The incidence of the symptomatic ASP was 24% in the C-PS group, 24% in the P-PS group, and 21% in the SA group. There was no significant difference with a small sized effect between the C-PS group and P-PS group (P = .9652, r = .01) nor between C-PS group and SA group (P = .7814, r = .07).

Conclusion:

In our study minimally invasive PLIF did not have advantage over conventional PLIF in the incidence of adjacent segment pathology.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577q

A017: Lumbar Fusion with Topping Off: A Failed Implant

Abstract

Introduction:

The lumbar spinal fusion is an established procedure for the treatment of many degenerative diseases of the lumbar spine and spondylolisthesis. However the development of adjacent-level degeneration has been described in many studies as late effect after lumbar spine fusion. The hybrid system topping off was invented to prevent the manifestation of the adjacent-level degeneration. This system includes a rigid spondylodesis and a flexible instrumentation of the adjacent-level. Purpose of this study is the assessment of clinical and radiological outcome.

Material and Methods:

In this prognostic prospective study have been patients included with a degenerative disease of the lumbar spine or spondylolisthesis with an indication for a lumbar fusion and additionally radiological signs of degeneration in the adjacent segment without instability (Pfirrmann Grad 2-4). Exclusion criteria were previous surgery of the lumbar spine and no disc degeneration in the MRI in the adjacent segment. All patients were treated with a monosegmental lumbar interbody fusion and dynamic Stabilization (topping off) of the cranial adjacent level (CD HORIZON BalanC™ rod System Fa. Medtronic plc, Dublin, Irland). The patients were subjected to clinical examination and radiographs pre-operatively and one year after the operation. The assessment of the clinical data has been obtained on the basis of the German spine register using the COMI score and VAS score for back- and leg-pain. The statistical program SPSS (Version 22.76 Chicago, IL, USA) was used for the evaluation of the data.

Results:

In the study have been 21 patients (5 male and 16 female) included. The average age of the patients was 58.9 ± 10.8 (min: 41, max: 78) years old. The average COMI score pre-operatively was 9.0 ± 0.9 (min: 6.7, max: 10.0). In the one-year-follow-up the average COMI score was 4.3 ± 2.4 (min: 0.0, max: 7.5). The results prove a significant reduction of the COMI score in the one-year-follow-up (P = .000). The average pre-operatively VAS was for back-pain 7.6 ± 2.4 (min: 0, max: 10) and for leg-pain 6.9 ± 2.9 (min: 0, max: 10). In the one-year-follow-up the VAS for back-pain was 4.3 ± 2.4 (min: 0, max: 8) and for leg-pain 2.3 ± 3.1 (min: 0, max: 8). Both VAS back- and leg-pain showed a significant reduction in the 1-year follow-up (P = .000). No radiological signs for adjacent-level degeneration have been observed in the one-year-follow-up. A fatigue fracture of the dynamic topping off material was verified in 4 cases (3 female and 1 male) during the follow-up.

Conclusion:

Biomechanical studies report about reduced stress forces to the adjacent-level after lumbar spinal fusions with the topping off system. However it is being implied that the topping off segment is with a high rigidity combined. Moreover the instrumentation of an additional segment is associated to higher operation morbidity. Our results demonstrate a significant improvement of the clinical outcome and reduction of the pain after lumbar spinal fusion with topping off, one year after the procedure. Our results are similar to standard lumbar fusion according to the literature one year after the operation. Due to the high rate of implant failure this implant is not being used anymore in our clinic.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577r

A018: Spino-Pelvic Malalignment In Adjacent Segment Disease Developing After Lumbar Fusion

Abstract

Introduction:

Spinal segment arthrodesis has become a widely accepted treatment for degenerative disorders of the lumbar spine. For today rigid internal fixation with 360° fusion has been viewed as the gold standard for spine stabilizing surgery. However spinal fusion alters the normal biomechanics of the spine and eliminates mobile segments causing overload of adjacent segments. At the same time many patients with degenerative disorders have abnormalities of spino-pelvic parameters, which remain postop. Thus, spinal fusion, according to some authors can accelerate the degeneration of adjacent segments, especially under unfavorable biomechanics of the spine.

Material and Methods:

This retrospective study evaluated 76 patients underwent 360° short fusion lumbar surgery (one and two levels) from 2008 to 2013 for the treatment of degenerative conditions of the lumbar spine. The patients were divided into two groups depending on the presence of symptomatic ASD: first group include 36 patients with symptomatic ASD during 3 years postop, second (control) group include 40 patients with no signs of symptomatic adjacent segment disease. There were 66% females. Mean age of 54 years (range 21-76). Mean follow-up of 4 years (3-7 years). Long cassette standing anteroposterior and lateral radiographs were performed on the preoperative, postoperative and follow-up visits. In all cases we studied preop, postop, and f/up sagittal plane alignment according to Schwab sagittal modifiers.

Results:

In the I group symptomatic ASD was found in 14 cases (38.9%) during 1 year follow-up. There were 6 cases (42.9%) with sagittal imbalance and 11 cases (78.6%) with the difference between pelvic incidence and lumbar lordosis (PI-LL) more than 11°. Summary after 3 years f/up in I group sagittal imbalance was diagnosed in 23 cases (63.9%), in 26 patients (72.2%) PI-LL was above or equal to 11°. Average postop SVA in the I group was + 6.2 cm, average PI-LL mismatch was 13.2°. 86% of the I group patients required revision surgery. In the II group at 3 year f/up sagittal imbalance was identified in 11 patients (27.5%) with average SVA + 2,8 cm. PI-LL above or equal to 11° was found in 10 cases (25%), average value for the II group patients was 8.1°.

Conclusion:

Patients with spino-pelvic alignment disturbances such as sagittal imbalance and PI-LL mismatch have statistically significant increasing risks of developing ASD because of overloading the adjacent segments under unfavorable biomechanics of the spine.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577s

Minimally Invasive Spine Surgery Lumbar
A019: Long Term Fusion Rates and Predictors for Reoperation in Patients with and without Preoperative Degenerative Lumbar Spondylolisthesis following Minimally Invasive Decompression for Lumbar Spinal Stenosis

Abstract

Introduction:

Minimally invasive decompression (MID) is an effective and safe procedure for lumbar spinal stenosis (LSS). In short-to-moderate term follow-up studies, (ie, <4-5 years) fusion rates have been shown to be lower with similar functional improvement compared to conventional open laminectomy. However, long term follow-up data is still missing. The primary objective of this retrospective cohort study was to evaluate predictors and long-term rates for reoperation in patients with LSS who underwent a MID, stratified for degenerative lumbar spondylolisthesis (DLS).

Material and Methods:

All consecutive patients with LSS with and without grade 1 DLS who had undergone MID between 2002 and 2011 were included in this analysis. The same technique was utilized by the senior author for all patients with neurogenic claudication/mechanical radiculopathy (ie, leg-dominant symptoms that were relieved by postural change and/or rest), no (or tolerable) mechanical back pain, and those with up to a 25% (grade I) spondylolisthesis, and no obvious dynamic instability on imaging. Radiographic dynamic instability was defined as an increase in spondylolisthesis by 4–5 mm or more demonstrated on supine to standing or flexion-extension imaging. Demographic, perioperative, and radiographic data were collected. Reoperation rates defined as any operation on the same or adjacent level were assessed. Revision decompression alone was considered if the aforementioned clinical and radiographic criteria were met, otherwise patient underwent a minimally invasive posterior fusion at revision. Clinical outcome was evaluated using the Oswestry Disability Index (ODI) and visual analog scale (VAS) scores.

Results:

Two-hundred forty-seven patients (mean age 66 years [20 − 88] at the time of the initial surgery) were included. The majority of patients (68.7%) underwent one level decompression. The most common decompressed level was L4-5 (47.2%). Preoperative spondylolisthesis at the level of spinal stenosis was present in 56.9%. Mean follow-up period was 8.2 years [5.0 −14.9]. The overall reoperation rate was 15.8% of which a fusion rate of 6.9% (4.1% vs. 2.8% in patients with and without spondylolisthesis, P = .546). The mean time to reoperation in patients with and without spondylolisthesis was 3.9 years [95%CI 1.8 − 6.0] and 2.8 years [95%CI 1.3 − 4.2], respectively for decompression only, and 3.1 years [95%CI 1.0 − 5.3] and 3.1 years [95%CI 1.1 − 5.1], respectively for fusion. At the 5-years follow-up point, no significant difference in the mean improvement of the ODI, VAS leg, and VAS back was observed in patients with and without spondylolisthesis. Logistic regression stratified for spondylolisthesis showed none of the investigated variables (age, gender, Body mass index, level or number of decompression, pelvic incidence, lumbar lordosis, facet angle, baseline VAS leg, VAS back and ODI) were predictive for overall reoperation or fusion at revision.

Conclusions:

Minimally invasive decompression is an effective and durable procedure for the treatment of LSS with or without stable DLS with similar reoperation rates compared to historical data. Using the abovementioned criteria, there were no independent predictors of reoperation following MID in stable DLS.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577t

A020: Minimally Invasive Transforaminal Lumbar Interbody Fusion with Intraoperative CT-Based Spinal Navigation: A Prospective Cohort of 40 Cases

Abstract

Introduction:

Minimally invasive transforaminal interbody fusion is nowadays a very popular technique. Potential advantages include reduced blood loss, shorter length of stay, and less soft-tissue trauma. Potential disadvantages include increased radiation exposure, longer operative times, and higher risk of screw malpositioning related to a inadequate visualization of anatomical landmarks. Spinal navigation could theoretically improve results with this technique, increasing accuracy during percutaneous screw positioning, decreasing operative time and radiation exposure for both surgeons and patients. We report results on a cohort of 40 operated patients, where we performed mini-open transforaminal interbody fusion (TLIF) at lumbar levels using spinal navigation coupled with an intraoperative mobile CT (iCT-AIRO®), without any use of fluoroscopy, except for the final control of cage position at interbody level.

Material and Methods:

Series includes 40 cases submitted to mini-open TLIF with 22 mm tubular retractors. All patients were affected by a degenerative disease of the spine, at one or two levels, with monolateral radicular pain. In every case decompression and cage positioning were performed without complications through tubular retractor. Screws were positioned percutaneously, before decompression and cage positioning, using iCT-based spinal navigation, without any use of fluoroscopy. Screw position was checked immediately after positioning.

Results:

There were 26 men and 14 women, with a mean age of 60 years (36-84). Thirty-six patients were operated by the same surgeon (PS). Six patients underwent a 2-level procedure. Mean follow-up was 10.5 months. We did not observe any neurological complications. Position of screws was optimal in every case, without any screw repositioning during surgery. Mean duration of surgery was 229 minutes. Surgical times reduced significantly in recent operated cases. No patient was reoperated during follow-up. At radiological analysis, 98% of screws were correctly placed in the pedicle (Heary grade 1). No screw was graded 4 or 5. Mean effective dose for patient was under 15 mSV, and not significantly higher than our previous experience with another imaging method (O-arm). This dose compared very favourably with reported dose for fluoroscopic assisted mini-TLIF.1 Mean number of intraoperative scans was 2.

Conclusion:

In a recent paper, Ruatti et al.2 showed a rate of malpositioned screws higher than 20% using spinal navigation for percutaneous screws. This rate was significantly lower with open technique. Use of spinal navigation coupled with an intraoperative CT significantly augmented, in our experience, accuracy in percutaneous screw positioning, compared with spinal navigation associated with a cone-beam CT (O-arm) or with traditional technique with fluoroscopic control. Reasons for this improvement are different, mostly related with a more stable positioning of the reference star on the iliac crest, and with a better quality of intraoperative imaging. In our series, there was significantly less radiation exposure for the surgical team. Surgical times were significantly higher than traditional open technique without navigation.

References

1. Bindal, R. et al. Surgeon and patient radiation exposure in minimally invasive transforaminal interbody fusion. JNS Spine 9;570-573, 2008.

2. Ruatti, S. et al. Interest of intra-operative 3D imaging in spine surgery: a prospective randomized study. Eur. Spine J. (2015). doi:10.1007/s00586-015-4141-5.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577u

A021: Clinical and Radiological Outcomes of InterFuse-S, A New Modular PLIF, in Patients with Lumbar Disc Herniation

Abstract

Introduction:

One concern about posterolateral interbody fusion (PLIF) implants is the insufficient primary stability that impacts negatively on fusion rate, increases the chance of subsidence with loss of segmental lordosis. To avoid posterior migration, PLIF also needs to be supplemented with pedicle screws increasing the costs and the surgical complications. Recently, a novel modular PLIF assembled intraoperatively by a rail-and-slot design into the disc space, InterFuse STM, has become available. It can be inserted through the small annulus opening of a classical microdiscectomy, without further facet joint resection preventing the potential for post-operative instability. Once implanted, it provides the largest surface area for load-sharing even when compared to anteriorly inserted cages. The aim of this study is to evaluate the feasibility, safety and outcomes using stand-alone Interfuse-S. We hypothesized that the increased surface area can adequately promote fusion, segmental lordosis with good clinical results obviating the need to add transpedicular screws.

Material and Methods:

Ten consecutive patients, 5 males and 5 females, with extruded lumbar disc herniation underwent PLIF with InterFuse STM. No pedicle screw fixation was performed. Median age was 37.6 years (range 22-46). All patients underwent a single–level procedure (8 patients at L5-S1, 2 patient at L4-5). The indications were extruded lumbar disc herniation.

Results:

No surgical complications or neurological deficits were noted, as reflected in a mean hospitalization of 2.3 days. At 12 months FU, mean back VAS decreased from 7 to 2 (P < .01) and leg pain resolved in all patients (P < .01). A 100% rate of successful fusion was observed. No cases of implant subsidence or breakage were found. Segmental lordosis was observed in all patients. There was one case of posterior migration that conducted to revision surgery in an obese and heavy lifter patient.

Conclusions:

Stand-alone PLIF with InterFuse STM is a feasible and safe technique compared to conventional PLIF or TLIF in young patients with lumbar disc herniation, without compromising clinical and radiological outcomes. With a less invasive approach, adequate end-plate coverage was obtained with slight root traction and minimal facet joint resection, due to the small size of the single modules. A large footprint reduces the possibility of implant subsidence and migration even when used as a stand-alone implant without posterior stabilization.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577v

A022: Minimally Invasive Transforaminal Lumbar Interbody Fusion and Instrumentation (MIS-TLIF) for the Treatment of Lumbar Isthmic Spondylol Isthesis: Minimum 2-Years Follow-up with Clinical and Radiological Outcomes

Abstract

Introduction:

To explore the clinical and radiological outcomes of MIS-TLIF in the treatment of lumbar isthmic spondylolisthesis.

Material and Methods:

32 patients with lumbar isthmic spondylolisthesis underwent MIS-TLIF by the same surgeon in single institution. There were 14 males and 18 females with an average age of 47.5 years old. 21 cases were rated as degree I, 11 as degree II. The surgery, including bilateral decompression, discectomy for neurological relief, interbody fusion, cage insertion and fixation with pedicle screw, was conducted through a small paraspinal incision and assisted with the Quadrant system. VAS and ODI were adopted to evaluate the clinical manifestation pre- and postoperative. The pre- and postoperative spinopelvic parameters including PI sacral slope, PT, LL, and sagittal vertical axis from C7 plumb line were evaluated.

Results:

The average follow-up period was 29.6 (24-72) months. The scores of VAS and ODI after sugery and at the final follow-up were lower than those bofere sugeryc (P < .05). The height of intervertebral space after surgery and at the final follow-upincreased significantly compared with that before surgery (P < .05). All operated vertebral segments achieved solid bony fusion at the follow-up of 6.5 months postoperatively. The slip degree, slip angle, and HOD improved significantly. Pelvic parameters and sagittal balance improved subsequently. SS was increased by 4.5 degrees, and PT was decreased by 4.5 degrees. LL was increased by 5.0 degrees and sagittal balance was displaced 5.4 mm backward.

Conclusion:

MIS-TLIF may be an easy and safe way in the treatment of lumbar isthmic spondylolisthesis. With local deformity corrected after surgery, all spinopelvic parameters changed subsequently.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577w

A023: Pure Lateral and Oblique Lateral Inter-body Fusion for Treatment of Lumbar Degenerative Disk Disease: Comparison of Two Different Techniques

Abstract

Introduction:

Inter-body fusion techniques for degenerative disk disease (DDD) are still a controversial indication in the current literature. Although good clinical results have been reported in several randomized clinical trials for a variety of fusion procedures, the lack of clear indications in the treatment of lumbar DDD and the opportunity to fuse may be partially attributed to the invasiveness of open surgical approaches, which often seem to be overly aggressive procedures for a disease that has been shown to benefit even from conservative treatment. Nevertheless, the emerging diffusion of minimally invasive spine techniques, such as LIF or OLIF, is progressively changing the indication for treating patients with lumbar DDD because they can achieve mono- or plurisegmental interbody fusion, allowing much faster recovery with a very low rate of complications.

Materials and Methods:

Between January 2010 and September 2015, at our institution, 45 patients (67 levels) underwent lumbar interbody fusion for pure lumbar DDD above the level of L5–S1 through both pure lateral trans-psoas approach (LIF) (n = 31) or oblique lateral retroperitoneal approach (OLIF) (n = 14). Preoperative radiological evaluation included lumbar MRI, CT scan, and dynamic X-rays. Inclusion criteria were chronic axial low back pain exacerbated by prolonged standing and trunk mobility and previous conservative treatment for a period of at least 6 months failed. Patients with radiologically demonstrated frank segmental instability and/or frank radicular conflict and/or those with lumbar stenosis due to spondilosis, were excluded from the study. Only patients with at least 6 months of follow-up were included in the analysis. Clinico-neurological evaluations with VAS, ODI, and SF-36 tests were routinely performed before the intervention and repeated at follow-up to evaluate the clinical course and quality of life. Statistical analyses were performed using SPSS version 15 software (Chicago, IL, USA). P < .01 was considered significant.

Results:

The total levels treated are 67: L2-L3 in 7 cases (10.4%, 6 in the LIF group and 1 in the OLIF), L3–L4 in 31 cases (46.3%, 28 LIF and 3 OLIF), L4–L5 in 21 cases (31.3%, 15 LIF and 6 OLIF) finally L5-S1 in 8 cases (12.0%, all in the OLIF group). Only two intraoperative complications happened without further events: one patient of the OLIF group presented the rupture of the left common iliac vein due to the blades of surgical retractor, and one patient of the LIF group presented a peritoneal laceration; both the complications were successfully treated. In the post-operative period, 21 patients (46.6%, 19 in the LIF group and 1 in the OLIF group) presented motor deficit (3/5 motor) in the ankle flexion associated to a dysesthesia at the territory of L3 and L4. These symptoms had a progressive resolution within 4 to 6 weeks. 5 patients of the LIF group presented a psoas hematomas, which needed 4 days of bedrest. Two patients of the LIF group presented an L4 palsy with a partial resolution in 1 year. In the OLIF group, 7 patients of the oLIF group presented a fluid retroperitoneal collection which did not require ani treatment in any case and one patient presented persistent pain at the surgical side. Regarding the clinical evaluation with the VAS scale, ODI and SF-36 all the patients presented good results at the final follow-up. In the VAS scale appear a difference of 1.27 points between the LIF and the OLIF group in the post-operative period. Similar results are presents in the ODI where the mean difference result of 7.3%, and in the SF-36 tests where regarding the physical scale the difference results of 6.22 points and in the mental scale the difference of 1.55 points in favor of LIF group.

Conclusions:

LIF and OLIF represent mini-invasive procedures for treatment of lumbar DDD. Although generally considered more complex compared to traditional posterior procedures, they are safe and effective, allowing the resolution of disk pain with short hospitalization and fast daily activity recovery. The selection of patients and a good preoperative planning, seem to be detrimental factors to obtain good clinical results.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577x

A024: The Benefits of Minimally Invasive Posterior Lumbar Interbody Fusion in Degenerative Lumbar Spondylolisthesis

Abstract

Introduction:

The use of minimally invasive surgical (MIS) procedures for the treatment of degenerative lumbar spondylolisthesis is increasing although the outcomes of standard open posterior lumbar fusion surgery remain efficient. The question remains what exactly are the benefits of MIS procedures. The aim of the study was to determine the difference between minimally invasive TLIF (MI-TLIF) results and open TLIF procedures regarding the clinical outcomes, perioperative parameters, fusion rate and adverse events.

Materials and Methods:

In the study, 30 patients with the painful, lumbar degenerative spondylolisthesis (Grade I) not responding to conservative treatment were treated with the open TLIF procedure and 30 patients with minimally invasive TLIF procedure. Clinical outcomes were assessed before, 6 months, one year and two years after the procedure using the Oswestry Disability Index (ODI) and Visual analogue score (VAS) for back and leg pain, with 15% improvement in ODI and 20% in VAS defined as a clinically significant. The perioperative parameters including blood loss, operative times, exposure to fluoroscopy and length of hospital stay were evaluated. The CT scans of the patients were taken accordingly in order to determine the fusion rate.

Results:

There was a significant improvement for back and leg pain according to ODI and VAS score in both groups with no statistically important difference between the two groups. There was less blood loss and faster recovery time in the MI-TLIF group but higher fluoroscopic exposure and slightly higher length of the surgeries. The fusion rate was the same in the open and MI-TLIF group.

Conclusions:

Both procedures resulted in significant pain reduction and good functional outcome for the patients with better results in the MI-TLIF group regarding the hospital stay and blood loss. According to our results and according to the literature reviews there is still not enough evidence to state that one procedure is superior to other. In time, the MIS procedure might slowly replace the open technique.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577y

Adult Deformity 1
A025: External Validation of MiSLAT Algorithm and Role of XLIF in Management of Adult Degenerative Deformity of Spine

Abstract

Introduction:

Surgical goals in adult degenerative scoliosis patients are to reduce pain, correct and prevent further deterioration of deformity, restore coronal and sagittal plane balance. Open long segment reconstructions are associated with high complication rates. In view to reduce surgical morbidity, minimally invasive surgeries have been recommended. However, not all adult spinal deformities can be treated with minimally invasive techniques. Several classifications and treatment levels have been recommended. One such algorithm is MiSLAT treatment level. Aim of our study was to assess the external validity of MiSLAT algorithm and to assess the role of XLIF in management of adult degenerative deformity of spine.

Material and Methods:

This was a prospective interventional case series from of patients with symptomatic adjacent segment disease, localised and generalised degenerative deformity of spine who underwent XLIF procedure. MiSLAT algorithm was used to decide treatment level for patients. Pre and post-operative patient reported outcome measures like ODI, VAS score, EQ VAS, EQ-5D index were recorded. Radiological parameters like Cobb angle, lumbar lordosis, pelvic tilt, sacral slope and pelvic incidence were analysed pre and post operatively. Complications rate was reviewed.

Results:

41 patients had XLIF from May 2012 to January 2016. There were 17 males and 24 females. Mean age at surgery was 61.8 years (range 50 – 94) with a mean follow up of 20.46 months (range 7 – 51). Twelve patients were operated for adjacent segment disease, 13 for localised deformity and remaining 16 for generalised deformity. Among 13 localised deformities, there were 3, 9 and 1 patients with MisLAT type II, III and IV classification respectively. Sixteen of generalised deformity group included 10, 1, 5 patients with MisLAT type IV, V and VI respectively. There was statistical significant difference between pre and post-operative ODI, VAS score, EQ VAS, EQ-5D index. Mean pre and post-operative scoliosis and lumbar lordosis in localised deformity was 11, 23.6 degrees and zero, 28.6 degrees respectively. In generalised deformity group, pre and post-operative scoliosis, lumbar lordosis and pelvic tilt were 27, 14.7, 37 degrees and 12, 34, 16.3 degrees respectively. There were 11 complications (26.8%), including two femoral nerve palsies and one death from pulmonary embolism. The reoperation rate was 4.8% (2 patients) for non-union.

Conclusions:

XLIF can be used as surgical tool in MiSLAT types II, III and IV deformities, whereas for MiSLAT types V and VI, XLIF can be used in conjunction with open techniques to correct deformity. MiSLAT algorithm can be used safely to guide management plan in adult degenerative deformity of spine. In addition, XLIF has lower complication rates compared to other open surgeries mentioned in literature to date.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577z

A026: Do Different Types of UIV Instrument Impact Acute Proximal Junctional Failure (Acute PJF) following Adult Spinal Deformity Surgery? PS vs. Hook

Abstract

Introduction:

Some studies have indicated PS fixation at UIV is thought to be a possible risk factor of PJF. The purpose of this study was to retrospectively compare the incidence of acute PJF between transverse hook fixation at UIV and PS following ASD surgery.

Methods:

Forty-seven ASD patients who underwent corrective surgery by a single surgeon were retrospectively reviewed with a minimum 1-year follow-up. The mean age was 67.6 years old (42-83) and the follow-up period was 36.9 months (12-95). T9 as UIV was selected in 17 patients and T10 in 30 patients. Transverse hook was used in 26 patients, and PS was used in 21 patients. Radiographic parameters including SVA, PI-LL, PT, and proximal junctional angle (PJA) were measured before surgery (PreO) and latest follow-up period (PO). Fracture risk was also evaluated using FRAX (WHO Fracture Risk Assessment Tool) before surgery. Acute PJF was defined as UIV and UIV+1 fracture, implant failure or PJK > 15° within the first six months. We compared the several data between the hook group and the PS group with statistical software.

Results:

The hook group had an acute PJF rate of 19.2% compared to 28.5% in the PS group (P = .20). The mechanisms of acute PJF are as follows; there were 4 patients with UIV fracture and 1 patient with implant failures in the hook group, and there were 6patients with UIV fracture in the PS group. Radiographic parameters in the hook group (PreO/PO) were following; SVA; 119.1/39.1 mm, PI-LL; 46.4/4.6°, and PT;35.8/21.9°. Those in the PS group were as follows; SVA; 92.3/37.3 mm, PI-LL; 37.6/4.5°, and PT;31.9/21.8°. FRAX were 13.7% in the hook group and 13.4% in the PS group. There were no differences in baseline data between the two groups. However, the changes of PJA in the PS group were significantly higher than those in the hook group (7.4/2.9°; P = .05). To analyze the PJA data in the patients with Acute PJF, the changes of PJA were significantly higher in the PS group than those in the hook group (17.0/6.3°; P = .04).

Conclusion:

Our study doesn’t show that transverse hook as UIV instrument can prevent acute PJF. However, using hook at UIV can prevent the vertebral collapse if UIV fracture occurs. The increased risk of collapse of UIV fracture in the PS group in this study may due to higher mechanical load to UIV using PS. Further biomechanical study should be necessary to clarify our results.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577aa

A027: Towards Global Standardisation of Measuring Outcomes in Adult Spinal Deformity Surgery

Abstract

Introduction:

Adult Spinal Deformity (ASD) causes severe functional disability, reducing the overall quality of life. In view of the growing ASD population, routine monitoring of outcomes covering the overall quality of life, functioning, and disability from a patient’s perspective, will play an important role in future reimbursement and healthcare systems.1,2 In this era of value based care, healthcare providers are putting more emphasis into assessing the value (health gain per unit cost) of treatment provided. In particular for ASD surgery, where a tremendous treatment variability exists, outcome monitoring by means of outcome registries would be of value. However, outcome registries are most valuable if they are comparable between countries and include outcomes that are relevant to the patient population of interest.3 Standardising patient-reported outcomes (PROs) is a key first step; however, this can only achieve its maximum benefit when the measures used are uniform, valid, reliable and risk-adjusted. Therefore, the aim of this study is to highlight the current strengths, weaknesses and gaps in PROs used for assessment of ASD, to provide recommendations for future improvements, and to serve as a foundation for the process of seeking global consensus on standardising outcomes measures in future clinical trials and spine registries worldwide.

Material and Methods:

This study ultimately consists of three phases: 1) a systematic review of patient-reported outcome used to evaluate outcomes after ASD surgery. We used the domains of the WHO International Classification of Disability, Functioning and Health (ICF) as a framework. 2) a modified five-round Delphi study among international experts starting April 2017, and 3) validation with patient focus groups.

Results:

Phase 1. The systematic review identified 144 papers that met inclusion criteria, and nine frequently used PROs were identified, such as the ODI, SRS-22 and VAS. These measured 29 potential ICF outcome domains, which could be grouped into 3 of the 4 main ICF chapters: body function (n = 7), activity and participation (n = 19), and environmental factors (n = 3). The three most frequently measured outcome domains are: ‘sensation of pain’, ‘recreation and leisure’, and ‘walking’.

Conclusion:

Outcome domains related to ‘mobility’ and ‘pain’ are represented well by PROs used in the current literature. Outcomes related to ‘neurological function’ and ‘pulmonary function’, both significantly affected by ASD surgery, are currently not reported.4,5 These findings indicate that currently used PROs may be inadequate to measure all relevant outcomes in ASD patients. In order to achieve a standardised approach and improvement of individual patient evaluation, consensus on a core set of outcome domains for ASD is urgently needed. In phase 2, using a modified Delphi method, the results of this preparatory study will provide the foundation for the development of a global set of core domains, measurement instruments (patient-reported and clinician-based) and contributing factors to these outcomes. The development of this core outcome set will facilitate comparisons across studies, registries, and nations in order to improve the quality of daily clinical practice in this increasing group of patients, with an increasing burden on society.

References

1. Porter, M. What is Value in Health Care? N. Engl. J. Med. 2477–2481 (2010). doi:10.1056/NEJMp1415160

2. Harwood, J. L., Butler, C. A. & Page, A. E. Patient-Centered Care and Population Health: Establishing Their Role in the Orthopaedic Practice. J. Bone Joint Surg. Am. 98, e40 (2016).

3. Porter, M. E., Larsson, S. & Lee, T. H. Standardizing Patient Outcomes Measurement. N. Engl. J. Med. 374, 504–506 (2016).

4. Lenke, L. G. et al. Neurologic Outcomes of Complex Adult Spinal Deformity Surgery: Results of the Prospective, Multicenter Scoli-RISK-1 Study. Spine (Phila. Pa. 1976). 41, 204–12 (2016).

5. Lehman, R. A., Kang, D. G., Lenke, L. G., Stallbaumer, J. J. & Sides, B. A. Pulmonary Function Following Adult Spinal Deformity Surgery: Minimum Two-Year Follow-up. J. Bone Jt. Surg. 97, 32–39 (2015).

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577ab

A028: Outcomes in Primary Adult Deformity Surgery: What Happens to Patients Who Are Lost to Follow-up?

Abstract

Introduction:

Loss to follow up is highly prevalent after orthopedic surgery. Measuring clinical outcomes after surgery is important to guide an evidence-based approach to care. Loss to follow-up in randomized control trials or clinical registries may present a bias to assessing the efficacy of treatments and reduce the statistical power of study results. Current literature fails to demonstrate the effect of loss to follow up in clinical outcomes studies for ASD. The purpose of this paper is to report the reasons that patients lost to follow-up did not follow-up and the outcomes of care in these patients.

Material and Methods:

A survey was administered remotely to study a consecutive series of patients who were lost to follow up at greater than one year after being treated with primary multilevel spinal fusion with pelvic fixation for ASD. Patients were excluded if they declined participation or were deceased. Demographic, surgical, and health related quality of life data were collected directly from administrative and medical ontologies. All records were chart reviewed and source verified for accuracy. Four patients were excluded from the study as they were deceased and three patients declined participation in the phone survey.

Results:

The cohort included 38 patients who were not seen in clinic at one year or greater from their index surgery and 45 patients who followed-up routinely. There was no significant difference in patient reported outcomes between those who followed up and those who were lost to follow up (P = .97). The average improvement in EQ-5D utility score for those lost to follow up was 0.15 while those who followed-up regularly experienced a mean change of 0.17. Mean length of follow up for all patients was 911 days. Patients lost to follow up had significantly lower revision surgery rates than those who followed up (P = .03). All elective revision surgeries on patients lost to follow up were performed by the same surgeon within one year of their index operation. One emergency revision surgery was performed at an outside hospital after a patient was admitted directly from their local ED. ASA scores were significantly higher in patients who were lost to follow up (P = .01). BMI was also a significant predictor of loss to follow up (P = .05). Reasons for not following up in clinic included: I was not offered an appointment (n = 8), I feel good (n = 7), I stay in touch remotely (n = 7), I live too far away (n = 7), I plan to come in soon (n = 6), I was disappointed with my results (n = 5), my surgeon left the institution (n = 4), I see a doctor at home (n = 3), and I didn’t want to find out I need another surgery (n = 1).

Conclusion:

There are many barriers to follow up from both a patient and a provider’s point of view. Patients who are lost to follow up at greater than one year have similar outcomes as those who follow up in clinic at routine intervals. Advances in telehealth should be directed towards facilitating patient monitoring and the collection of patient reported outcomes after surgery.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577ac

A029: Complication Rate in Adult Deformity Surgical Treatment: Safety of the Posterior Osteotomies

Abstract

Introduction:

The treatment of adult scoliosis is a continuous challenge even for expert spinal surgeons especially in patients over 50 years old. In some adult patients who present with severe, rigid curves, the use of vertebral osteotomies may be necessary to achieve adequate correction of the deformity. Several general and neurologic complications have been reported, in particular associated with PSO. The aim of this study was to report and analyse the perioperative complications and radiographical results in elderly patients undergoing vertebral osteotomies for spinal deformity correction.

Materials and Methods:

Our population was composed of 72 consecutive cases of kyphoscoliosis with different sagittal imbalance situations. All patients were classified according to Berjano-Lamartina classification; they were divided into two groups according to the corrective osteotomies they underwent: we only practiced SPO and/or PO in patients that composed group A; we practiced also PSO in patients that composed group B. We retrospectively reported and analysed the perioperative complications. An independent observer collected for each patient on X-rays the following data: Cobb angle, pelvic incidence (PI), pelvic tilt (PT), sacral slope (SS), lumbar lordosis (LL), thoracic kyphosis (TK), C7 plumb line (C7PL). The average follow-up was 30 months.

Results:

The mean age of our study group was 60.7 ± 10.2 years and the median age of 62 years (range: 42 – 82 years old). We had 50 cases of degenerative (spinal) segment diseases (DSD) Type III, 13 cases of Type IVa DSD and 9 cases of Type IVb DSD. Our overall complication rate was 22.2% (16/72 patients). Patients we treated with SPO and/or PO had a complication rate of 16.9% (10/59 patients) wile patients we treated also with PSO had a complication rate of 46.2% (6/13 patients). The mean Cobb primary curve angle of the cohort was 41.75° ± 18.06, residual scoliosis after surgery was 15.41° ± 10.7; the difference between the pre-operative and post-operative Cobb angles was statistically significant (P < .001). We found a pre-operative C7PL average value of 4.49 cm (±4.82), while the post-operative one was 2.08 cm (±3.44), with statistically significant difference.

Discussion:

The surgical treatment of adult deformities is a challenge also because of the high incidence rate of general and mechanical complications reported in the literature. The posterior surgery necessitates a major multilevel arthrodesis procedure be performed also by using different osteotomies techniques. Previous studies have shown increased complication rates with fusion procedures in elderly patients and our experience support this evidence. Our clinical and radiographic study demonstrates an high incidence of intraoperative complications rate in elderly patients underwent a PSO.

Conclusions:

PSO is a very useful technique to treat rigid high-grade spinal deformity of the adult but patients who undergo a PSO are at high risk of complications. Our experience demonstrates that patients over 60 with degenerative spinal deformity and sagittal imbalance candidate to a pedicular subtraction osteotomy have 46% of complications rate. PSO is a demanding technique to be considered in very selected and motivated patients who must be carefully informed about the risks of the procedure.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577ad

A030: Adult Spinal Deformity over 70 Years of Age: A Two-Years Follow-up Study

Abstract

Introduction:

Decision making in adult spinal deformity (ASD) is one of the most difficult issue in estimating the effects of complications on the outcomes of treatment, especially for surgery in elderly population. The aim of this study was to analyze the decisive factors leading to the specific treatment modalities (i.e., operative vs. non-operative) by comparing the baseline characteristics of operative vs. non-operative patients with ASD over 70 years of age. Moreover, to evaluate the safety and efficacy of surgery; and to compare operative and non-operative management of patients with ASD over 70 years of age even with the setting of complications with a follow-up period of 2 years.

Materials and Methods:

A retrospective review of collected data from a multicenter database on ASD was performed. Patients over 70 years of age with spinal deformities who were scheduled to undergo surgical treatment and who were treated and/or followed without surgical intervention, participated in this study. Demographic, clinical, surgical, radiological features and HRQOL (SF-36 MCS, SF36-PCS, SRS-22 and ODI) parameters of such group of patients were evaluated pre and post-treatment. Peri/postoperative complications, classified as major (life threatening or requiring additional surgery) and minor were also investigated for their effects on HRQOL parameters at 2 years follow-up.

Results:

The database had 181 patients (F: 151, M: 30) entry for both operative (n = 85) and non-operative (n = 96) group over 70 years of age with ASD. Of these, 90 of them (F: 71, M: 29; operative: 61, non-operative: 29) had 2-years follow-up. The comparison between operative and non-operative group for demographic, clinical, radiological and HRQOL parameters at baseline showed statistical significance for all the HRQOL parameters, some of the radiological features including; major coronal Cobb angle, proximal thoracic, main thoracic, thoracolumbar and lumbosacral curves; and SRS-Schwab Curve type (P < .05). The calculated optimal cut-off values to diverge operative and non-operative groups for COMI, ODI, SF-36 PCS and SRS-22 were 5.7, 37.0, 37.5 and 3.2, respectively (P < .05). All operative patients (n = 61; F: 46, M: 15) were treated with posterior surgery. A total of 39 osteotomies and 24 interbody fusions were performed. Overall, 135 complications (71 major, 64 minor) and 1 death were observed. The reoperation rate was calculated as 62.3% at the end of 2 years. For all HRQOL parameters except SF-36 MCS, surgically treated patients significantly improved by means of HRQOL parameters two years after the surgery even with the setting of complications (P < .05).

Conclusion:

This study has demonstrated that surgery provides significant improvements in pain, disability and body perception in patients with ASD over 70 years of age with a follow-up of 2 years, even with the setting of complications.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577ae

Navigation
A031: Comparison Peri-operative Factors during Minimally Invasive Pre-psoas Lateral Interbody Fusion of the Lumbar Spine using Either Navigation or Conventional Fluoroscopy

Abstract

Introduction:

The OLIF has widely been applied in the treatment of degenerative diseases of the lumbar spine. In this operation, fluoroscopic guidance is most often used; however, navigation has been shown to improve the accuracy of implant placement and reduce radiation exposure. The aim of this study is to compare intraoperative conditions and clinical results of patients undergoing pre-psoas oblique lateral interbody fusion (OLIF) using navigation or conventional fluoroscopy (C-ARM) techniques.

Material and Methods:

Patients underwent the OLIF procedure at two tertiary care medical centers, and records were reviewed. Forty two patients were identified; 22 patients underwent the OLIF with navigation, and 20 underwent the procedure with fluoroscopy. Operating time, estimated blood loss, length of hospitalization, surgery-related complications, total radiation exposure and total radiation time were recorded and compared between the 2 groups. Clinical outcomes according to the Smiley-Webster Scale were evaluated. Patients were followed up with a range of 6 to 24 months.

Results:

There were no significant differences between groups with respect to mean age, gender, weight, primary diagnosis and surgical procedures. The navigation group had zero radiation exposure to the surgeon and radiation time compared to the C-ARM group, with total radiation exposure of 44.59 ± 26.65 mGy and radiation time of 88.30 ± 58.28 seconds (P < .05). For the radiation exposure to the patient, it was significantly lower in the O-ARM group (9.38 mGy) compared to the C-ARM group (44.59 ± 26.65 mGy). Operating room time was slightly longer in the navigation group (2.49 ± 1.35 h) compared to the C-ARM group (2.30 ± 1.17 h) (P > .05), although not statistically significant. No differences were found in estimated blood loss, length of hospitalization, surgery-related complications and outcome scores with an average of 8 month follow up.

Conclusion:

Compared with C-ARM techniques, using navigation can eliminate radiation exposure to surgeon and decrease radiation exposure to the patient, and it had no significant effect on operating time, estimated blood loss, length of hospitalization, or peri-operative complications in the patients with OLIF procedure. This study shows that navigation is a safe alternative to fluoroscopy during the OLIF procedure in the treatment of degenerative lumbar conditions.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577af

A032: Cervical Pedicle Screw Instrumentation: Analysis of Placement Accuracy with O-Arm Based Navigation

Abstract

Introduction:

Despite superior biomechanical properties, the use of pedicle screws in cervical spine remains limited due to technical difficulties and high complication rates. The purpose of this study is to evaluate the usefulness and limitations of navigation technologies incorporating intra-operative 3D-imaging with O-arms in accurate placement of cervical pedicle screws.

Material and Methods:

A total of 38 patients who underwent cervical pedicle screw instrumentation by single surgeon were included in the study. All the pedicle screws were placed using the same 3D-Navigation system. Intra-operative 3D-images were obtained before and after placement of screws and results were evaluated.

Results:

The study included analysis of 202 cervical pedicle screws inserted in 38 patients. The indications for surgery included trauma, degenerative spine disease, tumor and infection. Out of the 202 screws, 170 (84.16%) were inserted at the level of C3-C6 vertebrae, followed by 20 (9.9%) and 12 (5.94%) screws at C2 and C7 vertebrae, respectively. After analsysis of screw placement as per Gertzbein Classification, the overall breach rate was found to be 8.4% (17 screws) with 58.82% grade I, 41.18% grade II and nil grade III screw breaches. All the breaches were lateral with highest breach rate at C5 (12.5%) followed by C6 (11.9%) vertebral level. Despite breaches, there were no neurovascular complications due to placement of any of the pedicle screw.

Conclusion:

The use of intra-operative 3D scans for navigation can make cervical pedicle screw placement more accurate. Better accuracy and intra-operative control can increase surgeon’s confidence in using cervical pedicle instrumentation on more regular basis.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577ag

A033: Computer Assisted Robotic Surgery in the Octogenarians: A Case Controlled Study

Abstract

Introduction:

The proportion of population over the age of 80 is growing undergoing spinal surgery is growing. The use of computer assisted surgery in these patients is challenging due to poor bone quality and at times complex anatomy. We here present a consecutive series of octogenarian patients who underwent robot guided spine surgery robotic (planning of entry point and trajectories, drilling and cannulation of the pedicles).

Methods:

Prospective data in a spine referral center for robot guided spine surgery was retrospectively analyzed. All patients who were 80 years old or older at the time of surgery were identified. These patients were matched to 120 patients under the age of 80 (a 3:1 ratio). Patients’ age, sex and indication for surgery were documented. Procedure time, accuracy, fluoroscopy usage time, and any instrumentation related complication were documented.

Results:

Between 2007 and 2013, 192 trajectories were executed in the octogenarian patients and 568 levels in the younger patients. The average age was 83.9 years vs 61.2 (P < .05), 12 patients were males in the octogenarian vs 50 in the younger patients. The highest instrumented in both groups vertebra was T5 and the lowest was S1. MIS was performed in 25 octogenarian patients and 73 younger patients. Average robotic usage time was 6 min and 40 seconds compared to 5 min and 5 seconds in patients under the age of 80 (P < .05); Total fluoroscopy exposure time per screw was 16.3 seconds in the octogenarian’s vs 9.3 seconds in the younger patients (P < .05). 182 (94.5%) executed trajectories were accurate vs 545 (95.9%) accuracy in patients under the age of 80 (NS). No intraoperative complications related to robot usage occurred.

Discussion:

Spine surgery in the octogenarians is challenging. The combination of osteoporotic bone and multiple spine pathologies in robot guided procedures results in longer procedures and in higher fluoroscopy usage compared to younger patients. However, procedure accuracy and safety is identical to younger patients, allowing optimal instrumentation in these frail patients.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577ah

A034: Surgical Outcomes of Robotic-Guidance vs. Freehand Instrumentation: A Retrospective Review of 705 Adult Degenerative Spine Patients Operated in Minimally Invasive (MIS) and Open Approaches

Abstract

Introduction:

Minimally invasive spinal fusion surgeries (MIS) are becoming more common as hardware and computer guidance systems evolve. Yet MIS is still the exception rather than the norm with several barriers to adoption that focus on the learning curve, increased radiation exposure and contested clinical value to the patient. In recent years, robotic-guidance has become available for spinal surgeries, aiding surgeons in shortening the learning curve of MIS techniques and reducing the intraoperative exposure to harmful radiation. However, few data were presented on its impact on clinical outcomes, especially in the hands of experienced MIS surgeons.

Materials and Methods:

Data were collected retrospectively from 4 surgeons for patients operated with robotic-guidance in a MIS approach (RGM), and compared with patients operated with fluoroscopic-guidance MIS (FGM) or open (FGO) approaches. All cases were instrumented fusions using either a minimally invasive technique with pedicle screws inserted in a percutaneous para-median approach, or a classic open approach through a median dissection. Logistic regression analysis was used to assess the odds ratio of complications and surgical revisions.

Results:

Altogether, data from 705 patients were collected, 403 RGM patients, 224 FGM and 78 FGO. There were no significant differences in age, sex or BMI between arms or surgeons, except for 1 of the 4 groups in RGM that was significantly older by about 6 years. The complication rates were 4.0%, 5.4% and 12.8% for RGM, FGM and FGO respectively. The revision rate for RGM was 3.8% while for both FGO and FGM it was 7.7%. A logistic regression was performed and demonstrated that the odds ratio for surgical complications were 3.0 for FGM (P = .014, 95% confidence interval (CI95) = 1.2-7.1) and 3.1 for FGO (P = .009, CI95 = 1.3-7.3). The odds ratio for surgical revisions was 3.8 for FGM (P = .006, CI95 = 1.5-10.0), and 1.9 for FGO but it was not statistically significant (small sample size). Surgeon, age, gender, BMI, or length of surgery, were non-significant parameters in the regression model.

Conclusions:

This retrospective analysis demonstrates that use of robotic guidance MIS can significantly reduce surgical complications and revision surgeries when compared to fluoro-guided MIS in the hands of experienced MIS surgeons.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577ai

A035: Spinal Intra-operative Three-Dimensional Navigation: Correlation between Clinical and Absolute Engineering Accuracy

Abstract

Introduction:

Spinal intra-operative computer-assisted navigation (CAN) may guide pedicle screw placement. CAN techniques are reported to reduce pedicle screw breach rates across all spinal levels. However, definitions of screw breach vary widely across studies, if reported at all. The absolute quantitative error of spinal navigation systems is theoretically a more precise and generalizable metric of navigation accuracy. It has also been computed variably, and reported in fewer than a quarter of clinical studies of CAN-guided pedicle screw accuracy. The aim of this study was to characterize the correlation between clinical pedicle screw accuracy, based on post-operative imaging, and absolute quantitative navigation accuracy.

Material and Methods:

We reviewed a prospectively-collected series of 209 pedicle screws placed with CAN guidance, in 30 patients undergoing first-time posterior cervical/thoracic/lumbar/sacral instrumented fusion ± decompression. Each screw was graded clinically by multiple independent raters using the Heary and 2 mm classifications. Clinical grades were dichotomized per convention. The absolute accuracy of each screw was quantified by the translational and angular error in each of the axial and sagittal planes.

Results:

Acceptable screw accuracy was achieved for significantly fewer screws based on 2 mm grade vs. Heary grade (92.6% vs. 95.1%, P = .036), particularly in the lumbar spine. Inter-rater agreement was good for the Heary classification and moderate for the 2 mm grade, significantly greater among radiologists than surgeon raters. Mean absolute translational/angular accuracies were 1.75mm/3.13° and 1.20mm/3.64° in the axial and sagittal planes, respectively. There was no correlation between clinical and absolute navigation accuracy.

Conclusion:

Radiographic classifications of pedicle screw accuracy vary in sensitivity across spinal levels, as well as in inter-rater reliability. Correlation between clinical screw grade and absolute navigation accuracy is poor, as surgeons appear to compensate for navigation registration error. Future studies of navigation accuracy should report absolute translational and angular errors. Clinical screw grades based on post-operative imaging may be more reliable if performed in multiple by radiologist raters.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577aj

A036: Intraoperative Computed Tomography versus iso-C 3D C-Arm for Navigated Spinal Instrumentation

Abstract

Introduction:

Recent meta-analysis have evidenced the superior accuracy of navigated spinal instrumentation compared to non-navigated techniques. However, the benefit of intraoperative computed tomography (iCT) compared to intraoperative iso-C 3D C-arm (3D C-arm)-based navigation remains unclear. The aim of the present study was to report our experience and accuracy of navigated pedicle screw insertion with intraoperative CT or 3D C-arm-based spinal imaging in 254 consecutive patients.

Materials and Methods:

After exposure and attachment of the navigation tracking device, a first iCT or 3D C-arm scan was performed with automatic patient/image co-registration and navigated screw insertion. Screw positioning was then intraoperatively assessed by a second iCT or 3D C-arm scan, based upon which the intraoperative accuracy was determined. In cases that required intraoperative screw revision, navigated repositioning was performed based on the second iCT or 3D C-arm scan. Thereafter, a third iCT or 3D C-arm scan was performed to confirm repositioning. In cases with 3D C-arm navigation, a postoperative CT scan was routinely performed, based upon which the final accuracy was determined compared to the final iCT scan. The general intraoperative screw placement assessability through iCT or 3D C-arm and the intraoperative and final accuracies were retrospectively reviewed and analyzed by an independent observer.

Results:

Between 2013 and 2016, an implantation of 1359 pedicle screws was performed in 254 patients with either iCT (1063 screws) or 3D C-arm (296 screws) based spinal navigation and automatic patient/image co-registration. The indications for surgery were degenerative disease (155/254; 61%), infectious disease (28/254; 11%), tumors (33/254; 13%) and trauma (38/254; 15%). Direct intraoperative screw assessment with iCT was successfully accomplished for each screw in all patients. In contrast, 19.2% (57/296) of the screws assessed by 3D C-arm imaging were intraoperatively not clearly assessable due to hardware artifacts and limited image quality. Also, 3D C-arm-based spinal navigation yielded lower precision rates compared to navigated instrumentation performed with iCT imaging (intraoperative accuracy: iCT 94.8% vs. 3D C-arm 89.7%, *P < .01; final accuracy: iCT 95.6% vs. 3D C-arm 90.9%, *P < .01). Regarding the immediate intraoperative performance, an analysis of the intraoperative accuracy based on the location of the instrumentation confirmed a significantly higher precision rate of iCT-based screw insertion in the cervical (iCT 98.8% vs. 3D C-arm 84.6%, *P < .0001) and thoracic (iCT 96.4% vs. 3D C-arm 83.3%, *P < .0001) spine, whereas no difference was detected in lumbar-sacral instrumentations (iCT 91.8% vs. 3D C-arm 90.0%; P > .05).

Conclusions:

Both iCT and 3D C-arm-based spinal navigation solutions with automatic patient/image co-registration are able to provide high pedicle screw accuracy rates. However, immediate intraoperative screw placement assessability and screw placement accuracy in the cervical/thoracic spine appear to be limited with intraoperative 3D C-arm imaging alone.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577ak

Lumbar Disc Herniation
A037: Clinical and Radiological Factors Affecting Motor Recovery Following Neurological Deficit in Lumbar Disc Herniation

Abstract

Introduction:

Neurological recovery after surgery is not uniform and varied recovery rates between 61 and 88% have been reported in literature. Existing literature is not clear on the reasons resulting in such discrepancy and possible clinico-radiological factors that affect neurological recovery. The current study is a prospective, large scale case-control study to analyse the role of clinical and radiological parameters in the determining recovery of motor deficit in patients with LDH.

Materials and Methods:

A prospective study was conducted among 556 consecutive microdiscectomy surgeries performed for lumbar disc herniation (L1-2 to L5-S1) during the study period of 15 months.70 consecutive patients who underwent lumbar microdiscectomy for neurological deficit following disc herniation, were followed up for a period of 1 year and assessed for neurological recovery. Presence of motor deficit was considered when clinical examination demonstrated a motor power <3/5 (MRC grading) in any myotomes (L2- S1). Clinical parameters studies included- demographic data, co-morbidities, number of symptomatic episodes, duration of symptoms and neurodeficit, completeness of deficit, presence of bowel and bladder dysfunction and precipitating events. Radiological parameters evaluated included- number and location of herniation level, nature of herniation, presence of migration, bony canal dimension, percentage of canal compromise and dimensions of herniated disc fragment.

Results:

Of these 70 patients with neurodeficit, 5 were lost to follow-up during. 41 out the remaining 65 patients (63%) had completely recovered by 2 months (mean 7.2 weeks). Of the 24 patients (37%) who did not recover in the initial 2 months, 4 (16.7%) patients had a delayed recovery beyond 2 months. Patients with diabetes (p 0.025), longer duration (≥120 days) since initial symptom (p 0.048), greater number (≥2) of previous symptomatic episodes (p 0.006), complete initial deficit (p 0.0001), complete sensory loss (p 0.042), areflexia (p 0.009) and multi-level disc prolapse (p 0.006) showed poorer recovery. The presence of two or more of the risk factors should raise suspicion for poor motor recovery (Sensitivity of 75%, Specificity of 70.7%). Age (p 0.766), sex (0.94), occupation (p 0.75), smoking (p 0.87), onset of symptoms (0.16), precipitating factors (p 0.88), bladder involvement (p 0.265), bilaterality of symptoms (p 0.41), presence or absence of anal reflex (p 0.48), level, type and location of disc herniation, primary canal stenosis (p 0.79) and disc dimension (p 0.96) did not affect the neurological outcome.

Conclusion:

A prospective, consecutive, large series assessing factors contributing to neurological recovery patterns following motor deficit resulting from lumbar disc herniation has not been reported previously. Patients with diabetes, longer duration since initial symptom (≥120 days), greater number of previous symptomatic episodes (≥2), complete initial motor and sensory deficit, areflexia and multi-level disc herniations are predisposed to delayed or poor neurological recovery post-operatively.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577al

A038: Treatment of Pain Due to Nerve Root Compression: Irrational, Ineffective and Inefficient

Abstract

Introduction:

Radicular pain is common (but exactly how common is uncertain) and surgery is known to be effective. However, Surgery is usually preceded by various “conservative” treatments for which there is often unclear rationale and little evidence of efficacy. Hence, the primary objective of this study was to determine the range and frequency of treatments experienced by people eventually having surgery for lumbar and cervical root compression. The secondary objective was to use existing literature to compare the effect size of these treatments on pain compared to that of surgery.

Material and Methods:

Prospectively collected data on consecutive people undergoing surgery by one spinal neurosurgeon for sciatica or brachalgia between January 2007 and July 2015 in a UK teaching and private hospital. People were asked to record their symptom duration, details of previous treatments received, pain severity (Visual Analogue Scale, VAS) and self-reported functional limitations caused by their symptoms.

Results:

Participants preoperative questionnaires were obtained from 93% (n = 1110) of people having surgery for sciatica or brachalgia over nearly 9 years from January 2007 to June 2015. The average age was 58yrs (range 17-94). Half were female (n = 544). The mean duration of symptoms was 35.0 months (sd 70.5; range 0.2-620). 88.7% of people were taking analgesic medication with a mean of 3.3 (sd 2.7) per day; 82% had at least 1 physical therapy; 23.4% had at least 1 injection therapy. Pre and post op VAS pain scores were 7.46 (sd 1.87) v 2.89 (sd 2.72). The improvement in pain was highly significant statistically (t = 36.4; P < .001) and clinically (Cohen’s Effect Size = 2.44).

Conclusion:

People with cervical or lumbar nerve root compression can wait years before receiving surgery that is associated with substantial treatment benefits. During this time, they are in pain, have limited function and receive a range of treatments that are not based on a diagnosis and are predictably ineffective. The literature also shows no convincing evidence to support the non-surgical treatments as effective treatments for cervical and lumbar nerve root compression. Our results indicate that the manifestations of nerve root compression are poorly understood, therefore the threshold for referral and investigation should be lowered, and guidance needs revising.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577am

A039: Clinical and Radiological Factors Associated with Development of Motor Deficit in Lumbar Disc Prolapse: A Prospective Analysis of 70 Consecutive Cases with Neurological Deficit

Abstract

Introduction:

Neurological deficit is a rare, but serious complication following lumbar disc herniation. There are currently very few large scale studies in the literature discussing the correlation of different clinico-radiological factors associated with development of this complication. We aimed to correlate clinical and radiological parameters in the development of motor deficit in patients with lumbar disc herniation in a large scale case-control study.

Materials and Methods:

We conducted a prospective, consecutive analysis, among a total of 556 cases with lumbar disc herniation (L1-2 to L5-S1) treated with microdiscectomy. During the study period of 15 months, 70 consecutive patients who had presented with motor deficit (with or without bladder symptoms) were included under group 1 (cases). The control group (group 2) which included 70 patients without any pre-operative neurological deficit were selected through random allocation Motor deficit was defined as the occurrence of motor power ≤3/5 (MRC grading) in L2, 3, 4, 5, S1 myotomes. Radiological parameters evaluated included- number and location of herniation level, nature of herniation, presence of migration, bony canal dimension, percentage of canal compromise and dimensions of herniated disc fragment. Clinical parameters studied included- demographic data, co-morbidities, symptomatology, number of symptomatic episodes, Oswestry scores, visual analogue scores, occupational profile and precipitating events.

Results:

Patients with diabetes (p 0.004), acute onset of symptoms (p 0.036), L3-4 discs (p 0.001), sequestrated discs (p 0.004), superiorly migrated discs (p 0.012) and central discs (p 0.004), greater antero-posterior disc dimension (p 0.023), primary canal stenosis (p 0.0001); and greater canal compromise (p 0.002) had a significant correlation with the development of neurological deficit. When four of more of these risk factors are present, the chance of occurrence of motor deficit is high (Sensitivity of 74%, Specificity of 77%). Age of patient (p 0.067), sex (p 0.999), previous precipitating events (p 0.379), severity of pain (p 0.605), smoking (p 0.309); and number of herniation levels (p 0.266) did not affect the occurrence of deficit. The patients with associated bladder symptoms were similar to the other subset (without bladder symptoms) with respect to all clinico-radiological parameters. However, the time delay since the occurrence of deficit was significantly shorter in patients with bladder involvement (p 0.001).

Conclusion:

This unique prospective, consecutive analysis of clinic-radiological factors impacting neurodeficit stands out as one of the largest cohort analysis for this complication following lumbar disc herniation. Patients with diabetes, acute presentation of symptoms, central, sequestrated and superiorly migrated discs, high lumbar disc prolapse and greater spinal canal compromise are predisposed to the development of motor deficit.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577an

A040: Management of Symptomatic Lumbar Disk Herniation: An International Perspective

Abstract

Introduction:

Sciatica is a common diagnosis in the general population. Sciatica is most frequently caused by lumbar disk herniation (LDH). Multiple surgical techniques and treatment modalities are available to threat LDH, albeit some with small effect sizes or without compelling evidence. The aim of this survey is to evaluate the current practice patterns and attitudes of surgeons regarding both the surgical and nonsurgical management of LDH worldwide.

Material and Methods:

A survey including questions on the application of physical examination, expectations regarding different surgical and nonsurgical techniques, factors influencing the outcome of surgery and the documentation of PROMs, was distributed among members of AOSpine International and the EANS.

Results:

817 surgeons from 89 countries completed the questionnaire These surgeons perform a total of 62.477 discectomies yearly. Pain medication and steroid injections were expected to be the most effective nonsurgical treatments. The severity of pain and/ or disability and failure of conservative therapy were the most important indications for surgery. A period of 1-2 months of radiculopathy was regarded as a minimum for indicating surgery. Unilateral transflaval discectomy was the procedure of choice among the majority and was expected to be the most effective technique with the lowest complication risk. Almost a third of the surgeons did not register any PROMs.

Conclusion:

Unilateral transflaval discectomy was expected to be the most effective surgical technique. Techniques described as minimally invasive, were expected to give the lowest postoperative low back pain. However, these techniques were also expected to give the highest risk of recurrent disk herniation. Documentation of PROMs in the treatment of LDH is warranted.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577ao

A041: Rare Presentation of Disc Prolapse: Lumber Intradural Disc Herniation

Abstract

Study Design:

Case series.

Objective:

The aim was to look for preoperative clinical and radiological features of intradural disc.

Methods:

We present prospective analysis of 6 cases of intradural disc herniation at L4-L5 level diagnosed on the basis of intraoperative findings with their clinical, intraoperative and retrospective MRI analysis.

Results:

All our cases on preoperative MRI findings were reported as having diffuse annular bulge with large posterocentral extrusion at L4-L5 compressing the nerve roots. Our study comprised of males in age group of 30 to 60 years. 4 out of 6 presented with cauda equina syndrome. In 3 cases, cauda equina was associated with sudden deterioration in the power of lower limb muscle groups. We suspect that intradural herniation of disc was synchronous with cauda equina syndrome in these cases, which was very well documented in one of the cases. On retrospective analysis, MRI findings of mass effect in the form of displacement of the traversing nerve roots due to large central disc with crumble disc sign was suggestive of early evidence of intradural disc herniation. Y sign in ventral dura due to splitting of ventral dura and arachnoid mater by disc material was a good diagnostic sign to suspect intradural extra-arachnoid disc.

Conclusion:

Based on our series and literature review we propose three stages of intradural disc herniation on MRI: Stage 1- Stage of Effacement, Stage 2- Stage of focal discontinuity and Stage 3- Stage of Intradural herniation. We also suggest that sudden deterioration in the power of lower limb muscle groups with cauda equina syndrome in patients having large central disc on MRI especially at L4-5 levels should raise suspicion of intradural herniation of disc.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577ap

A042: Is There a Standard of Magnification in Lumbar Discectomy? A Propensity Scoring Study

Abstract

Introduction:

Numerous methods of magnification are available for spinal surgeons when performing simple discectomy from conventional, loupes and operative microscope. Advantages exist for the use of magnification in clearer operative field and with the operative microscope enhanced illumination of the operative field. There have been reports which have suggested that there is an increase in wound infections with the operative microscope. We ask if there is any evidence to favour magnification compared with conventional methods in the performance of simple discectomy.

Methods:

A retrospective review of a multi-centred internationally kept database was performed (SpineTango). The database was searched for primary discectomies. The results were then stratified into conventional magnification; loupe magnification or operative microscope. These were then compared for the rate of dural lesions during surgery and complications from the surgery.

Results:

We included 6662 operative patients. 1810 were treated by decompression using conventional magnification, 384 by loupe magnification and 4468 by operative microscope. The overall rate of dural lesion was 4.56%. The lowest rates of dural lesions were seen in the conventional group (3.09%) and the highest rate was seen in the Loupes group (8.07%). There was a 1.85 times higher rate of incidental durotomy with the use of surgical loupes. The conventional group had worse outcomes for length of stay, wound infections, surgical time and blood loss.

Conclusion:

Our results fail to show a true standard in the use of magnification for simple discectomy. It would suggest an increase in the use of magnification may reduce blood loos, wound complications and length of stay. The reason for higher dural lesions in the magnification arms may be the use of magnification after a lesion has been created. Further prospective analysis is required to confirm this however.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577aq

Basic Science Growth Factor
A043: Histological Analysis of Bone Regeneration with Different Doses of rhBMP-2 in an Ovine Lumbar Interbody Fusion Model

Abstract

Introduction:

The objective of this study was to investigate the effects of different doses rhBMP-2 on bone healing in an ovine lumbar interbody fusion model.

Materials and Methods:

In this study 22 sheep underwent two level lumbar interbody fusion using a ventrolateral approach with secondary dorsal fixation at L1/2 and L3/4. After randomization in one level a PEEK-cage was implanted filled with one of three doses rhBMP-2 (0,5 mg; 1 mg; 2 mg) delivered on an ACS. The other level received an empty PEEK-cage or ACS filled cage. Animals were sacrificed after 3 and 6 months and decalcified histology was performed. This included histomorphological analysis as well as histomorphometry of the tissues within the cage.

Results:

At 3 months after surgery the groups treated with rhBMP-2 showed higher amounts of bone tissue within the cage. At 6 months the amounts of bone tissue increased in all groups, but were still lower in the groups without growth factor. At 3 months there was only one active osteolysis in the cage/ACS. 7 of 8 segments of the rhBMP-2 groups had a compromised bone structure around the implant. These areas were filled with fibrous tissue and fibrocartilage. This finding was not detected in the groups without rhBMP-2 at 3 months. At 6 months most of the segments with an empty cage or cage/ACS showed a chronic inflammation. Predominant cells were macrophages and giant cells. The groups treated with rhBMP-2 showed only a few mild chronic inflammatory reactions.

Conclusion:

The well-known dose dependent effect of rhBMP-2 on bone healing could also be recognized in our study. Attention has to be payed for the proinflammatory properties of the growth factor. Consistent with other studies we found 2 strong inflammatory reactions, each one in the lowest and highest dose group. Also the potential for causing transient bone resorptions, according to the results of others, was demonstrated. At 3 months 7 of 8 segments treated with rhBMP-2 showed compromised peri-implant bone. Osteoblasts, but not osteoclasts, were seen in the periphery of these areas. It can be concluded that there where bone resorptions which already merged into an increased osteoblastic activity. Usually resorptions occur between 2 and 12 weeks and are followed by a period of increased osteoblastic activity. This finding wasn’t recognized at 6 months anymore. Striking is that at 6 months most of the segments without rhBMP-2 showed a compromised bone structure around the implant with a mild to mainly moderate chronic inflammatory reaction. This cannot be attributed to the growth factor. Also the ACS is degraded at 6 months and is unlikely a possible explanation. Therefore, the cage as a reason must be considered and it has to be questioned whether PEEK is the optimal material for interbody cages.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577ar

A044: A Comparison of the Efficacy of Adipose-Derived vs. Bone Marrow-Derived Stem Cells in Combination with a Clinical-Grade Bone Graft Substitute in a Rat Model of Spinal Fusion

Abstract

Introduction:

Adipose-derived stem cells (ADSCs) have been demonstrated to form vascularized bone in various animal and pre-clinical models. While bone marrow-derived stem cells (BMSCs) have been widely used in spinal fusion studies, adipose offers a number of advantages as an alternative clinical cell source, including a larger available tissue volume, higher stem cell concentration, and reduced donor site morbidity. In this study we compare the efficacy of ADSCs vs. BMSCs in achieving successful spinal fusion when combined with a clinical-grade bone graft substitute in a rat model.

Materials and Methods:

Adipose-derived stem cells (ADSCs) and bone marrow-derived stem cells (BMSCs) were isolated from the inguinal fat pads and long bones, respectively, of female Lewis rats (6-10 wk old) and cultured in vitro until passage 2 (P2) for subsequent transplantation in our spinal fusion model. The frequency of colony forming unit fibroblast (CFU-F) colonies was also assessed in vitro for both ADSCs and BMSCs. Posterolateral spinal fusion surgery at L4-5 was performed on 36 female Lewis rats (6-10 wk old) divided into 3 experimental groups: [1] Vitoss (Stryker) clinical-grade bone graft substitute only (VO) (n = 12); [2] Vitoss + 2.5 x 106 P2 ADSCs /side (n = 12); and [3] Vitoss + 2.5 x 106 P2 BMSCs /side (n = 12). Fusion was assessed at postoperative week 8 via micro-computed tomography (MicroCT) analysis and manual palpation. Manual palpation scoring was conducted by blinded researchers as follows: 0 = non-fused; 1 = some motion across operative joint but not as mobile as adjacent segments; 2 = fused, no motion across the operated joint.

Results:

The average fusion volume in the ADSC group was significantly larger than the BMSC and VO groups (44.3 mm3 vs. 27.6 and 30.0 mm3, respectively, P < .01). The mean manual palpation score was the highest in the ADSC group compared with the BMSC and VO groups (1.5 versus 0.7 versus 0.8 P = .03). As has been found in previous studies, ADSCs exhibited a faster proliferative rate and a higher frequency of CFU-F colonies in vitro than BMSCs.

Conclusions:

When combined with a clinical grade bone graft substitute in a rat model, adipose-derived stem cells yielded increased fusion mass volume and more robust fusion than bone marrow-derived stem cells. Ongoing studies will explore whether this trend holds for freshly isolated and P1 ADSCs as well as in larger animal models.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577as

A045: The Osteogenic Effects of Photo-Immobilization of Bone Morphogenetic Protein-2 using Different Carrier Systems in a Rat Calvarial Defect Model

Abstract

Introduction:

As a preliminary study, we photo-immobilize the BMP2 on the collagen sheet with an UV-light reactive azidophenly-natural polymers (Gelatin, O-carboxymethly chitosan, Low molecular weight chitosan), and determine the optimal density of azidophenyl-natural polymers and UV treatment time. The purpose of this study is to confirm the usefulness of photo reactive Az-gel on collagen sheet for the BMP-2 as a carrier in the rat calvarial defect animal model.

Material and Methods:

Fifty-six male Sprague-Dawley rats, 8 weeks of age, were chosen, randomized into following four groups; Group A as a control group comprising a collagen sheet only cast BMP-2; Group B comprising a collagen sheet with photo-immobilized BMP-2 on azidophenyl-gelatin (Az-Gel); Group C comprising a collagen sheet with photo-immobilized BMP-2 on azidophenyl-O-carboxymethyl chitosan (Az-OCM); and Group D comprising a collagen sheet with photo-immobilized BMP-2 on azidophenyl-low molecular weight chitosan (Az-LMC). The animals were anaesthetized for all surgical interventions, 8-mm defect was made using a trephine burr at animal’s calvaria, and 8-mm collagene sheet, treated according to group) was implanted. Seven animals from each group, a total of 28 animals, were sacrificed at 4 weeks; the remaining 28 animals were sacrificed 8 weeks after implantation. MicroCT analysis and histological assessment involving H&E stain and immunohistochemical stain (RUNX2, osteopontin) were done for qualitative and quantitative evaluation of each group.

Results:

1) MicroCT: At 4 weeks, the bone volume fraction was highest in Group at B but difference between the groups was not significance. However, the bone volume fraction at 8 weeks was highest with significant difference (P = .017). At 4 weeks, the trabecular pattern factor and structure model index, the bone microarchitecture parameter, were lowest at Group B with significant difference (P < .01), indicate that there was more trabecular connectedness in Group B. At 8 weeks, the trabecular number per unit lenght was highest at Group B with significant (P = .01). In the 3-D reconstruction image, the new bone generated in the control group and Group D appeared to be located along the defect rim, and was contradistinctively centrally located bridging the entire major axis of the defect in the Group B and Group C. 2) Histology: The results from the H&E staining, the new bone generation tended to occur at the center of defect, relatively independent site from the host bone in the Group B and Group C. The graft resorption and well maturated trabeculae were observed in all groups. The RUNX2 staining showed a significantly highest positively expressed cellular ratio in Group B at 4 and 8 week (P < .01). The expression intensity of osteopontin was strongest in Group B, followed by Group C, compared with week to moderate in control group and Group D.

Conclusion:

Among the azidophenyl natural polymers, photo-immobilized BMP-2 using Az-Gel on a collagen sheet significantly enhanced new bone formation quantitatively and qualitatively compared with non-photo-immobilized BMP-2 on a collagen sheet. In conclusion, photo-immobilization using Az-Gel on a collagen sheet is a promising technique for the creation of BMP-2 carriers.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577at

A046: A Comparison of Syngeneic Iliac Crest and Femoral Allografts with Iliac Crest Autograft in the Rat Model of Spinal Fusion

Abstract

Introduction:

Autograft iliac crest bone remains the “gold standard” in lumbar spinal fusion procedures, including within animal models. However, inbred rodent strains allow for the use of syngeneic allografts in place of autograft bone. Given that larger volumes of bone are available in the femur and since femoral head allografts have been successfully used in a number of clinical spinal fusion studies, we compared the use of autogenous iliac crest with syngeneic femoral and iliac crest allograft bone in the rat model of lumbar spinal fusion.

Materials and Methods:

Single-level bilateral posterolateral intertransverse process lumbar spinal fusion surgery was performed on 45 female Lewis rats, divided into three experimental groups: [1] iliac crest autograft (n = 15); [2] syngeneic iliac crest allograft (n = 15); and [3] syngeneic femoral allograft bone (n = 15), all consisting of corticocancellous bone. Eight weeks postoperatively, fusion was evaluated via microCT analysis, manual palpation and histology. Bone marrow-derived cells were isolated from the illia and femurs of female Lewis rats, enumerated and cultured in vitro for 10 days in order to determine the frequency of colony unit fibroblast (CFU-F) colonies.

Results:

Pre-implantation femoral syngeneic allografts were the largest at 0.42 ± 0.10 g, followed by iliac crest allografts at 0.35 ± 0.13 g and finally iliac crest autografts at 0.15 ± 0.10 g. However, 8 weeks post-surgery there was no statistically significant difference in fusion mass volume via micoCT analysis. Upon manual palpation, allograft iliac crest bone resulted in the highest fusion rates with 37.5% bilaterally fused, 37.5% unilaterally fused and 25% non-fused, compared to 15% bilaterally fused, 54% unilaterally fused and 31% non-fused in the autograft group and 7%, 40% and 53% in the femoral allograft group. While the total bone marrow-derived cell yield was significantly higher from femurs as opposed to ilia, preliminary limiting dilution CFU-F assays suggest that the frequency of CFU-F colonies is higher in ilia compared to femurs.

Conclusions:

Although femoral syngeneic allografts yielded the largest pre-implantation grafts, this did not translate into larger fusion mass volumes eight weeks later, compared to iliac crest grafts. Interestingly, femoral allografts showed lower rates of solid fusion, via manual palpation, than both iliac crest autograft and allograft groups. Preliminary in vitro assays suggest that this difference is associated with an increased frequency of CFU-F forming mesenchymal progenitor cells in the iliac bone marrow compared to femoral bone marrow. As in previous studies, CT fusion scores did not necessarily correlate with manual palpation fusion scores.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577au

A047: The Effects of Topical Intraoperative Administration of Vancomycin or Tobramycin on Fusion Rates in a Rat Model

Abstract

Introduction:

Local intraoperative use of antibiotic powders in spinal fusion surgery, particularly vancomycin, has become an increasingly common prophylactic measure in an attempt to reduce rates of post-surgical infection. While some clinical studies have suggested that the use of vancomycin in spinal fusion procedures is safe and may reduce the rate of infection, localized intraoperative use of vancomycin powder remains controversial. More importantly, the effects of localized antibiotic delivery on spinal fusion outcomes remain unclear. We thus aim to examine the effects of local intraoperative delivery of vancomycin powder and tobramycin powder, an antibiotic commonly used in orthopaedic bone grafting surgeries, in a rat model of posterolateral intertransverse process lumbar fusion.

Materials and Methods:

Single-level (L4-5) bilateral posterolateral intertransverse process lumbar spinal fusion surgery was performed on 60 female Lewis rats (6-8 week old) using syngeneic iliac crest allograft mixed with the clinical bone graft substitute Vitoss (Stryker) and varying concentrations of antibiotics. More specifically, five experimental groups were studied: [G1] low concentration (14.3 mg/kg) vancomycin (n = 12); [G2] high concentration (71.5 mg/kg) vancomycin (n = 12); [G3] low concentration (28.6 mg/kg) tobramycin (n = 12); [G4] high concentration (143 mg/kg) tobramycin; and, [G5] controls with no antibiotics (n = 12). Eight weeks postoperatively, fusion score and fusion volume were evaluated via microCT analysis (CT scoring per side: 2 = robust fusion; 1 = some narrowing of fusion mass; and, 0 = discontinuity of fusion mass; total score = average of sum of both sides), and manual palpation and histology were performed.

Results:

Preliminary microCT results revealed that the high-dose vancomycin group [G2] exhibited a significantly lower fusion score and fusion mass volume than controls (preliminary fusion scores: [G1]1.8, [G2]1.2, [G3] 1.6, [G4] 3.0, and [G5] 2.3, respectively, P = .045; preliminary fusion mass volumes; [1]20.7, [2]15.5, [3]22.9, [4]34.9, and [5]31.5 mm3, respectively, P = .002). Manual palpation and histological analysis are currently being performed.

Conclusions:

Preliminary data suggest that the intraoperative local application of vancomycin at supraphysiological doses may have detrimental effects on spinal fusion. The results of this study potentially indicate that caution is required when considering the amount of intraoperative vancomycin powder to employ when conducting spinal fusion surgery in certain patient populations. Future clinical studies examining the effects of vancomycin dosage on fusion rates would thus be of great interest.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577av

A048: Effect of Oxy133, an Osteogenic Oxysterol, and rhBMP2 on New Bone Formation in Rat Posterolateral Fusion Model

Abstract

Introduction:

Oxysterols play an important role in inflammation, apoptosis, cell differentiation and other processes. Recent studies demonstrated that several oxysterol analogues including Oxy133 promote osteogenic while inhibiting adipogenic differentiation of progenitor cells, and simulate cranial bone regeneration and solid fusion in animal models. The aim of our study was to determine the effect of Oxy133 and rhBMP2 on fusion rates and new bone formation in a rat posterolateral fusion (PLF) model. Furthermore, we examined whether Oxy133 could inhibit the adipogenesis that is often present in rhBMP2 induced fusion.

Materials and Methods:

Sixty four male Lewis rats underwent PLF at two levels L3-4 and L4-5 with control vehicle, Oxy133 and/or rhBMP2. All animals were randomly divided into 8 groups based on the test compound that they received: control (vehicle –DMSO), low dose rhBMP2 (0.5 µg), high dose rhBMP2 (5 µg), rhBMP2 (0.5 µg) plus Oxy133 (20 mg), rhBMP2 (5 µg) plus Oxy133 (20 mg), high dose Oxy133 (20 mg), low dose Oxy133 (5 mg), and rhBMP2 (0.5 µg) plus Oxy133 (5 mg). Eight weeks after surgery animals were euthanized and L2-L6 segments were harvested. In each group, fusion rates were assessed with manual palpation and plain radiographs. Bone parameters including tissue volume (TV), bone volume (BV), BV/TV ratio, trabecular thickness and separation were measured using microCt. Histology was used to evaluate adipogenesis.

Results:

No fusion was observed in the control group. Based on the manual palpation, 100% fusion was observed in all groups except low dose rhBMP2 group (69%). Based on X-rays 100% fusion was observed in groups: high dose rhBMP2 (5 µg), low dose Oxy133 (5 mg), and rhBMP2 (0.5 µg) plus Oxy133 (5 mg). For other groups fusion rates were between 95-97%, except for the low rhBMP2 group (28%). We observed similar values in BV/TV ratio at L3-4 when Oxy133 groups were compared to rhBMP2 groups alone (44.62%, high Oxy133 vs. 41.47%, high rhBMP2; and 47.18%, low Oxy133 vs. 54.98%, low rhBMP2). Trabecular thickness was slightly lower in Oxy133 groups compared to rhBMP2 (118.44 µm for high Oxy133 vs. 122.39 µm for high rhBMP2; and 123.51 µm for low Oxy133 vs. 135.74 µm for low rhBMP2). At the same time trabecular separation was lower in Oxy133 groups compared to rhBMP2 groups. For groups where Oxy133 and rhBMP2 were used together BV/TV ratio was 40.19%-46.33% and trabecular separation 342.5 µm -405.13 µm. Similar trends in bone parameters were observed at L4-5 level. Fusion masses with high dose Oxy133 had significantly less adipocytes than rhBMP2 groups that showed robust adipocyte formation.

Conclusions:

In our study both low dose and high dose Oxy133 produced solid fusions with bone densities similar or higher than in the BMP2 groups. High dose Oxy133 group had significantly less adipocytes than high or low dose rhBMP2 groups. Furthermore, high dose Oxy133 was able to significantly inhibit high dose BMP2 induced adipogenesis when combined together. Consistent with previous reports, our preliminary findings suggest that Oxy133 has a significant potential as an alternative to rhBMP2 in spine fusion.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577aw

Tumor 1
A049: Patterns of Failure of Fixation In Metastatic Spinal Tumour Disease

Abstract

Introduction:

Spinal column is the commonest site for osseous metastasis. Indications for surgery includes neurologic deficit, obvious or impending instability and/or intractable pain; rarely local tumour control. Patients with spinal metastases have a median survival of 10months and effective palliation of symptoms is principle clinical objective. Many studies have focused on decision making, surgical management and postoperative complications, few focusing on the failure of fixation (FOF) and factors leading to it. This study presents the results of patterns of FOF in metastatic spine tumour surgery (MSTS), clinical presentation before surgery, after failure and factors leading to failure.

Methods:

This is a retrospective study involving 165 patients undergoing MSTS in a tertiary referral institution between 2005-2015. Data were collected from case notes/hospital electronic records and radiological investigations Centricity Web. Radiological data included SINS score, type of lesion (lytic, mixed, sclerotic, none) and levels of fixation. Surgical data included minimally invasive surgery or open fixation & revision after FOF, levels and type of stabilisation. FOF was defined as breakage of the rod or screw, screw back out or cut out, lysis around the screw, increase in angular deformity, reduction in anterior column height, tilting or subsidence of anterior cage. The endpoint of the evaluation was up to last follow-up or death. The level of fixation was considered as anchor in a vertebra (anterior or posterior) by spine implants. Construct length was categorised as short (1-7 level), intermediate (8-12) or long (>12). Vertebra within the construct without anchor was considered as a level. We excluded patients with previous spine surgery, infection of implant leading to failure, survival <30 days post-op and/or age <18yrs.

Result:

Out of 165 patients, 15 died in <30 days postoperation and 12 lost to follow-up, leaving 138 for final analysis. Lung (23.2%) was the most common primary followed by breast (16.7%). Most common symptoms on presentation were instability pain followed by weakness associated with pain. The average follow-up was 11 months (1-92months). FOF was found in 26.8% (37/138). The most common failure was asymptomatic change in angular deformity 86.5% (32/37), back out 5%(2/37), cut out 5% (2/37), lysis 8%(3/37), cage tilt 2.7%(1/37), All FOF cases were recorded in the SIN score range of 7-14, 54% of the patient with FOF had SIN score >9, while no failure was noticed in patients with SIN score <7. Only 4 cases required revision of fixation, who presented with progressive neurological deficit & pain; and were associated with back out or cut out of screw in adjacent disc space with subcutaneous prominence of the screw head. One patient with anterior column reconstruction develops an increase in angular deformity which was resultant of the cage insertion in diseased body.

Conclusions:

We conclude that most of FOF cases showed increase in angular deformity and reduction in anterior column height. Most of the patients with increased angular deformity or loss of height were associated with SIN score >7. Most are asymptomatic and do not require revision though it may be the early sign of the failure of construct.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577ax

A050: Symptomatic Spinal Metastasis: A Systematic Literature Review of the Preoperative Predictive Factors for Survival, Neurological, Functional and Quality of Life Outcomes in Surgically Treated Patients

Abstract

Introduction:

While several clinical prediction rules (CPRs) of survival exist for patients with symptomatic spinal metastasis (SSM), these have variable predictive ability and there is no recognized CPR for health related quality of life (HRQoL). We undertook a critical appraisal of the literature to identify key preoperative predictive factors of clinical outcomes in patients with SSM who were treated surgically. The results of this study could be used to modify or develop new CPRs.

Material and Methods:

Seven electronic databases were searched (1990 – 2015), without language restriction, to identify studies that performed multivariate analysis of preoperative predictors of survival, neurological, functional and HRQoL in surgical patients with SSM. Individual studies were assessed for class of evidence and the strength of the overall body of evidence for each factor was evaluated using GRADE.

Results:

Among 4,818 unique citations, 17 were included, all were rated Class III and focused on survival, revealing a total of 46 predictive factors. The strength of the overall body of evidence was very low for 39 and low for 7 predictors, with the latter including 3 negative predictors for all types of primary tumors (radioresistant primary tumor, Charlson comorbidity index score ≥2 and non-ambulatory status) and 4 for breast cancer (shorter time from cancer diagnosis to surgery, emergency hospital admission, primary with undifferentiated histologic grade and negative progesterone receptors).

Conclusion:

The quality of evidence for predictors of survival was at best low. We failed to identify studies that evaluated preoperative predictive factors for neurological, functional, or HRQoL outcomes in surgical patients with SSM. Further high-quality evidence is needed to accurately estimate predictor effect sizes, for patient education, surgical decision-making and development of CPRs.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577ay

A051: Stereotactic Body Radiotherapy followed by Surgical Stabilization for Patients with Unstable Spinal Metastases: First-in-Man Study according to the IDEAL Recommendations

Abstract

Introduction:

Standard treatment of unstable vertebral metastases consists of stabilizing surgery, followed by external beam radiotherapy, a minimum of two weeks later. This two-week interval, required for wound healing, delays the time before radiotherapy-induced pain relief and local tumor control can be achieved. Furthermore, multiple hospital visits are needed for most radiotherapy fractionation schemes and moreover, currently 30-40% of the patients experience incomplete pain relief. From the patient’s perspective, an alternative treatment strategy that would lead to better and faster pain relief while requiring less hospital visits would be highly desirable. Stereotactic body radiotherapy (SBRT) may be used in combination with surgical stabilization to increase the local dose on the spinal metastasis for better response while actively avoiding irradiation of the surgical area to prevent disturbed wound healing. Therefore the aim of this phase I/II study is to assess the safety and feasibility of combining single fraction SBRT followed by pedicle screw fixation within a 48-hour window for the treatment of painful unstable spinal metastases.

Materials and Methods:

The present study will be conducted according to the IDEAL recommendations, a framework for systematic evaluation of complex interventions consisting of five stages: Innovation, Development, Evaluation, Assessment and Long term evaluation. A total of 13 patients will be included in two stages. In stage 1, three patients will be included in whom the new procedure will be tested first. In stage 2, ten patients will be included, the main focus is technical feasibility and safety. Information on demographic and clinical characteristics, treatment, toxicity (according to the CTCAE4.0 within 60 days), complications and survival will be systematically collected. Patients with painful spinal metastases from a solid tumor needing surgical stabilization will be included. SBRT is simulated first on a planning CT to deliver a dose of 18 Gy on the metastasis and 8 Gy on the rest of the vertebra while actively avoiding exposure to the posterior surgical area. After SBRT is performed, patients will undergo surgical stabilization within 48 hours according to routine practice.

Results:

The first ten patients, five males and five females, have successfully been treated according to this new treatment protocol. A posterior approach was used for all surgical procedures, with two conventional open and eight percutaneous procedures. The mean operating time was 82 minutes (±SD33) with a median blood loss of 50 millilitres (range 50-300). The median length of hospital stay was 5 days. None of the patients experienced a wound complication or other study related complication. One patient suffered a grade 3 surgery related complication, which resolved after re-operation. Combination of the procedures was feasible and the patients experienced no discomfort during the SBRT procedure before stabilization of the spine. We expect to be able to present the results of all 13 patients at the time of the conference.

Conclusion:

The preliminary results suggest that the combination of SBRT and surgical stabilization within 48 hours is safe and feasible. Hereby a new and promising one-stop treatment strategy may have been developed for a difficult to manage, vulnerable patient category.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577az

A052: Selective Endovascular Embolization in Pediatric Patients with Hyper-vascular Mono-segmntal Thoracic and Lumbar Spine Tumors

Abstract

Introduction:

The hyper-vascular component in spinal tumor significantly increase technical difficulties and post-op complications risks, including perioperative blood loss which could reach a few liters. The selective vascular embolization is effective to decrease blood loss in adult patients, but it effect is not completely clear in pediatric patients.

Material and Design:

13 patients aged from 4 till 16 yrs were investigated during 2005 – 2016 period due to suspicion on monovertebral spinal lytic tumors with a hyper-vascular component in its structure. 11 patients were included into study due to the cervical (1), thoracic (6) and lumbar (4) vertebrae bodies lesions; 2 ones were excluded because of isolated neural arch affect. The back pain was the prominent sign of tumors in all patients; motors or bladder and bowel disorders were in 3. Bone scan with Tс99 was in all cases, the vascular component was suspected by MRI. ABC was diagnosed initially in 5 patients, after surgery one of them was identified as high differentiated low grade angiosarcoma; cavernous hemangioma was in 4, one more case diagnosed as hemangiogenic variant of Gorham-Stout disease («angiogenic octeolysis”). Percutaneous pre-op trepan-biopsy was in 8/13 cases, cytology was equal with post-op histology in 4 (50%). Pre-op selective angiography done in 7/13 patient followed by embolization in 6. The embolization was not performed in one case because of the anastomosis between the tumors’ and spinal cord vessels. The embolization-related complication were not in our series. The blood loss volume was estimated as at the end of surgery as 24-hour after it. The blood loss volume estimated according to hematocrit (Ht) rate due to the Moore’s formula. Two groups of patients (with and without embolization) were compare according to statistic Mann-Whitney U-test with P ≤ .05 significance level.

Results:

Embolization had reached complete disappearance of clinical signs in patient with Gorham-Stout syndrome: the indication for surgery was cancel, the patient continued effective bisphosphonates treatment next 3 years and was cancel from the final analysis. 5 patients with pre-op embolization and without it underwent surgery with complete vertebral body replacement. In was not find significant different in blood loss between compared groups which was counted as 29% and 24% of the volume of circulated blood (P ≥ .05, Mann-Whitney U-tests 12.5. The early post-op wound infections was in 2 cases (one in each group), both in patients with operative blood loss exceeded 1000.0 ml.

Conclusions:

It has detected that perioperative blood loss in pediatric patients with spinal tumors included hyper-vascular component in its structure significantly less than in adult patient. It wasn’t confirmed the dependence of perioperative blood loss in such patients from the fact of pre-op endovascular embolization. Perhaps, this negative result could connected with as a small number of cases as a more detailed hemostasis in non-embolized patients. From other side, it is detected that the duration of surgery was shorter and visual control was significantly better in patients after embolization.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577ba

A053: Retrospective Analysis of Preoperative Embolization of Patients with Primary and Secondary Spinal Tumors

Abstract

Introduction:

Investigate the safety and efficacy of transarterial embolization in patients with hypervascular spinal metastases and primary tumors before surgical resection.

Material and Methods:

Thirty nine patients with spinal metastases and primary tumors underwent angiography and preoperative transarterial embolization with spherical particles, coils and the liquid cohesive composition before surgical resection. The following parameters were evaluated: types of tumor, sex, time interval between embolization and surgery, the influence of these parameters on intraoperative blood loss, surgical content, safety for the patient.

Results:

Intraoperative blood loss in patients undergoing embolization was up to 500 mL - 29 (74.4%), to 1000 mL - 2 (5.1%), to 2000 mL - 3 (7.7%), 2000 mL – 5 (12.8%). Average value of blood loss for RCC 546.2 mL., for other metastases – 373.5 mL., for primary tumors – 2488.8 mL. There have been no in-hospital mortality related with the intraoperative blood loss. All patients received standard supportive care, emergency blood transfusion was not performed. Three (7.7%) patients after endovascular interventions had complications in the form of temporary neurological deficit, fifteen (38.5%) had postembolization syndrome.

Conclusion:

In the embolization group, intraoperative blood loss was correlated with type of tumor and type of surgical resection. Preoperative embolization is safety and effectively to decrease intraoperative blood loss for patients with hypervascular spinal tumors.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577bb

A054: Surgical Treatment of Spinal Cord Intramedullary Tumors in Adult

Abstract

Introduction:

The incidence of intramedullary tumors is much lower compared to brain intraparenchymal tumors. Surgery of spinal intramedullary tumors has own tricks during approach and removing process. The Burdenko Neurosurgical Institute has a well-established practice of surgical treatment of intramedullary tumors.

Materials and Methods:

Burdenko Neurosurgical Institute has experience of treatment more than 1000 patients with spinal intramedullary tumors of all ages. In this research we report results of spinal department for treatment of 385 adult patients with spinal intramedullary tumors between 2000 and 2016 years. We identified following histological types: ependymomas, astrocytomas, hemangioblastomas and other types. All patients underwent microsurgical tumor resection with application of ultrasound suction device and electrophysiological monitoring. In some cases, we used a metabolic navigation from 5-aminolevulinic acid to precisely identify the borders of astrocytomas (Grade II, III, IV). This allowed us resections tumors more radically with minimal postoperative deficits. Novalis and Cyber Knife were used as a treatment options for patient requiring. McCormick scale was used for evaluation neurological status.

Results:

Histological distribution were: 57% – ependymomas, 18% – astrocytomas, 35 10% – hemangioblastomas, and 15% had other histological type of tumors (cavernous malformation, glioblastomas, cancer metastasis and other). Follow-up period was one year, and the post-surgery recovery period took 3 to 6 months. Among the 320 patients under analysis, 33% showed some neurological improvement, 51% had no change, and 16% was revealed neurological deficiency.

Conclusions:

Using technology of metabolic navigation and electrophysiological monitoring simultaneously allows more radical resection spinal intramedullary tumors with less complications. Radiosurgical treatment of intramedullary tumors allows preventing recurrence.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577bc

Trauma Cervical 1
A055: An Economic Case for the Surgical Treatment of Type-II Odontoid Fractures in the Elderly: A Markov Cost-Utility Analysis based on the Prospective AOSpine Geriatric Odontoid Fracture Study

Abstract

Introduction:

Type-II odontoid fractures are the most common cervical fractures encountered in the elderly, with an overall incidence that appears to be rising. Substantial uncertainty continues to surround optimal management of these injuries; while non-operative treatment is associated with a high rate of non-union, surgery is more costly and may be associated with high complication rates in this age group. To provide further evidence on this topic, we performed a value based assessment comparing costs and health gains between these treatment strategies.

Material and Methods:

We constructed a Markov cost-utility model, with a life-long time horizon, comparing quality-adjusted survival and costs of surgical vs. non-operative treatment (external orthosis), from the perspective of the payer, for the base case of a 75 year-old person with a type-II odontoid fracture. Mean utility values, corresponding to the health states of interest, were calculated from primary data (SF-6D scores) prospectively collected during the AOSpine GOF Study. Probability rates for mortality, complications, failure/fusion were estimated based on a systematic review of the literature. Per patient treatment costs, presented in 2016 US dollars, were obtained from the Healthcare Cost and Utilization Project, National Inpatient Sample, averaged over a 7 year period (2003-2010). Incremental Cost Effectiveness Ratios (ICERs) were evaluated relative to a Willingness to Pay (WTP) threshold of 50,000USD/QALY. One- and two-way sensitivity analyses were performed to identify threshold values for age, cost, utility and probability values. Finally, probabilistic sensitivity analysis, using Monte Carlo Simulation with 1,000 sample iterations, was performed to generate ICER scatterplots and cost-effectiveness acceptability (CEA) curves.

Results:

Over a lifetime, as compared to non-operative treatment, surgery was associated with an average gain of an additional 0.81 QALYs and additional costs of 12,788USD, resulting in an ICER of 15,725USD/QALY for the base case analysis. With increasing age, surgery became less cost-effective, with age 96 representing the threshold beyond which the ICER exceeded the WTP threshold (ICER at age 85:26,069USD/QALY; ICER at age 95:46,049USD/QALY). Results were also found sensitive to variation in year 1 post-op mortality rates, with surgery becoming less cost-effective as surgical mortality increased and as non-operative treatment morality decreased (Figure 1). Model results were less sensitive to variation in costs or fusion and complication rates for each strategy. Probabilistic sensitivity analysis revealed surgery to be the most cost-effective strategy in 79.3% of the 1000 iterations sampled, as depicted in the ICER scatterplot (Figure 2). Generation of CEA curve demonstrated surgery to the preferred strategy above a WTP threshold of 20,000USD.

Conclusion:

Surgical treatment for type-II odontoid fractures in the elderly appears to provide better value with respect to costs and health gains compared to non-operative management with external orthosis. However, surgery becomes less cost effective with increasing patient age and increasing probability of early postop death. This implies that while surgery is likely to be the preferred approach for the younger healthier patient, conservative management may be more appropriate for the older patient with a higher probability of short-term mortality. Further studies are needed to confirm the findings presented here.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577bd

A056: Bicortical Facet Screws as a New Option for Posterior C2 Fixation: Anatomical Study and Clinical Experience

Abstract

Introduction:

Many different techniques of C1-C2 arthrodesis have been developed and screw and rod constructs are actually the most commonly used. However, C2 pedicle or isthmic screw placement is technically demanding and carries the risk of neural and vascular injury. The inferior articular process (IAP) of the axis can be a safe alternative for screw placement in patients with bone or vascular variants of C1-C2 anatomy. We report the results of a CT study of C2 IAP anatomy, which can provide useful parameters for screw placement. We also present the preliminary clinical experience of 25 patients operated with this technique.

Material and Methods:

Morphological study: 50 CT angiographies of the vertebral arteries (VA) were used for this study, and therefore 100 IAP were considered. We measured on the axial and sagittal planes the length of the facet, the distance between the anterior cortex and the VA and the distance between the screw entry point and the VA. We also measured the angle between the sagittal plane passing through the entry point and the external tangent line of the VA. Clinical report: 25 patients (mean age 63) were treated with C2 IAP screws at the Spine Surgery Department of the University Hospital in Lyon, France, from January 2014 to Jun 2016. The screw entry point was located in the middle of the C2 IAP, and bicortical screws were inserted with a perpendicular trajectory on the sagittal plane and a lateral inclination of 15-20° on the axial plane.

Results:

Morphological study: the mean length of C2 IAP was 12 ± 2 mm, the mean distance between the anterior cortical layer and the VA was 5.2 ± 1,4 mm, and the mean distance between the screw entry point and the VA was 15.7 ± 1.9 mm. The mean angle we found was 0.2 ± 5.3°, with minimum and maximum values of −13.5° and 14.5° respectively. Clinical report: 13 women and 12 men were treated with C2 IAP screws. 15 of the 25 patients presented post-traumatic C1-C2 instability, 7 patients presented degenerative disease, 1 patient was treated for pseudoarthrosis, 1 for OPLL and 1 for rheumatoid arthritis. There was no post-operative neurological aggravation in this group. All the screws were correctly positioned and there was no VA injury. Among the 5 patients with post-operative complications, only the 3 wound infections were directly related to surgery. No mechanical complication (screw migration or pull-out) was noted post-operatively.

Conclusion:

C2 screw placement carries the risk of VA injury, and some anatomical condition such as narrow pedicles can increase this risk or even impede the procedure. IAP screws represent a safe alternative option for C2 fixation in some cases, and the morphological and clinical data we present in this study demonstrated that it is a feasible procedure.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577be

A057: Halo Vest Immobilization and Surgical Fusion for Pediatric Cervical Spine Injuries

Abstract

Introduction:

Treatment options for pediatric cervical injuries include external immobilization and surgical fusion. Differences in the operative vs. non-operative treatment outcomes of different cervical injury locations (atlantoaxial vs. subaxial) has not been adequately addressed among pediatric patients. In this study, we performed a retrospective analysis using the Nationwide Inpatient Sample (NIS) database to compare complication rates for cervical injuries after external fixation or spinal fusion in the pediatric population.

Material and Methods:

Patients under the age of 18 with a discharge diagnosis of cervical spine fracture without spinal cord injury or cervical spine subluxation were identified in the NIS database. Patients who were treated with internal fixation or external immobilization between 2002-2011 were included for analysis. Patients who did not undergo treatment and patients with unspecified fracture level were excluded. Discharge weights were applied and used to produce national estimates. Outcome data included length of stay, in-hospital mortality, discharge disposition, total hospital charges, and development of in-hospital complications.

Results:

A total of 2,878 pediatric patients with cervical spine injury were identified after application of discharge weights; 1,462 patients (50.8%) with atlantoaxial injury and 1,416 (49.2%) with subaxial spine injury. There were 1,037 atlantoaxial injury patients (70.9%) treated with external immobilization and 425 patients (29.1%) who underwent internal fixation. Significant differences between groups included total charges ($73,786 ± $107,108 for immobilization and $98,158 ± $86,548 for surgery, P = .040), and development of at least one complication (1.9% for immobilization and 6.8% for surgery, P = .029). Mortality (P = .363), length of stay (P = .221) and non-routine discharges (P = .106) were not different between groups. Among patients with subaxial injuries, there were 542 patients treated with external immobilization (38.3%) and 874 patients treated with surgery (61.7%). When comparing external immobilization to surgery for suabxial injury patients, there were no significant differences in sex (68.2% male vs. 65.4%, p = 0.622), primary payer (P = .493), injury mechanism (P = .234), length of stay (6.4 ± 6.7 days vs. 5.5 ± 5.2, P = .196), mortality (P = .430), non-routine discharges (P = .117), complication occurrence (P = .334), or total charges ($69,042 ± $83,614 for external immobilization vs. $83,123 ± $66,491 for surgery, P = .142). Patients with subluxation alone were treated more often with surgical fusion than with external immobilization (2.2% vs. 1.2%, P < .001).

Conclusion:

The management of cervical spinal injuries in pediatric patients must be informed by the location of the injury. In patients with atlantoaxial injuries, the lower overall complication rate and decreased cost may warrant initial consideration of external fixation for treatment. Complication rates for subaxial injuries did not vary by treatment in this study, leaving both external immobilization and surgical fusion as two viable options for treatment. These results will help guide clinicians in their treatment decisions and support more cost-effective methods for managing cervical injuries.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577bf

A058: Trends in Incidence and Treatment of Odontoid Fractures

Abstract

Introduction:

There is little information on the incidence of odontoid fractures in recent years and on the current treatment patterns amongst spine surgeons for these fractures. The purpose of the present study was to elucidate recent trends in surgical and nonsurgical treatment of odontoid across patient demographics.

Material and Methods:

Patients diagnosed with an odontoid fracture from 2005 to 2011 were identified in a national database of records from Medicare (PearlDiver Patient Record Database) using International Classification of Diseases, Ninth Revision (ICD-9) and Current Procedure Terminology (CPT) codes. Treatment groups were stratified as operative or nonoperative. The operative group consisted of fusion and fracture fixation. The nonoperative group included all other treatment modalities including cervical collar and halo vest. Results were analyzed by year, age group, gender, and geographic region.

Results:

There were a total of 56,230 odontoid fractures identified from 2005 to 2011. There was a 26.2% increase in fracture incidence over this period (P < .0001). The incidence of odontoid fractures increased with each successive age group with a 6.8-fold increase in patients over age 85 years compared to those under age 65 years (P < .001). Incidence was higher in females than males (P < .001) and in the Midwest compared to all other geographic regions (P < .001). There was a trend towards increased operative treatment over the study period from 6.7% in 2005 to 8.0% in 2011 (P < .001). Operative treatment was more common in males (12.0%) than in females (7.1%) (P < .001). Rate of surgery was highest in the West (10.9%) followed by the South (9.3%), Midwest (8.9%) and the Northeast (8.1%) (P < .001). Surgical treatment was most common in the 65-69-year and 70-74-year age groups (12.4% and 12.6% respectively) and least common in the >85-year age group (5.4%).

Conclusion:

Incidence of odontoid fractures steadily increased over the study period. Patients greater than 85 years were at the highest risk with a nearly 7-fold increase in patients younger than 65 years. There was a slight increase in the overall rate of surgical treatment over the study period; however, nonoperative treatment remained the dominant treatment modality across all years and patient groups. Operative treatment was most common in patients between 65- and 74-years-old and significantly less common in patients over 85-years-old. Although females accounted for a greater percentage of odontoid fractures, males were more likely to be treated operatively. The information on current trends in incidence and treatment of odontoid fractures may serve as a reference for future studies in light of recent evidence that operative treatment may be more cost-effective than nonoperative treatment in select patients.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577bg

A059: Application of AOSpine Subaxial Cervical Spine Injury Classification System as Predictor of Injury Severity and Neurological Outcome in Simple and Complex Cases

Abstract

Introduction:

Cervical spine injury classification systems should be simple, easy to remember, related to injury severity, a guide surgical planning, reliable, and a predictor of outcome in clinical settings. Neither the mechanistic classification of Allen et al nor the conceptually simple classifications of TJ Harris et al have been capable of satisfying those objectives. We investigated whether the AOSpine subaxial cervical spine classification system predicted injury severity and neurological outcome.

Material and Methods:

We analyzed relevant clinical, imaging (preoperative CT, MRI, and postoperative MRI), management, and 6-month follow-up ASIA motor score of 92 AIS grades A-C patients with subaxial cervical spine fractures and spinal cord injury. Subaxial cervical spine injuries were classified according to the AOSpine Injury Classification System: A4 fractures are vertebral body fractures with both end-plates protruding into the spinal canal; B2 injuries are hyperflexion with intact anterior elements; B3 injuries are distraction injuries with intact posterior elements and no translation; and C type injuries are fracture dislocations with translation in any axis (X, Y, or Z) with disruption of the discoligamentous complex. We correlated morphology class to age, injury severity score (ISS), follow-up ASIA motor score (AMS), intramedullary lesion length (IMLL), and AIS grade conversion at 6 months post injury.

Results:

Mean age was 39.3, 83 patients were male, and 69 patients were injured during an automobile accident or following a fall. AOSpine Class was A4 in 8, B2 in 5, B2A4 in 16, B3 in 19, and C in 44 patients. Mean ISS was 29.7 and AMS was 17.1 (A4 = 17.6, B2A4 = 13.9, B2 = 9.8, B3 = 21.8, and C = 18 NS). AIS grade was A in 48, B in 25, and C in 19 patients. IMLL on postoperative MRI was 72 mm [(SD = 37.8): A4 = 68.1 (SD = 25.8); B2A4 = 86.5 (SD = 43.1); B2 = 59.3 (SD = 32.2); B3 = 46.8 (SD = 21.7); and C = 79.9 (SD = 39.1)]. At a mean follow-up of 6 months, mean ASIA motor score was 39.6 [SD = 31.9(A4 = 41.3, B2 = 54.3, B2A4 = 36.2, B3 = 53.9, and C = 33.1)]. Compared to Class B3 patients (simple hyperextension with intact posterior arch and no translation), Class C patients (with translation in any plane) were significantly younger (P < .0001), had longer IMLL (P < .002), and were less likely to have AIS grade conversion to a better grade (P < .02).

Conclusions:

AOSpine subaxial cervical spine injury classification system successfully predicted injury severity (longer IMLL) and chances of neurological recovery (AIS grade conversion) across different class subtypes.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577bh

A060: Complex Type II Odontoid Fractures: Our Management

Abstract

Introduction:

Type II odontoid fracture is the most common fracture of CVJ which is often treated surgically. Incidence of non-union is high in cases managed conservatively due to complex nature of these fractures especially type IIA. Anterior odontoid screw fixation is useful in preserving the movements at C1-C2 whereas fixed arthrodesis achieved through posterior approaches lead to loss of motion at C1- C2. Anterior odontoid screw fixation is traditionally contraindicated in type IIA odontoid fractures, unstable odontoid fractures (ruptured transverse ligament, associated Hangman’s fracture or AAD), difficulty in screw placement (severe angulation/translation, anterior oblique fracture line, body habitus) and in cases with high risk of non-union (displaced and irreducible fractures, osteoporosis).

Material and Methods:

We are reporting 22 patients with type II odontoid fractures. All the patients were surgically treated with anterior odontoid screw. In 4 cases, of which 3 cases, due to severe displacement/angulation and irreducibility of the fracture fragment and 1 case due to difficult trajectory in screw placement, anterior odontoid screw fixation was thought to be contraindicated. Pre operatively, patients underwent X-ray, NCCT and MRI of CVJ to classify the fracture, to know the status of ligaments and rule out other injuries of the cervical spine. We attempted anterior odontoid screw fixation to preserve the neck rotation at C1-C2. In 3 cases out of 4 complex cases, skeletal traction was applied in extension. However, the fracture fragments were not reducible. So we performed anterior odontoid screw fixation (which is otherwise contra indicated) with trans-oral continuous controlled pressure over the posterior pharyngeal wall to realign the fracture in 2 cases. In one case, as the realignment was not possible by pressure over the posterior pharyngeal wall, via transoral - trans pharyngeal microscopic approach, fracture fragment was reduced. All trans oral procedures were done under neuromonitoring. Out of 4 complex cases, in one case of ankylosing spondylitis due to difficult trajectory in screw placement, projecting osteophytes over C2 and C3 were drilled and anterior odontoid screw fixation was done. All patients were followed up till 6 months post operatively with x-rays. In all the 4 complex cases, CT scan was done at 3 months post op.

Results:

21 patients had successful fusion in the follow up and maintained normal cervical rotation. In one patient among the 4 complex cases, due to failure of alignment and screw back out after anterior odontoid screw fixation, a second procedure was planned and posterior C1-C2 fusion was done.

Conclusion:

The rotation at C1-C2 is most important movement at CV junction for human daily activities especially in young individuals. Every attempt should be made to reduce the fracture fragment to do anterior odontoid screw fixation before converting it to posterior fusion. Understading the mechanism of injury and fragment mobility helps in changing contraindication of anterior odontoid screw fixation in patients with complex odontoid fractures to an indication. However, experience & close follow up helps in preserving the C1-C2 rotation.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577bi

Novel Technologies and Diagnostics
A061: 9.4 T MRI Complements the Pfirrmann Grade through Better Differentiation of the NP/AF

Abstract

Introduction:

MRI is the gold standard for visualization of intervertebral disc (IVD) degeneration. The 9.4 T MRI provides superior resolution and anatomical detail, however it has not yet been applied to the study of lumbar degenerative disc disease. The Pfirrmann1 and the Modified Pfirrmann2 grades, developed on 1 T and 1.5 T MRI respectively, do not take into consideration much of the detail now visible with the 9.4 T MRI. An updated and enhanced MRI grading system of IVD degeneration is therefore required. We developed a 9.4 T MRI grading system accounting for the enhanced definition of the annulus fibrosus (AF) lamellar architecture, nucleus pulposus (NP) and the NP/AF differentiation. We further developed a NP/AF distinction score to investigate whether this would correlate with the 3 T Pfirrmann grade. Additionally, we utilised a simple IVD degeneration classification accounting for the Pfirrmann grade and the new 9.4 T MRI grading system.

Materials and Methods:

3 T and 9.4 T MRI (Agilent Technologies) lumbar spine studies were obtained at necropsy of 90 IVDs in 18 ewes involved in an IVD cellular therapy study. Disc degeneration was initiated in the ewes six months prior to necropsy via surgical intervertebral disc injury. The newly developed 9.4 T MRI grading system, evaluating for the AF signal intensity, NP signal intensity, AF lamellae structure, NP/AF differentiation and hypointensities in AF and NP, was applied to the 9.4 T T2 MRI images. Pfirrmann grades were calculated for the 3 T and 9.4 T MRI studies for comparison. A NP/AF distinction score was calculated on the 9.4 T MRI and compared with the overall 3 T Pfirrmann grade.

Results:

The 9.4 T MRI images demonstrated exceptional resolution and anatomical detail of the intervertebral discs. The 3 T and 9.4 T MRI Pfirrmann grades demonstrated a very strong correlation (R2 1). The NP/AF distinction score also demonstrated a significant correlation with the overall 3 T Pfirrmann grade (R2 0.92, P < .0001). The new 9.4 T MRI grading system did not demonstrate a strong correlation with the 3 T or 9.4 T Pfirrmann grades, R2 0.78 (P < .0001) and R2 0.77 (P < .0001) respectively. However, when the discs were stratified into mild degeneration (Pfirrmann grades 1-2; 9.4 T MRI grades 1-4), moderate degeneration (Pfirrmann grade 3; 9.4 T MRI grades 5-7) and severe degeneration (Pfirrmann grade 4-5; 9.4 T MRI grades 8-10), the new MRI grading system correlated very well with the 3 T and 9.4 T Pfirrmann grades (R2 0.92, P < .0001). An assessment of inter-observer and intra-observer reliability demonstrated acceptable levels of agreement.

Conclusion:

The 9.4 T MRI Pfirrmann grade demonstrated a strong correlation with the 3 T Pfirrmann grade, with good inter-observer reliability. The NP/AF distinction score correlated well with the overall 3 T Pfirrmann grades suggesting this could be a potential predictive measure of IVD degeneration. The poor correlation observed between the new 9.4 T MRI grading system and existing Pfirrmann grades likely reflects the wider range of scores possible with the new grading system. The new 9.4 T MRI grading system is a reliable tool that is better able to appreciate the subtle changes in IVD degeneration.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577bj

A062: Horizontal Rod and Band: A Novel Surgical Technique for Isthmic Repair

Abstract

Introduction:

Many techniques are described for the surgical reconstruction of isthmic spondylolisis. Technical difficulties with some constructs have been described (wire breakage and cutting-through-bone with metal wire, bone lesions with directs screwing, difficulty to bend the rod and bone erosion with U-shaped rods under the spinous processess), but the healing of the underlying pseudarthrosis is not always achieved. We describe a new technique of fixation that allows for the application of progressive compression force over the pars interarticularis with a non-rigid device.

Material and Methods:

The surgical technique consists of the following steps: exposure of the pars defect, preparation and bone grafting; positioning of two polyaxial pedicle screws at the lythic vertebra with standard technique; a rod is inserted connecting horizontally the two screws and piercing the interspinous ligament above the lythic vertebra; commercially available sublaminar bands are passed from the right under base of the spinous process of the lythic vertebra, around the left side of the rod, again under the base of the spinous process from left to right and finally connected to the right side of the rod; tensioning of the band results in compression across the reconstruction, providing stability. A 14 year-old male with severe low back pain associated with a L5 isthmic lysis underwent surgical treatment after 10 months of unsuccessful conservative treatment. The case illustrates the technique.

Results:

The intraoperative fluoroscopy and the post-operative X-ray demonstrate reduction of the defect and effective compression provided by the fixation system. The patient was mobilized the day after surgery without a lumbar corset and discharged the following day. Physical activity was restricted for the first 6 weeks post-operatively. The patient presented to clinic at a month and half follow-up referring no lumbar pain during rest or light sports activity.

Conclusion:

The purpose of isthmic reconstruction is to stabilize the vertebral segment in the most anatomical manner with a safe and reproducible technique. Achieving isthmic healing will significantly improve the quality of life of the patient in terms of low back pain allowing for prompt recovery and return to sports activity, as well as reduce the rate of early degeneration of intervertebral disc.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577bk

A063: Intraoperative Neurophysiological Monitoring in Cervical Myelopathy

Abstract

Introduction:

Intraoperative neurophysiological monitoring (IONM) is not used as a routine in spine surgery in many centers, although it is a standard of care in scoliosis procedures. Although there are many papers claiming that IONM is not needed in cervical procedures. Indeed, irreversible changes during IONM are predictive of severe adverse neurological outcomes (level of evidence class A) which is why it is becoming more popular in cervical spine procedures because it seems to be producing better functional result.

Material and Methods:

191 consecutive patients (121male / 70 female; mean age of 60.15, SD = 15.1) who were undergoing cervical spine surgery fpr myelopathy from 2013 -2016 were recruited for the study. Anterior approach 109, posterior approach 82. Total intravenous anesthesia (TIVA) was used in all patients. No muscle relaxant after intubation. IONM was performed by SSEP and TcMEP in all patients.

Results:

IONM warnings were detected in 14 (7.3%) patients. 9/14 in presurgical cervical positioning of the patients (8/14 in posterior approach), all of them recover after repositioning. 3/14 for reversible hypotension. 2/14 during surgical procedure (one of them didnt recover IONM and woke up with severe tetraparesis). TcMEP were more sensitive than SSEP detecting warnings.

Conclusion:

Positioning during cervical procedures is a potentially damaging manoeuvre that may require an adequate neurophysiological monitoring technique in order to prevent damage to the spinal cord and consequently, the development of new postoperative neurological deficits.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577bl

A064: Predictive Accuracy of SurgimapTM Surgical Planning for Sagittal Imbalance: A Cohort Study

Abstract

Background:

Surgical planning to correct sagittal spinal imbalance is recognized as a key component of the surgical strategy, ensuring better patient outcomes. Surgimap is a software designed to simplify surgical planning in patients with adult spinal deformity.

Purpose:

To evaluate the predictive value of surgical planning using Surgimap regarding postoperative sagittal alignment.

Methods:

We conducted a retrospective evaluation of a prospective cohort to compare the predicted sagittal alignment with a Surgimap computer simulation of the surgical correction and real post-operative X-rays. The study involved 40 non-consecutive patients who underwent surgery for sagittal misalignment in a single Orthopedic center between June 2009 and April 2013. Postoperative alignment measured by sagittal vertical axis (SVA) and pelvic tilt (PT) was considered the gold standard. Surgimap prediction of final alignment was considered the test. Planning and postoperative films were classified as properly and improperly aligned. Sensitivity, specificity, and positive and negative predictive values of Surgimap planning [using two different methods of preoperative planning: direct simulation (method A) and simulation after correction of pelvic tilt to 20° (method B)] to detect postoperative improper alignment were calculated.

Results:

Seventeen (42.5%) of 40 patients had proper post-operative alignment. According to method “A” a proper alignment was achieved in 13 patients [S = 76.5%, Sp = 73.9%, RR = 2.93 (95% CI 1.40; 6.12), P < .001]; According to method “B” a proper alignment was achieved in 15 patients [S = 88.2%, Sp = 60.9%, RR = 2.25 (95% CI 1.32; 23.86), P < .001]. Kappa statistics indicate moderate agreement between actual post-operative alignment and computer prediction. In particular, when compared to method “A”, method “B” demonstrates better performance regarding the ability to predict proper postoperative sagittal alignment (Negative Predictive Value -NPV- of method “B” was 88% vs. 81% by method “A”).

Conclusions:

The ability of Surgimap to predict proper postoperative sagittal alignment was excellent (NPV 81% to 88%) in this cohort. Its ability to predict proper alignment was improved by correction of PT to 20° during planning (Method “B”, NPV 88%).

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577bm

A065: Evaluation of Techniques to Determine Rotational Alignment of the Vertebral Body in Minimally Invasive Spine Surgery: A CT Analysis of Lumbar Spine Symmetry

Abstract

Introduction:

Minimally invasive spine surgery relies heavily on fluoroscopic guidance. Rotational alignment of the vertebral body (VB) is typically assessed using two different techniques. The first involves assessment of the pedicles to ensure that they are symmetrical in size and proximity to the lateral wall of the VB. The second method evaluates the position of the spinous process (SP) to ensure it falls in the center of the lateral walls of the VB. The precision of these techniques may be confounded by anatomic variation and deformation of these structures. This paper aims to evaluate the reliability of these techniques by evaluating the symmetry of these structures on CT scan.

Materials and Methods:

One hundred lumbar spine CT scans from patients complaining of back pain, without evidence of scoliosis or spondylolisthesis, were reviewed; a total of 500 lumbar vertebrae. Measurements included pedicle height and width, distance from the pedicle to the lateral wall of the VB and the angle of the SP measured from the perpendicular of a line running through the widest point of the VB. The length of the SP was also measured and these values allowed us to calculate the offset from midline of the tip of the SP as would be seen in an AP fluoroscopic image. Considering the measurement error of a Cobb angle is quoted at 5 degrees, we labeled SP angles less than this as relatively perpendicular to the VB.

Results:

There was no statistical difference appreciated comparing bilateral pedicle height and width or pedicle-lateral wall distance for each VB from L1 to L5. The SP angle was found to deviate relatively equally to the right or left and this varied from level to level even within the same patient. Notably, the deviation of the SP was greater than 5 degrees in 14.4% of the vertebrae. In the L1 body, SP angle was greater than 5 degrees in 12% with the average deviation in these of 5.73 degrees, correlating to an offset of 3.1 mm. L2 SP deviation was greater than 5 degrees only 4% of the time, averaging 6.05 degrees meaning an offset of 4 mm. The L3 the SP deviated 16% of the time averaging 6.36 degrees meaning an offset of 3.7 mm. The L4 SP also deviated 16% of the time, averaging 7.3 degrees with an offset of 3.7 mm. The L5 SP deviated 24% of the time averaging 8.48 degrees meaning an offset of 4.9 mm.

Conclusion:

Our CT guided anatomical study of the lumbar vertebrae shows that pedicle dimensions and pedicle-lateral wall distance are symmetrical and therefore reliable measures of VB rotation. The novel finding is that the SP is not an accurate marker of midline as it may significantly deviate to one side 4-24% of the time by a margin of 3.7 to 4.9 mm. This occurs more frequently as we move caudal in the lumbar spine. Using the SP to determine midline of the VB may lead to misalignment during localization, increasing the risk of medial or lateral breach of the pedicle wall.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577bn

A066: Extra Foraminal Selective Nerve Root Block: A Novel Technique for Management of Lumbar Radiculopathy

Abstract

Introduction:

Selective nerve root blocks (SNRB) play an important role in treating cases with lumar radiculopathy. Traditionally since describing its reported outcomes transforaminal SNRB was being considered as a standard route for lumbar radiculopathy. Technically the transforaminal route of SNRB is a difficult procedure with many reported complications. We here in the study propose a novel technique in SNRB’s.

Material and Methods:

A clinical study of 100 individuals with lumbar nerve root radiculopathy of spinal origin who does not fit into the surgical management category. Nerve root compression was confirmed by MR Images. Pre-block Visual Analogue Scale(VAS) and ODI scores were taken. Extraforaminal SNRB was given by fellows in spine surgery at our institute in the OT setup under the fluoroscopic guidance. A 23-guage spinal needle was inserted at the junction of pars and transverse process. After feeling the bone at the other end, needle was made to advance few mm laterally (sliding from pars). Contrast dye made from salts of diatrizoic acid was injected. Track of nerve root was visualised and confirmed under c-arm followed by administering 3 cc of 2% xylocaine and 40 mg methylprednisolone acetate through the same needle. Post block VAS score and after 3 weeks ODI score were taken.

Results:

Pre block VAS score of the cases was 7.6 ± 1.4. ODI score was found to significantly change before (68 ± 17) and 3 weeks (37 ± 12) after the procedure. Immediate post-block the visual analogue score decreased to 2 ± 1. There were no reported complications of neural or vascular deficit.

Conclusion:

Selective nerve root blocks (SNRB) have gained a larger aspect of importance for the pain physicians. Transforaminal route of SNRB has been the mainstay till date. But we propose a novel technique of SNRB in the lumbar region as it is safe without any major complications and can be learned/ practised easily.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577bo

Surgical Outcomes
A067: Incidence and Influence of Depression and Anxiety on Clinical Outcome Before and One Year after Spine Surgery for Degenerative Disc Disease

Abstract

Introduction:

It is widely accepted that psychiatric comorbidities have a negative influence on clinical outcome following spine surgery for degenerative disc disease. However, most published data is restricted to postoperative measurements and data from preoperative settings in lacking. We previously demonstrated that mental comorbidities at 3 months follow up are very common and negatively influence clinical outcome. Aim of this study was to assess the incidence and influence of mental comorbidities on clinical outcome one year after surgery.

Methods:

A prospective study of patients undergoing elective spine surgery performed. Evaluation for depression (ADS-K score) and anxiety (STAI-S, STAI-T and ASI-3 scores) were done before and one year after surgery. In addition SF36 physical composite score (PCS), Oswestry Disability Index (ODI), EuroQOL 5D and pain visual analog scale (VAS) were completed preoperatively, 3 and 12 months follow up. Incidence and influence of these psychiatric comorbidities on clinical outcome were examined.

Results:

184 patients met the inclusion criteria. 52.7% were male, mean age was 59.4 years. Abnormal anxiety scores were observed in 59.2%, 36.8% and 40.1% of cases before, at 3 and 12 months follow up, respectively. 25.0% of the patients showed abnormal ADS-K scores preoperatively compared to 10.5% and 14.5% at 3 and 12 months follow up, respectively. However, only 10.6% and 6% of patients developed anxiety and depression only following surgery, respectively. At one year follow up patients with abnormal anxiety scores showed a reduced clinical outcome compared to their counterparts (SF36 PCS: 34.7 vs 41.0, P = .005; EuroQol Index: 0.66 vs 0.82, P = .001; ODI: 30.3 vs 17.8 P = .008). Moreover abnormal ADS-K scores at one-year follow up were also associated with reduced clinical outcome (SF 36 PCS: 33.5 vs 39.7, P = .01; EuroQol Index: 0.55 vs 0.79, P = .001; ODI: 34.3 vs 19.4 P = .008).

Conclusion:

The incidence of depression and anxiety disorders in patients undergoing elective spine surgery is very high. This was also associated with unfavourable outcome one year after surgery. The standard scores for mental health seem highly nonspecific in the preoperative period. Spine specific screening tools are needed.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577bp

A068: AOSpine Needs Assessment at the Spine Surgery Department, University Hospital Basel

Abstract

Introduction:

All planning for the design and development of educational events and resources for the continuing professional development of clinicians should be based on a solid needs assessment process. In the area of spine surgery, many tools have been used to gather information on educational needs and gaps. These include surveys (both online and at events), literature reviews, analysis of hospital data, diaries of questions, and interviews or focus groups, conducted either alone or in combination.

Material and Methods:

AOSpine designed a 4-phase needs assessment process to collaboratively conduct a hospital-based needs assessment at the University Hospital Basel. 1. Identify the participants and the surgeon leaders, 2. Agree a project plan with the team, 3. Gather needs assessment data through online questionnaires, interviews and focus groups, diaries of questions asked in daily practice, and any available statistics from the hospital, and 4. Analyze the data, identify the key findings, and create a plan to address the largest needs and gaps.

Results:

All 21 residents and practicing surgeons who are actively involved in treating spinal pathologies in the department completed the online questionnaire. Nine participated in a follow-up interview and 4 kept a diary of questions over a 1-week period. Analysis of the data created many observations and ideas for delivering education to meet the gaps and perceived needs. For the 12 neurosurgery and orthopedic residents, the 3 highest-rated (weighted average of all responses) pathologies where respondents had a “need for education in the next 2 years” were cervical trauma (4.0), thoracolumbar trauma (3.92), and adult deformity (3.83). For the 9 practicing surgeons, the 3 highest-rated needs were infection (3.00), adult deformity (3.00), and secondary tumors (2.89). In addition to many specific needs being identified for individual pathologies, there was also a high level of interest in surgical approaches and MISS techniques. For 5 specific nontechnical skills, the following gap scores between current and desired level of ability were reported (for residents and practicing surgeons respectively): Use effective communication strategies to gather and share information with patients and their families (0.55, 0.56), Collaborate with other healthcare professionals to implement the treatment plan (0.82, 0.56), Manage your roles as an individual healthcare provider, a member of teams in the hospital or practice, and a leader within healthcare systems (1.18, 1.22), Commit to Lifelong learning, teaching, and mentoring others (1.91, 1.11), and Ensure the best possible outcomes for patients and communities through ethical behavior and adhering to high standards of practice (1.45, 0.67).

Conclusion:

Inviting all surgeons and trainees from the spinal department to participate in this needs assessment resulted in a high level of engagement and a full online response rate. Using mixed methods and analyzing the data in two groups provided an optimal approach to review the information and to identify key findings. Several plans are now being implemented to meet the identified needs.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577bq

A069: Successful Lumbar Surgery Results in Long-Term Improvement in Psychological Well-Being

Abstract

Introduction:

Patients undergoing lumbar surgery often have depressive and anxiety symptoms. Long-term effects of surgery on these psychological symptoms have not been rigorously evaluated. This longitudinal study compared pre- and 2-year postoperative psychological symptoms in 276 lumbar surgery patients and assessed whether change in symptoms was associated with success of surgery.

Material and Methods:

Several days preop patients completed two psychological surveys, the Geriatric Depression Scale (GDS) (possible score 0-30, ≥11 is positive screen for depression) and the Spielberg State Anxiety Inventory (STAI) (possible score 20-80, population norms are used for comparison). Patients also completed the Oswestry Disability Index (ODI) measuring disability from low back pain (possible score 0-100) and a validated Lumbar Surgery Expectations Survey measuring expected improvement for symptoms, function, and mental health (possible score 0-100). Medical comorbidity was obtained according to a standard index. Two years postop patients again completed the GDS, STAI, and ODI from the perspective of their current condition, and pre- to postop changes in score were calculated. Patients also reported new/worse comorbidity since surgery, and amount of improvement obtained for each expectation from which an overall proportion of expectations fulfilled was calculated (range 0 -1, higher = greater fulfillment). Improvement in GDS and STAI was defined as better psychological well-being. Success of surgery was defined as greater proportion of expectations fulfilled and improvement in ODI scores.

Results:

Mean age was 55 years, 56% were men, 78% had chronic spine conditions, 28% had major comorbidity preop, 19% reported new/worse comorbidity postop. Mean GDS scores were 9.8 (preop), 5.1 (postop), and 4.8 (within-patient change, P < .0001). More improvement in GDS scores was associated with a greater proportion of expectations fulfilled (P < .0001) and greater improvement in ODI scores (p<.0001). 41% preop screened positive for depression versus 16% postop (P < .0001). Compared to those who screened positive, those who screened negative postop had a greater proportion of expectations fulfilled (.33 vs .75, P < .0001), and a greater change in ODI scores (13 vs 34, P < .0001). Mean STAI scores were 40 (preop), 31 (postop), and 9 (within-patient change, P < .0001). More improvement in STAI scores was associated with a greater proportion of expectations fulfilled (P < .0001) and greater improvement in ODI scores (P < .0001). 59% preop had anxiety symptoms above population norms versus 26% postop (P = .002). Compared to those who were above population norms, those who were below population norms postop had a greater proportion of expectations fulfilled (.40 vs .79, P < .0001) and a greater change in ODI scores (15 vs 36, P < .0001). All associates persisted when controlled for pre- and postop comorbidity.

Conclusion:

Traditionally, preoperative psychological symptoms have been assessed as predictors of outcomes of lumbar surgery. Our study demonstrated that outcomes of lumbar surgery, in turn, predict postoperative psychological well-being. The strengths of this study are its longitudinal design, use of within-patient change in scores for all measurements, use of patient-centered measurements, and control for pre- and postoperative comorbidity. This study provides evidence that successful lumbar surgery not only improves physical symptoms and function, but also improves psychological well-being.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577br

A070: Habitual Smoking in the Young Employees, Alcohol Intake, Depressive Mood and Non-Sedentary Work Demand have Associations with LBP: A Survey of Employed Workers in a Medical Factory of Japan

Abstract

Introduction:

Understanding of the associated factors with low back pain (LBP) and implementing effective prevention strategies are crucial. If the modifiable associated risk factors (for example, smoking) which develop prevalence and disability due to LBP is uncovered in the working generations, primary care, educational program and so forth could be recommended. Furthermore, potential saving costs for workers’ care system and the society is highly anticipated as well. The purpose of the current cross-sectional survey is to identify a prevalence of present LBP and to analyse modifiable risk factors associated with LBP.

Material and Methods:

A questionnaire could be collected from 1452 out of 1489 workers of a medical factory in November 2015 (collection rate: 97.5%). A self-administration questionnaire was used in the current survey. Age, gender, body height, body weight, and the type of the work demand were also ascertained in the questionnaire, for evaluation of mental condition. The medical component summary score (MCS) from Medical Outcome Study Short-Form 36-Health Survey (SF-36®) was used for evaluation of mental condition. Associations between LBP and age, gender, BMI, smoking, alcohol intake, regular exercise, work demand and mental condition was evaluated by a multiple logistic analysis (P < .05 = significant).

Results:

The mean age of the participants was 38.8 ± 12.8 (mean ± standard deviation). The prevalence of LBP in the present week (pwLBP) was 27.7% (28.1% in men, 26% in women). The odd ratio (OR) for aging was 1.40 (95%CI 1.03 -1.90) in the participants with the age 50 to 59 years referring to age 20 to 29 years. The habitual cigarette smoking (the mean dose: 11.9 ± 6.4 cigarettes/day) has an association with pwLBP in young adults, whose age was 37 years or less, and the OR was 2.07 (95%CI 1.47 -2.93). The alcohol intake (the mean dose: 23.4 ± 37.4g/day) also has a mild association with pwLBP and the OR was 1.33 (95%CI 1.05 -1.68, P < .019). The OR of pwLBP was 1.34 (95%CI 1.02 -1.78, P < .044) in the participants with the light to moderate work demand. The OR in the participants with MCS score less than 35 was 2.64 (95%CI 1.96-3.56).

Conclusion:

Habitual cigarette smoking in the young generation whose age was 37 years or less, alcohol intake, non-sedentary work demand and depressive mood are associated with pwLBP of the employed workers. Therefore, reduction of smoking and alcohol intake, less demand of the non-sedentary work and improvement of depressive mood has a possibility to decrease the present LBP.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577bs

A071: The Relationship between Gastric Esophageal Reflux Disease and Spinal Sagittal Alignment in Elderly Patients

Abstract

Introduction:

It is known that the QOL for aging patients who have spinal kyphosis deformity is frequently impacted by symptoms of gastric esophageal reflux disease (GERD). There is scattered mention in case study literature where refractory GERD has been seen to improve rapidly after correction of sagittal deformity. The purpose of this study was to evaluate the relationship between gastric esophageal reflux disease and spinal sagittal alignment.

Material and Methods:

888 consecutive patients seen at our osteoporosis outpatient clinic between 2009.9 and 2015.7 were asked to complete frequency scale for the symptoms of GERD (FSSG) and Questionnaire for the Diagnosis of Reflux Disease (QUEST) questionnaires. After excluding scoliosis patients, 726 patients (111 males, 615 females) remained who had completed both questionnaires and for whom whole spine radiographs were available. Patients who scored positively on both questionnaires (8 or more on the FSSG and 4 or more on the QUEST) were assigned to the GERD group. On the other hand, non-GERD group was determined as a negative of both questionnaires. Spinal sagittal alignment was evaluated using measurements of thoracic kyphosis (TK: T2-T12), low thoracic kyphosis (T5-12), thoracolumbar sagittal angle (T10-L2), lumber lordosis (LL: T12-S), pelvic tilt (PT), sacral slop (SS), pelvic incidence (PI), and sagittal vertical axis (SVA). From DEXA scan data we calculated total bone mass density from L2-5, and used multiple regression analysis to compare each of the sagittal parameters between the GERD and non-GERD groups.

Results:

98 of 726 patients (13.5%) (10 males, 88 females) were included in the GERD group. Non GERD group was 446 patients (66 males, 380 females). Averages were 41.7°/41.5°TK, 34.6°/33.8°T5-12, 21.9°/16.2°at T10-L2, 36.4°/34.5°at T12-S, 28.6°/27.0° SS, 28.5°/26.4° PT, 53.6°/48.3° PI and 52.6mm/45.6 mm SVA for the GERD group and Non-GERD groups respectively. Significant correlation to GERD was found only for TK at T10-L2 and PI (P < .001). Mean BMD (g/cm2) was 0.701/0.736 at L2-5.

Conclusion:

The diagnostic reliability of the FSSG and QUEST questionnaires individually is reported to be about 60% so studies with endoscopic findings are planned. However, with the combined use of both questionnaires as criteria for this study’s GERD group, reliability is thought to be high. We detected the level of sagittal alignment related GERD. Since the vertebra at the thoracolumbar junction are at high risk for fractures, early detection and treatment of osteoporosis is also important in the prevention of GERD.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577bt

A072: Cross-cultural Adaptation and Validation of the Turkish Version of the Core Outcome Measures Index for Low Back Pain

Abstract

Introduction:

Patient based outcome measures have been recommended for evaluation of patients with spinal disorders and outcome of treatments. Several measurement tools are available in different languages, encouraging multinational studies and the use of international spine registry systems. The Core Outcome Measure Index (COMI) is a self-administered multidimensional questionnaire intended to evaluate the affect of LBP on daily life. It has six core questions about pain (back and leg), function, symptom-specific well-being, quality of life, work and social disability. It is the recommended outcome instrument in the Spine Society of Europe Spine Tango Registry. The aim of this study was to produce a cross-culturally adapted and validated Turkish version of the COMI Back questionnaire.

Material and Methods:

A cross-cultural adaptation of the COMI into Turkish was carried out using established guidelines. Ninety-six Turkish-speaking patients with non-specific LBP were recruited from orthopedic and physical therapy outpatient clinics in a public hospital. They completed a booklet of questionnaires containing Turkish version of COMI, adjectival pain scale, Roland Morris disability questionnaire (RM), European 5 Dimension Questionnaire (EQ-5D) and brief version of World Health Organization Quality of Life Questionnaire (WHOQOL- BREF). Within following 7-14 days, 67 patients, reported no or minimal changes in their back pain status, completed the Turkish COMI again to assess reproducibility.

Results:

Data quality was good with very few missing answers. COMI summary index score displayed %3 floor effects and no ceiling effects. The correlations between the COMI summary index score and the each of the full instrument whole scores were found to be excellent to very good (Rho = −0.81−0.74). Reliability expressed as intraclass correlation coefficient (ICC) was 0.95 (95% CI 0.91-0.97. Standard error of measurement (SEMagreement) was acceptable 0.41 and the minimum detectable change (MDC95%) was 1.14.

Conclusion:

Turkish version of the COMI has acceptable psychometric properties. It is a valid and reliable instrument and cross culturally adapted, in accordance with established guidelines, for the use by Turkish speaking patients. It can be recommended for use in evaluation of patients with chronic LBP in daily practice, in international multicenter studies and in spine registry systems.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577bu

Lumbar Spondylolisthesis
A073: Decompression Versus Fusion for Grade I Degenerative Spondylolisthesis: A Meta-Analysis

Abstract

Introduction:

Degenerative spondylolisthesis (DS) remains one of the most common indications for spine surgery. Although large multi-institutional trials supported surgical treatment for this pathology, and recent meta-analysis has compared different fusion techniques, the best surgical management option for patients with only grade 1 disease has not been determined. Therefore, the purpose of this study is to compare decompression and fusion with decompression alone for the treatment of grade 1 degenerative spondylolisthesis.

Material and Methods:

Following PRISMA guidelines, the MEDLINE, Embase, and Ovid electronic databases were systematically reviewed to assess for studies evaluating patients with grade 1 spondylolisthesis published from January 1996 until July 2016. Within these studies, we stratified all patients into two cohorts; the first group had patients who underwent a decompressive-type surgery and the second cohort consisted of patients who also underwent a fusion procedure. We specifically looked at clinical outcomes, complications, reoperations, and additional surgical details such as blood loss. Descriptive statistics were used to describe both cohorts; then, random effect models were used to determine the rates of the specified outcome metrics, with its 95% confidence intervals.

Results:

A total of 17 studies met our criteria. There were 9 studies (N = 591 patients) who were part of the decompression cohort, with a mean age of 67 years (range, 62-69 years), a mean BMI of 24 kg/m2 (range, 23-26 kg/m2), and 54% were women. The fusion cohort had 14 studies (N = 434 patients) with a mean age mean 60 years (range, 49-70), had a mean BMI of 24 kg/m2 (range 23-26 kg/m2) and 71% were female). In both cohorts, the pain (leg and low back) significantly decreased, the physical component of the Short Form 36 (SF-36), and overall increased the outcome metric scales. In terms of complications, the decompression cohort had a 7.5% complication rate (95% CI of 2 to 16%) and the fusion had a 9.2% complication rate (95% CI of 7 to 12). In contrast, the reoperation rate was higher in the decompression cohort with a 6% rate (95% CI of 1 to 15%) than in the fusion cohort with a 4.4% rate (95% CI of 2 to 7).

Conclusion:

With the current literature, it does not appear to be any advantage of one procedure over the other. Patients undergoing decompression alone tended to be older and had a higher percentage of leg pain while fusion patients tended to be younger and have more low back pain. The decompression cohort had fewer complications but a higher revision rate. Future studies specifically assessing patients with low grade DS are needed to determine the benefits and cost effectiveness of one procedure versus another.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577bv

A074: Re-admission, Re-operation, and Patient Reported Outcomes after Lumbar Fusion Surgery for Spondylolisthesis in 480 Patients from the QOD Registry

Abstract

Introduction:

The American Association of Neurological Surgeons launched the National Neurosurgery Quality and Outcomes Database (QOD), a prospective longitudinal registry utilizing patient reported outcome instruments and includes data to measure the safety and quality of spinal surgery. In the present study, the authors analyzed 12-month outcomes data for patients undergoing lumbar fusion surgery for grade 1 degenerative spondylolisthesis.

Material and Methods:

The prospective QOD dataset from top enrolling sites was retrospectively queried and we found 480 patients undergoing elective spine surgery for one, two, or three level degenerative grade 1 lumbar spondylolisthesis. Baseline, 3-month, and 12-month follow-up readmission rates, re-operation rates, and patient reported outcomes [Oswestry Disability Index (ODI) and back and leg pain Numeric Rating Scale (NRS)] were collected. The absolute differences between 12-month post-operative and baseline ODI and back and leg pain NRS scores were evaluated.

Results:

The 30-day readmission rate was 3.3%. The 90-day readmission rate was 4.6%. The 30-day re-operation rate was 3.1%. The baseline ODI scores differed from the 12-month scores by an absolute difference of 12.1 ± 8.8 (P < .001). The baseline back and leg-pain NRS scores differed from the 12-month scores by an absolute difference of 3.9 ± 3.1 and 4.0 ± 3.6, respectively (P < .001).

Conclusion:

This prospectively collected data is uniquely generated through the spine surgeon’s office directly from the patients. Lumbar fusion surgery for grade 1 degenerative lumbar spondylolisthesis is associated with low 30-day re-operation rates and 30- and 90-day readmission rates. Fusion surgery was associated with significant improvements in patient-reported outcomes at one-year follow up.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577bw

A075: The Effect of Surgical Wait Time On Patients With Degenerative Lumbar Spondylolisthesis: A Canadian Spine Outcomes and Research Network (CSORN) Study

Abstract

Introduction:

Study Design: Ambispective review of the Canadian Spine Outcomes and Research Network (CSORN) registry cohort.

Objective:

To investigate the effect of surgical wait time (SWT) on the baseline and postoperative patient reported outcome (PRO) metrics in surgical patients with degenerative spondylolisthesis (DS), and to identify independent predictors of outcome in surgical patients with DS.

Summary of Background Data:

DS is the most common form of lumbar spondylolisthesis. Surgery is considered with failure of non-operative management and persisting symptoms. From a patient perspective, rapid access to spine specialist care is preferred. However SWT to initial spine specialist consult and elective surgery can be prolonged, especially in a single-payer health care system.

Material and Methods:

Surgical DS patients treated between 2013 and 2015 were identified in the CSORN registry. SWT was defined as the period from surgical wait listing to day of surgery, with study population dichotomy to: (1) SWT < 3-months; and (2) SWT ≥ 3-months. Baseline and post-operative (3-month, 1-year) demographic and PRO metrics were analyzed using bivariate and multivariate modeling.

Results:

At baseline, the SWT < 3-months cohort had 158 patients while the SWT ≥ 3-months cohort had 146 patients. Both SWT groups had similar distributions of age, gender, symptom duration, and smokers. The SWT < 3-months cohort however had more compensated patients (P < .01). Both groups were also similar in terms of baseline PROs and spine specific metrics except for the SWT ≥ 3-months cohort who were more depressed (P < .01). At 3-months, the SWT ≥ 3-months cohort showed greater satisfaction (96.2% vs. 86.2%, P < .01). This effect was not maintained at 1-year. All other PRO metrics were similar at 3-months and 1-year. Multivariate modeling showed that both surgical wait times and symptom duration were not independent predictors of outcome in surgical DS patients. Subgroup analysis of symptom duration showed indifference in outcomes at 3 months but superior results at 1 year for those with shorter duration of symptoms.

Conclusion:

Prolonged surgical wait time was not detrimental on the post-operative outcome in surgical patients with degenerative spondylolisthesis. Subgroup analysis however showed better results in patients with shorter duration of symptoms.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577bx

A076: Surgical Outcome of Pedicle Screw-Lamina Hook Plus Isthmic Bone Grafting through Wiltse Approach for Lumbar Spondylolysis in Children and Adolescent: An Over 5 Years Follow-up

Abstract

Introduction:

To investigate the long-term effect of pedicle screw-lamina hook plus isthmic bone grafting through Wiltse approach for lumbar spondylolysis in children and adolescent.

Material and Methods:

From July 2005 to May 2009, 43 patients (31 males, 12 females; 9-25 years old, average 17.2) with lumbar spondylolysis combined with or without slippage were enrolled in our study. All of the patients were treated with the pedicle screw-lamina hook plus isthmic bone grafting and followed up at least for 5 years. There were 33 Single level spondylolysis and 10 double level spondylolysis. The symptom status were evaluated by Visual analogue scale (VAS) score and Oswesty dysfunction index (ODI) preoperatively and at 3days, 3 months, 6 months, 1 year after surgery and the final follow-up. The surgical outcome was assessed by Henderson method. AP view, flexion and extension view, oblique X-rays were performed at every time point. 3D-CT scan was taken 1 year after surgery to assess the bone fusion. Modified Pfirrmann grade was used to evaluate the disc degeneration. And the adjacent segmental degeneration was assessed by the UCLA grade on the X-ray of the final follow-up.

Results:

All patients were follow-up over 5 years (68-122 months, average 83.3). The surgery was successful, the average operation time was 125 min (85-155 min), the average intraoperative blood loss was 120 ml (80-160m1), and the post-operative drainage was 54m1 (35-85m1). No complication was observed. The VAS and ODI score of postoperative was significantly different from that pre- operation (P < .05). The bone fusion was observed in 39 patients after 1-year follow-up, the fusion rate was 90.7%. There was no detachmented the pedicle screw-lamina hook and intervertebral altitude loss. UCLA grade showed no adjacent segmental degeneration occurred. 8 cases had degeneration of lumbar intervertebral disc on the MRI images at the final follow-up.

Conclusion:

Compared with the multi-segmental fixation and interbody fusion, the pedicle screw-lamina hook plus isthmic bone grafting is a single-fixation, and this operation is technically simple and no sacrifices of lumbar motion ranges, and it is proved to be effective.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577by

Novel Technologies and Sacral Joint Fusion
A077: Twelve-Month Outcomes from a Multicenter Randomized Controlled Trial of Minimally Invasive Sacroiliac Joint Fusion with Triangular Titanium Implants vs Conservative Management

Abstract

Introduction:

The sacroiliac joint (SIJ) is a common cause of chronic, unremitting Lower Back Pain (LBP). A significant number of patients do not respond to Conservative Management (CM). New Minimal Invasive SIJ fusion procedures were developed.

Material and Methods:

103 Adults with chronic SIJ pain at 9 sites in 4 European countries were randomly assigned to either minimally invasive SIJF using triangular titanium implants (N = 52) or CM (N = 51). CM was performed according to the European guidelines for the diagnosis and management of pelvic girdle pain and consisted of optimization of medical therapy, individualized physical therapy (PT) and adequate information and reassurance as part of a multifactorial treatment. Subjects assigned to CM not benefitting from it for at least 6 months, were allowed cross over to any other treatment, including minimally invasive SIJF. Endpoints included low back pain and leg pain scores, quality of life using EQ-5D-3 L, disability using ODI, SIJ function using ASLR, mental state using Zung depression scale and adverse events.

Results:

Results. At 6 months, the improvements in LBP and ODI were higher in the SIJF group vs. CM group (both P < .0001) and well exceeding the Minimal Clinical Important Difference (MCID). ASLR, EQ-5D-3 L, Zung depression scale, walking distance and satisfaction were statistically superior in the SIJF group. The frequency of adverse events did not differ between groups. One case of postoperative nerve impingement occurred in the surgical group. In the surgical group, the 12-month improvements in pain, disability and quality of life were similar to those seen at 6 months. 37 (76%) of the subjects assigned to CM and still participating at 6 months had a change of ≤20 in LBP VAS, 21 (43%) of them crossed over to SIJ fusion. Amongst crossovers, changes in pain, ODI and QOL at 6 months after crossover were similar to those in the group initially assigned to surgical care.

Conclusion:

This study demonstrates that in patients with chronic SIJ pain, minimally invasive SIJF using triangular titanium implants was safe and more effective than CM in relieving pain, reducing disability, improving function, and improving quality of life. The response to minimally invasive SIJF was maintained at 12months. The majority of subjects assigned to conservative management did not benefit (change in LBP VAS ≤20) from it for at least 6 months.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577bz

A078: Is Kambin’s Triangle Safe for Lumbar Interbody Fusion? Minimally Invasive Extraforaminal Lumbar Interbody Fusion (ELIF)

Abstract

Introduction:

We introduce a minimally invasive extraforaminal lumbar interbody fusion (ELIF) that is the novel lumbar approach, a newly emerging minimally invasive technique for treating degenerative lumbar disorders.

Materials and Methods:

23 patients who received minimally invasive ELIF through the Kambin’s triangle included in this study, retrospectively. ELIF performed through the Kambin’s triangle. We checked the radiologic result as following: 1) implant related complications, and 2) fusion status. Clinical result checked as following: 1) Surgery related neurologic complications 2) Visual Analogue Scale (VAS) and 2) Oswestry Disability Index (ODI).

Results:

The mean age was 58.96 years and the mean follow-up period was 29.96 months. According to the result, implant related complications were 4 cases (17.39%) and fusion failures were 5 cases (21.74%). We experienced 5 cases (21.74%) of surgery related neurologic complications and all patient’s neurologic complications recovered within 1 month after operation. The mean VAS (Back) prior to surgery was changed as following: Preoperative: 6.43, and 2 years after operation: 3.04. The mean VAS (Leg): Preoperative: 7.70 and 2 years after operation: 2.91. The mean ODI score: Preoperative: 76.78 and 2 years after operation: 29.91.

Conclusion:

According to the result, we obtained excellent clinical results using the minimally invasive ELIF without any serious traversing or exiting nerve injury. But, fusion rate and cage subsidence remained still overcome issue. If we developing this novel surgical technique, we will obtain the excellent clinical result using the minimally invasive percutaneous procedures.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577ca

A079: A Patient-Specific Image-Based Computational Model for Biomechanical Evaluation and Design of 3D Printed Polycarbonate Fusion Cages

Abstract

Introduction:

Spinal fusion surgery is accepted as the gold standard for the treatment of degenerative disc diseases when a conservative approach fails. The most commonly used devices for this procedure are interbody cages made of metals such as titanium, tantalum or polymers as polyether ether ketone. The mismatch in mechanical properties between the implant and surrounding bone has been largely suggested as a cause of implant subsidence and therefore suboptimal outcomes. While it is largely recognized that the geometry of the interbody cage is crucial in restoring the load patterns, the optimal implant design still remains debatable. Standard implants and instrumentations may be unsuitable for some surgical cases. Hence, patient-specific designs can potentially improve clinical outcome in spinal surgery by creating an optimal match for each anatomy. Recent advances in computational models combined with additive manufacturing technology can be now used to optimize existing device and develop novel implant designs with control over the architecture, which may facilitate cell adhesion and bone in-growth.1,2 Moreover, 3D printable biomaterials such polycarbonate have recently shown feasibility to spinal cages that provide appropriate mechanical properties to withstand the physiological loading configuration and support the process of osteointegration2-4. This study aims to use a particular computational technique such as finite element analyses (FEA) to optimise existing device and design more effective solutions for spinal fusion implants.

Material and Methods:

Standard FEA were set up to simulate different loading conditions such as compression, flexion, extension and bending on a conventional cage design. Furthermore, a novel cage was designed to match the pre-operative vertebrae derived from computed tomography (CT) images of a patient. Two materials were modelled: titanium and polycarbonate. Titanium was used as control materials during the computational analysis, due to its wide applications in spinal implants. Polycarbonate was included as widely available within additive manufacturing techniques. The influence on the performance of four different filling densities (25%,50%,75%,100%) of 3D printed polycarbonate was studied through mechanical testing. Micro computed tomography (CT) was used to assess structural reproducibility and generate 3D models of the additive manufactured polycarbonate porous structures. For each of the cages, all four filling densities were simulated through a patient-specific two-level model of the spine within a physiological load distribution.

Results:

Computational results in terms of stress results showed different mechanical responses when using different materials for the spinal cage, manufacturing technique, cage architecture and filling density. In particular, stresses increased with reducing material density. In addition, stress peak values were lower than the respective risk of failure in all the simulated cases, confirming the feasibility of polycarbonate implants. The patient-specific design showed an even stress distribution consistently within anatomical constraints.

Conclusion:

The process suggested the feasibility of a lighter, affordable and patient-specific interbody cage for spinal fusion. Computational analyses may be utilized to balance the complex requirements of load transfer and porosity to avoid stress-shielding effects and support implant osteointegration.

References

1. Capelli C, Serra T, Kalaskar D and Leong J. Computational models for characterisation and design of patient-specific spinal implant. The Spine Journal. 2016; 16: S53-S4.

2. Serra T, Capelli C, Kalaskar D and Leong J. Feasibility of manufacturing a patient-specific spinal implant. The Spine Journal. 2016; 16: S64-S5.

3. Figueroa-Cavazos JO, Flores-Villalba E, Diaz-Elizondo J, et al. Design Concepts of Polycarbonate-Based Intervertebral Lumbar Cages: Finite Element Analysis and Compression Testing. Applied Bionics and Biomechanics. 2016; 2016: 9.

4. Serra T, Capelli C, Toumpaniari R, et al. Design and fabrication of 3D-printed anatomically shaped lumbar cage for intervertebral disc (IVD) degeneration treatment. Biofabrication. 2016; 8: 035001.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577cb

A080: Minimally Invasive Sacroiliac Joint Fusion Using Triangular Titanium Implants: Pooled Analysis of 3 Prospective Clinical Trials

Abstract

Introduction:

The sacroiliac joint (SIJ) is a contributing factor in 15-30% of patients evaluated for chronic low back pain. A variety of non-surgical treatments are commonly provided for SIJ pain, including physical therapy, SIJ steroid injections and radiofrequency neurotomy. So far, no high-quality evidence supports long-term pain relief from any of these treatments. Over recent years, minimally invasive SIJ fusion (SIJF) has been introduced as a potential treatment alternative. Despite a large number of commercially available devices, very little outcome evidence exists for devices other than triangular titanium implants (TTI). There are three currently ongoing prospective trials on TTI and their preliminary results have shown concordant improvements in pain, disability and quality of life after SIJF. Two of these trials are randomized controlled trials comparing SIJF to conservative management (CM). Herein we pool the current data of the three relevant prospective trials to examine treatment outcome after SIJF using TTI.

Material and Methods:

The trials included in this pooled analysis are the Investigation of Sacroiliac Fusion Treatment (INSITE) trial, the iFuse Implant System Minimally Invasive Arthrodesis (iMIA) trial and the Sacroiliac Joint Fusion With iFuse Implant System (INSITE) trial. Data from these trials were combined on an individual patient basis and analyzed using mixed modeling taking into account expected variation of patient characteristics and outcomes across sites. Pain was quantified using the visual analogue scale (VAS, range 0-100), disability was assessed using the Oswestry disability index (ODI) and the quality of life was described using the EuroQuol score (EQ-5D-3 L).

Results:

We included 423 subjects from two geographies (US and Europe). Mean age was 50 years and 70.4% of subjects were women. Mean duration of pain prior to enrollment was >5 years. SIJ pain averaged 80 VAS points at baseline. In the SIJF group, pain levels dropped by 48 VAS points (44-52) at 12 months and 52 VAS points (47-56) at 24 months. Mean reductions in ODI in the SIJF group were 26 (22-29) and 26 (22-30) points at 12 and 24 months, respectively. In the CM groups, changes in pain and ODI scores were minimal. Effect sizes (i.e., the differential in improvement in scores observed with surgery as opposed to CM) were 37.8 points (95% CI 32.4-43.2) for VAS, 18.4 points (95% CI 14.3-22.4) for ODI, and 0.24 points (95% CI 0.17-0.30) for EQ-5D-3 L. Wound-related complications (eg, infection) occurred in 2.1% (95% CI 0.3-4.4%). The early surgical revision rate was 1.2% (0.4-2.5%) and the late revision rate was 1.6% (0.1-5.1%).

Conclusion:

This pooled analysis provides evidence that in patients with pain originating from the SIJ, SIJF using TTI may lead to early and sustained improvements not only in SIJ pain but also in disability and quality of life. Treatment effect sizes were comparable to those known from prospective trials of other commonly performed spine surgeries. The rates of procedure-related wound problems and early revisions were low and consistent with the minimally invasive nature of the procedure.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577cc

Endoscopic and Minimally Invasive Spine Surgery
A081: The Safety Profile of Percutaneous Minimally Invasive Sacroiliac Joint Fusion: A Systematic Review and Meta-Analysis

Abstract

Introduction:

Sacroiliac joint (SIJ) fusion is gaining popularity amongst spine surgeons for treatment of SIJ dysfunction. SIJ fusion can be accomplished by open or minimally invasive (MI) surgery. The MI technique has increased in popularity as it is believed to be associated with minimal blood loss, less surgery time, and decreased length of hospital stay. This is a systematic review of the existing literature to determine the safety of MI SIJ fusion through the determination of the rate of procedural and device related intraoperative and postoperative complications.

Material and Methods:

A systematic review was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. PubMed and Scopus were searched using the terms “sacroiliac joint AND fusion”. All original English language retrospective and prospective studies of at least five patients with reported adverse event or complication rates for MI SIJ fusion were included for analysis. Complications were defined as procedural if reported as most likely or definitely due to the MI surgery and device related if secondary to the implant device. Random effects meta-analysis was performed for pre-operative and post-operative Visual Analog Score (VAS) pain ratings and Oswestry Disability Index (ODI) to quantify the efficacy of MI fusion in studies providing both mean scores and standard deviations (SD). Post-operative VAS and ODI scores were from last recorded follow-up.

Results:

Fourteen studies met our inclusion criteria. Seven studies reported VAS scores while five studies provided ODI values. Twelve of the studies investigated triangular porous titanium plasma spray coated implants while two studies used hollow modular anchorage screws packed with demineralized bone matrix. A total of 720 patients (499F/221 M) with a mean follow-up of 22 months were included in the analysis. 99 patients (13.75%) underwent bilateral SIJ arthrodesis resulting in a total of 819 SI joints fused. There were 90 documented procedural-related complications (10.99%) with the most common adverse events being surgical wound infection/drainage (n = 13), trochanteric bursitis (n = 11), and hematoma formation (n = 9). 25 adverse events were attributed to be directly caused by the implant device (3.05%) with nerve root impingement (n = 13) being the most common. The rate of revision was found to be 2.56%. The association between the type of implant and device related complications was not statistically significant (P = .955). MI SIJ fusion reduced VAS pain scores from 82.42 (95% CI 79.34-85.51) to 29.03 (95% CI 25.05-33.01) and ODI scores from 57.44 (95% CI 54.73-60.14) to 29.42 (95% CI 20.62-38.21). Patient satisfaction with outcomes was high at 93.14%, with 86.01% stating they would have the same surgery again.

Conclusion:

MI SIJ fusion reduces pain and improves functionality of accurately diagnosed SIJ dysfunction. Possible risks and complications of the procedure, including those requiring revision, are not uncommon; however patient satisfaction is high. Additional studies are needed to further enhance the safety of the procedure.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577cd

A082: Does the Addition of Either a Lateral or Posterior Interbody Device to Posterior Instrumented Lumbar Fusion Decrease Cost Over a 6 Year Period?

Abstract

Introduction:

The economic burden of spine-related health care in the United States has been estimated at $100 billion dollars annually and a 65% increase in spine-related health care medical expenditures from 1997 to 2005 was reported. This emphasizes the importance of economic evaluation of surgical procedures. With an increasing system-wide focus on value-based health care, the goal of economic evaluation is to identify high quality of care which minimizes costs. Few studies have compared the costs of different approaches for lumbar fusion surgery. The purpose of this study was to compare the costs of single-level lumbar fusion, performed as (1) posterior instrumented fusion alone (PSF), (2) posterior interbody fusion with posterior instrumentation (PLIF), or (3) minimally invasive lateral interbody fusion with posterior instrumentation (MILIF), over a period of 6 years.

Materials and Methods:

Patient charts were retrospectively reviewed for demographic and surgical details. Patients were followed up with a telephone questionnaire to obtain information on reoperation status and satisfaction. In order to perform cost estimation from the payer’s perspective, the average surgery-related Medicare reimbursement was calculated for the three treatment groups, for index procedures (PSF-$34,432, PLIF-$36,605, MILIF-$52,879) and reoperations (PSF-$35,098, PLIF-$29,292, MILIF-$43,870) as cost estimates. Using rates published previously, the mean cost for epidural injections per patient was estimated ($2,864). Survival analysis (Kaplan-Meier and multivariate Cox regression analysis) was performed to assess the time to elevated resource use (defined as greater than 90% of patients in this study or $68,672). Multivariate analysis was performed to assess overall satisfaction.

Results:

A total of 337 patients, 45, 222 and 70 in the PSF, PLIF and MILIF groups respectively, were included. Overall follow-up rate was 63% at 6 years. PSF patients were significantly older (PSF-72 ± 12 vs PLIF-59 ± 13 vs MILIF-65 ± 10 years, P < .001). Surgical time was lowest in the PSF group (P < .001), while blood loss was lowest in the MILIF group (P < .001) at index procedure. The length of stay after the index procedure was not significantly different among groups (P = .369). Kaplan-Meier analysis showed that PLIF patients were less likely to reach the cut-off compared to PSF (P = .002) and MILIF (P = .006) at an average follow-up of 6 years. Multivariate Cox regression analysis showed that PSF patients and MILIF patients were 3.3 and 3.4 times more likely to reach the elevated resource use cut-off (PSF-HR 3.280, P = .017, MILIF-HR 3.370, P = .017). Multivariate logistic regression showed that MILIF patients were 3.3 times more likely to be satisfied compared to PLIF patients (OR 3.320, P = .002).

Conclusion:

Multivariate Cox regression analysis showed that patients undergoing MILIF or PSF were more likely to have higher resource utilization than those undergoing PLIF and thus incur greater costs to payers at an average follow-up of 6 years. The high cost estimate for procedures in the MILIF group and for reoperations for PSF patients led to greater costs compared to the PLIF group. Multivariate logistic regression demonstrated that patients in the MILIF group were more likely to be satisfied with the overall result of their surgery, compared to PLIF patients.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577ce

A083: Contralateral Keyhole Endoscopic Surgery (CKES) for Lumbar Spinal Stenosis and Lumbar Disc Herniation: Technical Note and Preliminary Results

Abstract

Introduction:

The purpose of this study was to determine the feasibility and efficacy of contralateral keyhole endoscopic surgery (CKES) for treating lumbar spinal stenosis and lumbar disc herniation.

Material and Methods:

We performed percutaneous endoscopic sublaminiar decompression via the contralateral interlaminar approach in 95 patients with central canal stenosis or lateral recess stenosis and/or herniated disc. All procedures were performed under epidural anesthesia. Firstly, the epidural space was accessed under fluoroscopic guidance; the only tip portion of the handmade working sheath was located within the epidural space to prevent nerve compression injury by an instrument. And then we were partially removed the base of spinous process, the caudal edge of the upper lamina and the rostral edge of the lower lamina to make a keyhole using a 3.5-mm drill bit and punch, thereby allowing surgeon to more easily handle endoscope. After the drilling, the contralateral ligamentum flavum was removed by using punch. The lateral recess and the traversing nerve root were completely decompressed. Additionally, we performed selective fragmentectomy in patients with herniated discs. The mean age was 59.2 years and there were 47 men and 48 women. The mean follow-up period was 6.8 months. Clinical results were evaluated using Visual Analog Scale (VAS) and modified MacNab criteria.

Results:

The symptom was relieved immediately after the surgery. The mean operating time was 68.2 minutes. The VAS score improved significantly from 6.8 points preoperatively to 2.3 points after the surgery. 79 (83.1%) had a good or excellent result according to the MacNab criteria. Complications included two cases of epidural hematoma, three cases of transient dysesthesia and three cases of dura tear.

Conclusion:

CKES is a safe and effective minimally invasive surgical technique that extends the percutaneous endoscopic lumbar discectomy indications for lumbar disc herniation and is a novel and useful procedure in treating lumbar spinal stenosis

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577cf

A084: Radiological Status of Paravertebral Muscles after Bi-portal Arthroscopic Spinal Surgery (BASS)

Abstract

Introduction:

Surgery involving a microscope or uniportal endoscope is now one of the most common types of minimally invasive spine surgeries performed worldwide. However, the procedure still has drawbacks related to its narrow view, steep learning curve, and technical problems. Recently, many preliminary or technical reports regarding biportal arthroscopic spinal surgery (BASS) have been published and have demonstrated that BASS can resolve these drawbacks. However, it would useful to determine the degree of paravertebral muscle injury after BASS using two portals and saline irrigation during the entire procedure. Therefore, we examined the radiological status of the paravertebral muscles after BASS.

Material and Methods:

A total of 48 patients were reexamined by magnetic resonance imaging (MRI) due to the recurrence of neurological symptoms during the follow-up period after BASS using a unilateral inter-laminar approach between September 2015 and March 2016. Of these, 30 patients diagnosed with lumbar spinal stenosis or lumbar disc herniation were included in this retrospective study. Patients with more than the two lesions required for surgery, previous lumbar surgery, spinal infections, or who underwent BASS via a trans-foraminal approach were excluded. We assessed the radiologic status of the paravertebral muscles by grading the extension of paravertebral muscle high signal intensity on T2-weighted MR images (0: normal, 1: partial, 2: total). The MR images were checked and graded on three occasions: preoperatively (aMRI_1), at 1 day after surgery (aMRI_2), and at the time the MRI was re-taken due to the recurrence of neurological symptoms (aMRI_3). The third MRI was taken on the 26th day (range, 1–122 days), on average, after BASS, and then this day was sequentially subdivided into three groups (A: less than 2 weeks, B: 2–4 weeks, C: more than 4 weeks). Then we attempted to determine the critical period when the radiological muscle status was normalized. We also examined the operation time to assess its correlation with muscle status.

Results:

In the aMRI_1, all cases were graded 0. In the aMRI_2, no cases were graded 0, 29 were 1, and 1 was 2. In the aMRI_3, 12 cases were graded 0, 16 were 1, and 2 were 2. No significant differences were identified among the three groups in terms of age, sex, operation level, operation time, aMRI_1, and aMRI_2. However, in aMRI_3, a significant difference was found among the groups (P = .002, Kruskal-Wallis H test), and in the C group, in particular, the grade was significantly low (P = .006, Dunn multiple comparisons test). The average operation time was 111.3 ± 40.0 min (range, 45–210 min) and it was not significantly correlated aMRI_2 or aMRI_3. However, there was a significant negative correlation between the time when the MRI was re-taken and aMRI_3 (P = .0053, rho = −0.495, Spearman correlation test).

Conclusion:

Paravertebral muscle injury after BASS was localized to a limited area and spontaneously normalized.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577cg

Basic Science Spinal Cord Injury
A085: Deleterious Effect of Methylprednisolone on Spinal Cord After Acute Traumatic Injury: Down-regulation of Acuaporine-4 Expression and Persistence of Blood-Spinal Cord Barrier Disruption

Abstract

Introduction:

After spinal cord injury (SCI), primary damage starts with the contusion and hemorrhage and continues with an inflammatory process with glia reactivity, apoptosis, blood-spinal cord barrier (BSCB) disruption and consequently vasogenic edema. Spinal cord edema is a major clinical problem since this structure is contained by the dura and the spinal canal. Swelling leads to nervous tissue compression and ultimately to ischemia and cell death in the next few hours after trauma. The use of corticosteroids following acute SCI is a controversial practice, since the administration of high doses of methylprednisolone (MP) is justified by the work conducted by Bracken MB in the past 2 decades with the National Acute Spinal Cord Injury Studies (NASCIS I, II and III trials). However, the methodological quality of the NASCIS work has been extensively criticized. A new Clinical Practice Guideline recently published for the management of spinal cord trauma advises against the use of MP following SCI, highlighting that the indication has not been approved by the Food and Drug Administration and that currently there is no evidence of level I or II regarding its clinical benefit. Contrariwise, secondary effects have been extensively documented. Since this malpractice continues around the world, particularly in low-income countries, it is important to determine whether MP confers any beneficial effect that justifies its use in acute SCI. For this, we used an acute experimental model of SCI in rats administered with MP and determined the effects on spinal cord edema and the expression of acuaporine-4 (AQP4), a water channel involved in edema formation and resolution.

Material and Methods:

A total of 24 adult Long-Evans rats weighing 250-400 g were anesthetized with pentobarbital intraperitoneally (i.p.) (50mg/Kg). Rats were subjected to a severe spinal cord contusion at T9, which was generated using an impactor system. Rats treated with MP received an i.p. injection of 30 mg/Kg and an equivalent volume of isotonic saline solution was administered to control animals. Twenty-four h after SCI rats were killed and tissues were fixed and collected to analyze AQP4 expression by immunofluorescence and confocal microscopy, in a separate group of rats, an i.v. bolus of Evans blue was administered 30 min before killing the animals and fresh tissues were collected to assess BSCB integrity.

Results:

Spinal cord contusion parameters and neurological deficits generated after SCI were very consistent across groups. We observed a clear loss of AQP4 expression in astrocyte processes in the groups treated with MP, regardless of SCI. Spinal contusion seemed not to affect AQP4 expression. Consistently, we found more extravasation of Evans blue in the SCI group treated with MP, suggesting that loss of AQP4 resulted in a diminished capacity for edema resolution.

Conclusion:

Our results are consistent with the deleterious effect evidenced clinically when SCI patients are treated with MP during the first 24 h, since MP seems to worsen spinal cord edema due to AQP4 down-regulation and persistence of BSCD disruption in injured rats.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577ch

A086: Biomechanical Evaluation of Fusion and Non-Fusion Spinal Instrumentation used in Scoliotic Patients

Abstract

Introduction:

Scoliosis is a three-dimensional deformity of the spine and trunk that affects individuals of all ages. Fusion spinal instrumentation is implemented for individuals with mature spines, while non-fusion spinal instrumentation is implemented for individuals with growing spines. Biomechanical testing of fusion instrumentation is commonly performed using ASTM F1717 standardized testing, but the effects of wedding-band connectors for non-fusion instrumentation has not been evaluated. Patients with a growing spine have fewer pedicle screws to share the load with the spine; therefore, there is a desire for non-fusion instrumentation to withstand greater loads across the instrumentation. The purpose of this study was to characterize the mechanical performance of fusion versus non-fusion instrumentation using ASTM F1717 methodology.

Material and Methods:

A uniaxial load frame was used to biomechanically test fusion and non-fusion spinal instrumentation with ASTM F1717 methodology. Non-fusion instrumentation consisted of 5.5 mm titanium rods joined with wedding-band connectors at the middle of the 76 mm span between two polyethylene blocks. Rods were anchored to pedicle screws that had been placed in the blocks and offset appropriately for wedding-band connectors. Two experimental groups (fusion and non-fusion spinal instrumentation; n = 5/group) were tested in static compression bending (ie, flexion-extension). Stiffness, yield and ultimate strength were calculated from force-displacement data. Data were analyzed statistically using a Students t-test with the level of significance set at P < .05.

Results:

Stiffness of non-fusion instrumentation was significantly greater than fusion instrumentation at 48.0 ± 1.9 and 43.4 ± 0.3 N/mm, respectively (P < .01). Yield strengths were similar between non-fusion and fusion instrumentation at 475 ± 60 and 457 ± 17 N, respectively (not significant). Ultimate strength of non-fusion instrumentation was greater than fusion instrumentation at 1,080 ± 9 N versus 1,008 ± 6 N, respectively (P < .01).

Conclusion:

For non-fusion instrumentation there were significant increases in stiffness (11%) and ultimate strength (7%) when compared with fusion instrumentation. This study helped to establish a baseline for biomechanical testing of non-fusion spinal instrumentation, and show that non-fusion instrumentation can carry larger loads with a higher stiffness than fusion instrumentation.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577ci

A087: Spatial and Temporal Response of Myelinating Cells to Traumatic Spinal Cord Injury in Animal Studies: A Systematic Review

Abstract

Introduction:

Damage to oligodendrocytes (OLs) and myelin are one of the major contributors to functional loss following spinal cord injuries (SCI). Understanding temporal and spatial response of OLs and other myelinating cells including progenitor cells and Schwann cells in animal models can help us comprehending complex pathophysiological responses in human. Here we conducted a systematic review to reach an evidence-based knowledge about myelinating cells fate after SCI.

Material and Methods:

We searched MEDLINE (1946 to January 2016) and EMBASE (1974 to January 2016) databases, without applying time or language limitation. In addition, we performed hand-search through the relevant papers.

Results:

After injury, a large number of oligodendrocytes (OLs) and progenitor cells die as early as 15 minutes post injury, initially due to necrosis and then through apoptosis. This loss then extends to the areas distal from lesion by two weeks. On the other hand, progenitor cells proliferate and peak around the first week after injury at the lesion borders to compensate the OL population. Followed by increased number of progenitor cells, they instigate to display OL properties. Until, almost the fourth week post injury when the number of OLs approaches the normal controls. For many years it has been thought that progenitors that express NG2 marker can only differentiate into OLs. However, evidences show a temporal and spatial transition in progenitor cells fate. Evidences based on real-time labelled progenitor cell show between 72 hours to 7 days, NG2+ cell give rise to a population of cells with phagocytic properties.

Conclusion:

Being post-mitotic, OL are not able to proliferate following SCI to preserve their population. However, a portion of progenitor cells in coordination of Schwann cells (in severe injuries) make up the OL population. Recapitulating this response could be an interesting avenue toward more efficient therapeutics.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577cj

A088: Efficacy of Hydrogels for Repair of Traumatic Spinal Cord Injuries: A Systematic Review and Meta Analysis

Abstract

Introduction:

The disability of central nervous system (CNS) for regeneration imputed to inhibitory environment of CNS after injury. Hydrogels belong to a class of water-insoluble polymers and may be either homopolymers or copolymers. Hydrogel scaffolds are shown to assist in tissue regeneration by providing physical and chemical cues to direct axonal regeneration and cellular infiltration into the lesion, or implant site in the spinal cord. However, no optimum protocol has been developed for application of hydrogels for repair of TSCI. Here, we evaluated the efficacy of hydrogels for repair of TSCI through conducting a systematic review and meta analysis.

Material and Methods:

We searched PubMed and EMBASE with no temporal or linguistic restrictions. In addition, hand-search was performed in the bibliographies of relevant studies. Controlled animal studies used hydrogels without incorporation of cells or any other therapeutic agents were included.

Results:

The most common synthetic hydrogels has been studied for repair of TSCI are poly(2-hydroxyethyl methacrylate), poly[N-(2-hydroxypropyl)-methacrylamide], poly(ethylene glycol), poly(?-hydroxybutyrate), also, natural origin hydrogels including alginate, chitosan, collagen, fibrin, agarose, hyaloronic acid, starch, Matrigel and NeuroGelTM. In addition, alginate, blends of agarose/methylcellulose and hyaloronan/methyl cellulose and self-assembling peptides are injectable hydrogels recently evaluated for regeneration of TSCI. The effectiveness of hydrogels on repair of TSCI after injury has been evaluated based on axonal regeneration, functional recovery and reduction of scar formation. In addition, the effect of hydrogels on angiogenesis as well as inflammation and integration of implanted scaffold with host tissue have been assessed. Improved functional recovery after implantation of hydrogels was found to be higher in transection than contusion/compression injury model. Additionally, functionalized hydrogels were more efficient in repair compared to non-functionalized ones.

Conclusion:

Hydrogels may be an appropriate platform to encourage regeneration of the injured spinal cord. There is a hope that these gels along with our deepening understanding of the pathophysiology of TSCI will result in advances in the treatment of TSCI in human subjects in the next few years.

Acknowledgement

This project has been support by the Sina Trauma and Surgery Research Center, Tehran University of Medical Sciences (fund number: 94-02-38-29150).

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577ck

Lumbar Surgery Complications
A089: Economic Impact and Clinical Outcomes of Liberal Blood Transfusion in Spine Surgery

Abstract

Introduction:

Blood loss is a major concern in spine surgery. Blood transfusion promotes oxygen delivery and tissue perfusion during long, complex surgeries, yet carries with it rare but notable risks. The hemoglobin (Hb) trigger—the Hb value that initiates clinician administration of packed red blood cells (PRBCs)—is frequently used to evaluate physician compliance with existing transfusion guidelines. Randomized clinical trials have demonstrated similar or improved outcomes among patients receiving blood transfusions using a restrictive Hb trigger—defined as an intraoperative Hb level of <10 g/dL intraoperatively or <8 g/dL postoperatively—versus a liberal Hb trigger (≥10 g/dL intraoperatively or ≥8 g/dL postoperatively) in cardiac and hip surgery. To the authors’ knowledge, no study has examined the associated morbidity and financial impact of liberal transfusions within spinal surgery. We thus aimed to determine the perioperative clinical outcomes and costs associated with liberal versus restrictive transfusion triggers among spine surgery patients.

Material and Methods:

The surgical billing database at our institution was queried for inpatients discharged following spinal surgery between 2008 and 2015, yielding 33,043 patients. Patients were stratified into eight groups according to the spine surgical procedure performed. The values used were the reported institutional acquisition cost ($220/unit) and a mean estimated activity-based cost ($760/unit) based on a Society for the Advancement of Blood Management report. Outcomes considered included mortality, in-hospital morbidity, total costs, and length of stay.

Results:

A total of 6,931 patients met the inclusion criteria. PRBC transfusions occured in 2,374 patients (at least 1 unit of PRBCs), yielding an overall transfusion rate of 34.3%. Compared to the other surgical groups, most PRBC use occurred within posterior lumbar fusion patients. The mean intraoperative Hb trigger was 10.1 (SD = 1.7) g/dL and the mean postoperative Hb trigger was 10.1 (SD = 2.1) g/dL. For the 2,374 patients that were transfused with PRBCs, 1420 (59.8%) received a postoperative PRBC transfusion with a liberal postoperative Hb trigger (≥8 g/dL) while 529 (22.3%) received an intraoperative PRBC transfusion with a liberal intraoperative Hb trigger (≥10 g/dL). Logistic regression analysis revealed that patients with a nadir Hb of 8-10 g/dL transfused with PRBC had an independently higher risk of perioperative morbidity (odds ratio [OR] = 2.12; 95% confidence interval [CI], 1.24-3.64; P = .006). The additional cost when comparing restrictive and liberal transfusion triggers was estimated to be between $1,330,439 and $4,596,062 (58.7% of the estimated total cost of PRBC transfusion), with the cost varying by surgery type. When comparing liberal and restrictive PRBC transfusion triggers, an estimated additional $202,675 to $700,151 in institutional costs were incurred each year among patients undergoing spine surgery.

Conclusion:

Patients with a nadir Hb of 8 to 10 g/dL who were transfused had higher perioperative morbidity, even after adjusting for potential confounders. The additional cost incurred from liberal transfusion trigger reliance ranged from an estimated $202,675 to $700,151 annually. These findings point to a potential area for clinicians and institutions to improve patient outcomes and reduce costs.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577cl

A090: Obstructive Sleep Apnea is Associated with Increased Complication Rates in Elective Spine Surgery

Abstract

Introduction:

Obstructive sleep apnea (OSA) is a significant sleep disorder that is often associated with poor health status. The prevalence of OSA is increasing in the United States. Some studies have shown it to be associated with poorer post-operative outcomes following surgical procedures. Little information exists characterizing inpatient outcomes in patients with OSA undergoing elective spine surgery.

Material and Methods:

Utilizing data from the National Inpatient Sample from 2002 to 2012, an estimated 78,613 patients with OSA undergoing elective spine surgery for degenerative lumbar and cervical disease were selected and compared to 4,295,538 patients undergoing the same procedures. Post-operative outcomes including: complications of surgery, inpatient mortality, and length of stay were assessed for both groups. Complications were classified as major or minor. Major complications included acute myocardial infarction, cardiac arrest, septicemia, septic shock, stroke, and pulmonary embolism. Minor complications included deep vein thrombosis, pneumonia, surgical complications, post-operative anemia, and urinary tract infections. Finally, a comparison of total hospital charges between the two cohorts was made.

Results:

Patients with OSA were, on average, five years older than those without OSA (P < .001) and had a larger mean comorbidity burden (2.52 comorbidities compared to 1.16; P < .001). Procedures performed included primary and revision spinal fusions and posterior decompressions. OSA was associated with an increased rate of post-operative complications (3.2% compared to 1.4%; P < .001). OSA was an independent risk factor for major complications based on multivariate logistic regression analysis (OR = 1.31; 95% CI 1.25 to 1.38; P < .001). A slight increase in inpatient mortality rates was seen in the OSA group (0.3% compared to 0.2%; P < .001). Average length of stay was slightly longer for patients with OSA (3.7 days compared to 3.2 days; P < .001), and overall hospital charges were significantly increased in the OSA cohort (56,560$ compared to 37,405$; P < .001).

Conclusion:

Patients with obstructive sleep apnea often have multiple concomitant comorbidities and are at increased risk of experiencing a more difficult post-operative course following elective spine surgery. Both surgeons and patients should be aware of these risks while weighing the risks and benefits of surgery.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577cm

A091: Rates of Aspiration Pneumonia and Various Dysphagia Stages after Cervical Fusion Procedure

Abstract

Introduction:

Dysphagia is a well-known complication after cervical spine surgeries but incidence reporting and risks vary. Although usually transient, dysphagia can be potentially life-threatening if it leads to aspiration pneumonia or upper respiratory tract infection. There is a significant need for more specific and reliable data locating the origin of the swallowing dysfunction. Using a large medical record database that more closely and accurately models the American population as a whole, the aim of this study was to analyze the incidence of aspiration pneumonia, specifying in which stage of swallowing—oral, pharyngeal or esophageal—the dysphagia was occurring.

Material and Methods:

Patients undergoing Anterior Cervical Discectomy and Fusion (ACDF) and Posterior Cervical Fusion (PCF) from 2007-2014Q2 were selected from records of the nationwide private insurance provider Humana within the Pearl Diver patient records database. ICD-9 diagnosis codes (International Classification of Diseases 9th edition) were used to reveal incidence of post-operative dysphagia by type—oral, pharyngeal and esophageal—within one year of surgery. Cases of pre-existing swallowing conditions were excluded from the analysis. The data was also examined for incidence of patients who developed aspiration pneumonia within one month after dysphagia.

Results:

From 21701 ACDF patients (11360 female; 10341 male) 15% developed postoperative dysphagia. Fourteen percent of women who underwent ACDF acquired some degree of swallowing dysfunction while 16% of men had dysphagia. Patients with postoperative dysphagia of any type were 13.7 times more likely (P < .0001) to develop aspiration pneumonia than ACDF patients who did not have dysphagia. Of the 3,261 patients who developed dysphagia 5% proceeded to aspiration pneumonia. Pharyngeal and unspecified dysphagia were the most contributable to aspiration pneumonia. With a chi-square statistic of 7.2 and P < .5, these dysphagia types were statistically independent, while other types of dysphagia did not occur alone. Among PCF patients (3255; 1419 female and 1835 male) 18% had postoperative dysphagia. Eighteen percent of men and women who underwent PCF had difficulty swallowing after surgery. PCF patients with dysphagia of any type were 9.3 times more likely (P < .0001) to develop aspiration pneumonia than patients who did not have dysphagia. Of the 575 patients who developed dysphagia, 12% went on to develop aspiration pneumonia. Unspecified and pharyngeal were the most common types of dysphagia leading to aspiration pneumonia, though they were not statistically independent.

Conclusions:

The results of this study illuminate that PCF is more likely than ACDF to cause some type of patient dysphagia. Furthermore, in our study among ACDF patients men were more prone to dysphagia than women, while there was no difference in gender for PCF patients. Pharyngeal and unspecified dysphagia types led to the most instances of aspiration pneumonia. These findings are critical for physicians evaluating the severity of their patients’ dysphagia and should be considered when deciding if treatment is needed.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577cn

A092: Predictors of Blood Transfusion in Posterior Lumbar Spinal Fusion: A Canadian Spine Outcome and Research Network (CSORN) Study

Abstract

Introduction:

The rate of posterior lumbar spinal fusion (PSF) surgery has increased significantly over the past few years. It remains the most common surgical procedure used to stabilize the spine for a variety of spinal pathologies; however, the impact of blood loss requiring blood transfusions remain a significant concern in this population. The purpose of this study was to identify patient related, disease related or procedure related predictors of postoperative blood transfusions.

Material and Methods:

This is an ambispective analysis of data from the Canadian Spine Outcomes and Research Network (CSORN). Patients who underwent PSF between 2008 and 2015 were identified. Multivariate analysis was used to identify predictors of blood transfusion from routinely collected patient information including both preoperative and intraoperative items.

Results:

Of the 772 patients identified to have undergone PSF, 18% required blood transfusion. Overall, there were 54.8% females and the mean age was 60 years. Multivariable logistic regression analysis revealed five significant predictors of blood transfusion: American Society of Anesthesiologist class (ASA), operative time, number of level fused, sacrum involvement and open posterior approach. The odds of transfusion for those with ASA class greater than 1 were six times the odds for those with ASA class 1 (OR 6.1, 95% CI 1.4-27.1, P < .018). For each 60 minutes increase in operating room time, the odds of transfusion increased by 4.2% (OR 1.007, 95% CI 1.004 -1.009, P < .001). Moreover, the odds of transfusion when more than one level were fused was 6 times the odds for one level fusion (OR 5.8, 95% CI 2.6-13.2, P < .001). Also, when the fusion was extended to the sacrum the odds for blood transfusion were three times higher (OR3.2, 95% CI 1.8-5.8, P < .001). Finally, the odds of transfusion for patients undergoing open posterior approach were 12 times the odds for those who had minimal invasive surgery (OR 12.5, 95% CI 1.6-97.4, P < .016). In addition, patients receiving transfusions who underwent lumbar fusion were more likely to have extended hospital stay.

Conclusion:

ASA > 1, prolonged operative time, multilevel fusion surgery, sacrum involvement and open posterior approach were significant predictors of blood transfusion in posterior lumbar spinal fusion.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577co

A093: “After-Hours” Emergent Spine Surgery: Perhaps We Should Think Twice?

Abstract

Introduction:

‘After-hours’ emergent spinal surgeries are frequently necessary, and often performed under sub-optimal conditions. The consequences of performing these often complex surgeries under such conditions on post-operative outcomes are unknown.

Methods:

One thousand four hundred and forty patients underwent emergent spinal surgery at a single institution between 2009-2013. Surgery was defined as ‘In-Hours’ if completed between 7h00 and 16h00. Surgery was defined as ‘After-Hours’ if more than 50% of the operative time was between 16h01 and 6h59, or if it was performed over the weekend. Data on demographics, diagnosis, surgical intervention, Spine Surgical Invasiveness Score (SSII), operative start time and end time, intra-operative blood loss (IOBL) and post-operative outcome measures (adverse events (AE), mortality, length of stay) were prospectively collected.

Results:

664(46.1%) procedures were performed “After-Hours”. OR time and IOBL were similar between groups (P > .05). % of the patients operated “After-Hours” experienced at least an AE compared to % for the “In-Hours” group (P = .0). The number of intra-operative AE/patient was significantly higher in the “After-hours” group (versus, P = .0). ‘After-hours’ designation was an independent predictor of AE on multivaria analysis (adjusted OR 1.30, 95% CI, 1.02-1.66, P = .034). In-hospital mortality doubled in patients who had surgery after hours (4.4% versus 2.1%, P = .01). On multivariate analysis, “After hours” surgery showed a borderline association with in-hospital death (adjusted OR 1.99, 95% CI 0.98-4.06, P = .056). Length of stay was longer in the “After-hours” group (median 1IQR 7-2 versus 1, IQR 7-2, P = .014). However, on multivariate analysis, association between LOS and “After-hours” was not significant (adjusted OR 1.63, 95% CI -0.83-4.10, P = .194).

Conclusion:

Emergent spine surgery performed ‘after-hours’ is associated an increased in peri-operative adverse events. Higher mortality System changes to facilitate ‘In-Hours’ surgery could mitigate against the adverse outcomes associated with’After-Hours’ surgery.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577cp

A094: Post-Operative Venous Thromboembolic Events in Patients Undergoing Lumbar Spine Surgery

Abstract

Introduction:

Venous thromboembolic events (VTEs) including deep vein thrombosis (DVT) and pulmonary embolism (PE) are preventable complications associated with significant morbidity and mortality after spine surgery. Previous literature focused on timing and incidence of post-operative VTEs after lumbar surgery is limited. The aim of this study was to investigate incidence and risk factors associated with venous thromboembolic events after lumbar spine surgery using a large nationwide sample group.

Materials and Methods:

Patients who underwent first time isolated lumbar surgery between 2007 and 2014 including any of five types of single or multi-level lumbar procedures were identified using the PearlDiver patient database (PearlDiver Technologies, Inc., Fort Wayne, IN, USA) from private insurance provider Humana Inc. ICD-9 diagnosis codes (International Classification of Diseases 9th edition) were used to search patient records and determine incidence of VTEs among surgery types, patient demographics and comorbidities. Complications including DVT and PE were queried each day from the day of surgery to post-operative day 7 and for periods 0 to 1 week, 0 to 1 month, 0 to 2 months and 0 to 3 months post-operatively.

Results:

64,892 patients within the Humana insurance database received lumbar surgery between 2007 and 2014. Overall VTE rate of 0.9% (N = 608) was seen at 1 week, 1.8% (N = 1190) at 1 month and 2.6% (N = 1667) at 3 months postoperatively. Among patients that developed a VTE within one week post-operatively, 45.3% (N = 267) had a VTE on the day of surgery. Patients with one or more identified risk factors had a VTE incidence of 2.73%, compared to 0.95% for patients without risk factors (P < 0.001). Risk factors associated with the highest VTE incidence and odds ratios were primary coagulation disorder (10.01%, OR 4.33), extremity paralysis (7.49%, OR 2.96), central venous line (6.70%, OR 2.87) and varicose veins (6.51%, OR 2.58).

Conclusions:

This study identifies several patient comorbidities that were independent predictors of post-operative VTE occurrence after lumbar surgery. Clinical VTE risk assessment may improve with increased focus towards patient comorbidities rather than surgery type or patient demographics. Patients undergoing lumbar surgery may be at an increased risk of post-operative VTE occurrence on the day of surgery. We believe our findings on incidence and timing of venous thromboembolic events after lumbar surgery will provide useful information to clinicians when assessing patient risk in the pre- and post-operative periods.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577cq

Trauma Lumbar
A095: Is the Transpedicular Bone Grafting an Effective Technique for Prevention of Kyphosis in Thoracolumbar Fractures?

Abstract

Introduction:

Fractures of the thoracolumbar spine represent 90% of all spine fractures, the thoracolumbar burst fractures (Type A fractures) are the most common in the spine and important cause of posttraumatic kyphotic deformity. The cause of this problem appears to be the structural and mechanical deficiency of the anterior column following indirect fracture reduction by posterior fixation.

Objective:

The objective of this study was to evaluate the effects of transpedicular intracorporeal grafting associated to short-segment transpedicular fixation, on kyphosis progression in patients with thoracolumbar burst fracture type A3/A4.

Methods:

Fifty-nine consecutive patients with thoracolumbar burst fracture treated with short-segment transpedicular mono-axial screw fixation. Patients were simply divided into transpedicular grafting (TPG) (n = 35, A3 = 20, A4 = 15) and non-TPG (n = 24, A3 = 19, A4 = 5). The average follow-up was 21.1 ± 4.2 (range 16–26) months for the entire study group: 22.1 ± 4.5 months for the TPG group and 20.2 ± 4.8 months for the non- TPG group (P = .49).

Results:

The global mean kyphosis angle before surgery was 21.93 ± 3.92°, with 22.06 ± 3.55° in the TGP group and 20.75 ± 4.68° for non-TGP; P = .93. The mean kyphosis angle after surgery for entire study was 9.21 ± 8.86°, with 8.70 ± 2.11° TGP and 14.08 ± 4.73° NON-TGP, (TGP vs non-TGP, P = .010). No obvious clinical complications in both group it was documented.

Conclusion:

Our findings demonstrate that transpedicular bone grafting associated to short-segment fixation in thoracolumbar burst fractures has cause a significant effect on prevention of kyphosis progression after surgery.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577cr

A096: Postoperative Evaluation of Vertebral Body Height Correction in Magerl A Thoracolumbar Fractures

Abstract

Introduction:

Magerl A thoracolumbar fracture is caused by axial compression resulting in loss of vertebral body height (VBH). The main objective of treatment is to restore the VBH in order to limit the subsequent loss of correction, which occurs predominantly within the intervertebral disc space. The analysis of the quality of the reduction in the operating room is routinely made on plain radiographs only. Several studies have analyzed many preoperative parameters of interest including the Cobb angle. However, no prior study has prospectively assessed the postoperative correction of VBH. Our purposes were to (1) compare the relevance of measurements on plain radiographs and computed tomography (CT) scans to assess the postoperative correction of VBH, (2) analyze inter and intraobserver reliability of these two methods and (3) evaluate the correlation between radiographic Cobb angle, radiographic intervertebral disc space height and the VHB measurement using CT scan.

Materials and Methods:

We prospectively analyzed 40 Magerl A thoracolumbar fractures which required surgical treatment with posterior short-segment pedicle-screw fixation without fusion. Postoperative lateral radiographs and CT scans were reviewed independently by two spine surgeons and one musculoskeletal radiologist, and repeated at two separate times for one surgeon. The main measure was the “vertebral body reduction coefficient” (VBRC) defined as the ratio between the height under the maximal bone depression and the height in the middle of the vertebral body. Intraclass correlation coefficients (ICCs) were utilized to determine inter and intraobserver reliability. Spearman’s correlation coefficients were used to assess the association between the Cobb angle, the disc space height and the VBH.

Results:

The average age at the time of fracture was 37 ± 19 years old. For each observer, the mean value of radiographic VBRC was significantly different from CT scan VBRC. For the spine surgeon 1, mean value of VBRC was respectively 0.82 ± 0.12 and 0.67 ± 0.1 for plain radiographs and CT scans (P < .0001). For the spine surgeon 2, in the first series of measurements, mean value of radiographic VBRC was 0.82 ± 0.07 and 0.69 ± 0.1 for CT scans (P < .0001). In the second series of measurements, it was respectively 0.81 ± 0.06 and 0.69 ± 0.1 for plain radiographs and CT scans (P < .0001). For the musculoskeletal radiologist, mean value of radiographic VBRC was 0.8 ± 0.12 and was 0.66 ± 0.1 for the CT scan VBRC (P < .0001). The interobserver reliability was fair for plain radiographs and substantial for CT scan. The intraobserver reliability was respectively moderate and substantial. Neither radiographic Cobb angle nor radiographic intervertebral disc space height is correlated to the CT scan VBH measurement.

Conclusion:

Radiographic evaluation of postoperative VBH is incorrect, unreliable and no radiographic parameter is correlated to CT scan measurements. Improvement regarding development of techniques of vertebral body reconstruction and imaging with three-dimensional reconstruction embarked in the operating room will greatly benefit this type of fracture.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577cs

A097: Impact of Fragments Displacement on Surgical Treatment of Thoracolumbar Fractures: A Retrospective Radiological Analysis

Abstract

Introduction:

Thoracolumbar burst fractures represent an everyday challenge in the choice of the appropriate surgical strategy. The Load Sharing Classification (LSC) laid foundations for a scoring system able to indicate which fractures, fixed by short-segment posterior-only pedicle screws constructs, would need for longer instrumentations or an anterior column support. We retrospectively analyzed all the thoracolumbar fractures surgically treated, quantifying the vertebral body’s comminution so as to identify an additional parameter which can highlight the need for an anterior support when posterior fixation alone may be inadequate.

Methods:

One-hundred-twenty-one patients undergone posterior fixation for unstable thoracolumbar burst fractures were clinically and radiologically assessed. Supplementary anterior fixations were performed in cases of posterior instrumentation failure, impending failure determined on radiological and clinical evidences or symptomatic loss of kyphosis correction. The segmental kyphosis angle was calculated according to the Cobb method. The displacement of fracture fragments was obtained from the sum of the adjacent endplates areas divided by two and subtracted to the area enclosed by the maximum contour of vertebral fragmentation. The percentage of displacement (“spread”) derived from the ratio between this subtraction and the sum of the adjacent endplates areas divided by two.

Results:

In addition to the LSS the spread showed to be a quantitative measurement of vertebral body fragments displacement, which is easily reproducible with the current CT imaging technologies. There were no mechanical failures in those injuries treated only with posterior fixations showing a preoperative spread below 62.7%, while spreads superior to 100% required a supplementary anterior fixation. Most of the patients in the “grey zone” (between 62.7% and 100%) needed for an additional anterior support because a Grade of Kyphosis Correction (GKC) ≥ 10° had to be reached. Analysis of variance (ANOVA) showed that the effect of preoperative kyphosis (P < .001), LSS (P = .002) and spread (P < .001) on the surgical treatment (posterior or circumferential) were significant.

Conclusions:

Together with the Load Sharing Score (LSS) (P = .001) and the preoperative kyphosis (P < .0001) the spread (P = .005) was found to be an additional tool which could help in addressing the surgical strategy, providing an objective, entirely quantitative, reproducible and distinctly preoperative indicator.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577ct

A098: Could Intermediate Screw in Thoracolumbar Fracture Fixation Save Motion Levels? Comparative Study between Long Segment and Short Segment with Intermediate Screw Fixation

Abstract

Introduction:

Thoracolumbar fractures are commonly managed by posterior pedicle screw fixation. Controversy remains about the number of levels involved in the fixation as the stability of the short segment fixation remains questionable. Recently, it has been shown that application of intermediate screw in the fractured vertebra improves the biomechanical stability of the short segment construct. The aim of this study is to compare the outcome of long segment fixation (LSF) versus short segment fixation with intermediate screws (SSFIS) in the management of the thoracolumbar burst fractures.

Material and Methods:

Fifty patients with thoracolumbar burst fracture (T11-L2) type A3 and A4 AOSpine classification with a Thoracolumbar Injury Classification and Severity (TLICS) Scale of more than 4 were treated between 2009 and 2014 with posterior pedicle screw fixation. The patients were divided into two groups according to the number of instrumented levels. Group 1 included 25 patients treated with LSF (two levels above and two levels below the fractured level) while group 2 included 25 patients treated by SSFIS (one level above and one level below with 2 intermediate screws in the fractured level). The patients were evaluated for local kyphotic angle (LKA) correction and maintenance, anterior vertebral body height (AVH) compression, visual analogue scale (VAS) for back pain and treatment related complications. Construct failure was defined as screw pullout or instrument breakage.

Results:

The two groups were similar as regard to age, sex, fractured levels, fracture type, TLICS score, pre-operative local kyphotic angle and anterior vertebral body height compression. Post-operative correction of the local vertebral compression assessed with LKA and AVH significantly improved in both groups compared to the pre-operative degree while there was no significant difference in the two groups in early post-operative or follow up regarding the degree of correction and its maintenance. No construct failure or major treatment related complication were encountered in both groups with significant reduction of VAS in both groups between early post-operative and late follow up.

Conclusion:

Intermediate screw applied in the fractured level in management of thoracolumbar burst fracture improves the correction and maintenance of local kyphosis in short segment fixation similar to long segment construct with saving vertebral motion levels from being fixed. More randomized controlled and multicenter studies are needed to support these findings.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577cu

A099: Influence of Insurance Status on the Outcome and Length of Work Incapacity in Patients with Surgically Treated Fractures of the Thoraco-lumbar Junction

Abstract

Introduction:

Suffering a fracture of the thoraco-lumbar junction with need for combined dorsoventral stabilization constitutes an impairment for the patient. Neurological deficits and palsies are possible. Remaining disorders and pain are reported differently and lead to work incapacity for a certain length of time.

Material and Methods:

We analyzed 111 patients suffering a fracture of the thoraco-lumbar junction with need for combined dorsoventral stabilization. We studied outcome, remaining neurological deficits, pain and length of work incapacity. Subgroup study involved privately insured and patients with employer’s liability insurance coverage (ELIC).

Results:

Patients with employer´s liability insurance coverage seemed to be more restricted than patients lacking this kind of insurance coverage. Work incapacity after surgery was 10,36 months, being 6,29 months more compared to other patients (P < .0001; T-Test). Additionally, pain was reported as being more intense than in the patients without ELIC.

Conclusion:

Insurance status seems to be a strong predictor for the duration of work incapacity following injuries to the thoracolumbar spine.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577cv

A100: Short-Segment Fixation in Type C AO Thoracolumbar Fractures with Neurological Deficit: Survival Time of Paraplegic Patients Under Workers’ Compensation

Abstract

Introduction:

Spine fractures are common injuries in trauma population and the thoracolumbar junction (T10-L2) is the most frequently affected segment. In general, neurological impairment as a result of a spine fracture implies surgical treatment, in order to achieve decompression of the neural elements, as well as fixation of the affected vertebral levels, due to traumatic or surgery-induced spinal instability. Short-segment posterior fixation allows us to obtain spinal stability and neural decompression preserving healthy mobile segments, with shorter operative times, reduced intraoperative blood loss and associated costs. There is a lack of information in the literature regarding the management and follow-up of paraplegic patients due to thoracolumbar spine fractures treated with short-segment constructs. The purpose of this study is to describe the survival time of the short-segment fixation in patients under a workers’ compensation program, who underwent surgery after a thoracolumbar spine fracture with neurologic impairment.

Material and Methods:

We reviewed the medical records and imaging of patients with AO Type C thoracolumbar (T10-L2) spine fractures, with severe motor neurological impairment (ASIA Impairment Scale (AIS) A, B and C), treated in our center with a short-segment spinal fixation (mono or bi segmental) between 1988 and 2011, with a minimum follow up of 5 years. We excluded patients operated with hybrid instrumentations (ie, combination of screws, hooks and/or cables), with incomplete clinical records, operated elsewhere and those who died during the initial admission after the accident. Survival time of the short-segment fixation was estimated through a Kaplan Meier analysis, considering as a response of interest, the time elapsed between the date of the surgery and the date of the reoperation due to failure of the construct.

Results:

A total of 17 patients met the previously described inclusion criteria and hence were included in our study. The mean age was 34.59 years (SD = 10.24) and 88.24% of the group were males. The average follow-up was 17.24 years (SD 6.18). The main mechanism of injury was fall from a height. The most frequently injured levels were T11-T12 and T12-L1 with nine and five cases, respectively, while T12 was the predominant neurologic level of injury (NLI), with nine cases. Fourteen patients presented complete paraplegia (AIS A) on admission, while two presented AIS B impairment and the remaining one had an AIS C injury. At the end of the follow-up period, only two patients with AIS B impairment presented neurological recovery to AIS C and D respectively. Eleven patients were able to return to some type of work activity. We identified no patients with failure of the short-segment construct during the studied period (100% survival in 14 years).

Conclusion:

The survival time of the short-segment fixation was a 100% in 14 years. We can hypothesize that short-segment constructs are a viable alternative for the treatment of thoracolumbar spine fractures, even in patients with severe neurologic impairment.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577cw

Novel Concepts
A101: Spine Sagittal Balance Characterization in Professional Soccer Players

Abstract

Introduction:

Human spine is composed of physiological curvatures in the sagittal plane. Specific sports practices can modify these curvatures aiming a better adaptation. Non-harmonious changes in the spine sagittal plane increase the risk of spinal pathology. Soccer is the most practiced sport in the world. Low back pain (LBP) is one of the most frequent complaints in professional soccer players, with impact on the quality of training and the final performance. With this work, the authors aim to characterize sagittal balance in professional soccer players, compare them with the general population and establish a relation between the values of sagittal balance and spinal symptoms.

Material and Methods:

37 soccer players of the 1st and 2nd Portuguese Soccer League and 20 individuals from the general population between 18 and 35 years old were recruited. In the clinical and physical activity evaluation were applied the Oswestry Disability Index 2.0 (ODI) and the International Physical Activity Questionnaire (IPAQ short-form), respectively. Radiographic evaluation consisted in the interpretation of radiographs of the spine in extra-long film in all participants. Surgimap ® software was used and the following parameters were measured: pelvic incidence (PI), pelvic tilt (PT), sacral slope (SS), sagittal vertical axis (SVA), lumbar lordosis (LL) and thoracic kyphosis (TK). Sagittal balance values were grouped into categories (low, normal, high) according to reference values for the general population.

Results:

Soccer players have lower radiographic values of sagittal balance compared to the control group. However, only the PT has a statistically significant difference and a practical impact (t(55) = −2.64 P = .011 g-Hedge = −0.82). The players subgroup with low PT does not have adaptive values of SS, LL and TK, as verified in the same control subgroup. LBP frequency is higher in soccer players (57% vs. 50%) but a statistical significant difference between the frequency of LBP and changes in the sagittal balance was not confirmed. LBP is more frequent in soccer players when there are changes (increased or decreased values) of PT, LL and TK. The ODI is negligible in both groups (soccer players, ODI = 5%; control group, ODI = 2.3%).

Conclusion:

Changes in physiological spinal curvatures are associated with an imbalance in the intervertebral stress distribution. In elite athletes, these changes are particularly important as they can have an impact in the final performance but also because athletes can have targeted functional training in order to prevent injuries. This study characterizes the sagittal balance in a group of soccer players. The reduction of PT verified, which results in the pelvis verticalization, can be explained by the large quadriceps femoris muscle core in this population. The frequency of LBP in soccer players is high when compared to the control group and the overall population (57%, 50%, 25%, respectively) and occurs more when the radiographic sagittal balance values are changed. However, it was not observed any association between radiographic values and low back pain.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577cx

A102: Biological Disc Replacement Combined with a Bio-resorbable Stabilization System: A Proof of Concept Study

Abstract

Introduction:

Biological disc replacement using tissue-engineered intervertebral discs (TE-IVD) offers an alternative therapy to traditional treatments for degenerative disc disease (DDD). Recently a composite annulus fibrosus (AF) / nucleus pulposus (NP) disc-like construct has been manufactured and validated in rat tail and beagle cervical spine models in vivo. While cell viability and integration into host tissue was encouraging, the intrinsic biomechanical properties were inferior to native IVDs and implant displacement occurred in several cases. The aim of this study was to investigate the biomechanical responses of composite TE-IVDs combined with a bio-resorbable stabilization system (BSS) to static compression in an ex vivo model utilizing canine cervical spines.

Material and Methods:

Cervical IVDs from skeletally mature beagles were obtained, washed, and separated into AF and NP tissues. Upon further dissection into small fragments, the tissues were digested in collagenase Type II at 37°C for 12 hours prior to being filtered and centrifuged. NP and AF cells were cultured individually to confluence. Alginate (3% weight/volume) was then seeded with the cultured NP cells (2.5 × 106 cells/ml) and injected into a predesigned mold. Each of the molded NPs was placed in a well of 24-well culture plate as a neutralized collagen gel solution (4 mg/ml seeded with 3 × 106 cells/ml) was pipetted around the NP component. All components were gelled at 37°C to create the AF and TE-IVDs were kept in culture for 4 weeks, facilitating collagen fibril alignment and contraction. Whole cervical spinal motion segments from skeletally mature beagles were dissected and the mechanical compatibility was assessed for each motion segment at different time points: (1) intact, (2) after discectomy, (3) after implantation of the TE-IVD and (4) after implantation of the TE-IVD and application of the BSS ventrally. Unconfined stress relaxation tests were performed up to 15% strain and their instantaneous and equilibrium moduli were calculated and reported normalized to the intact motion segment. One-way ANOVA was performed to determine statistical significance.

Results:

Intact motion segments showed an equilibrium modulus of 174 ± 36 kPa and an instantaneous modulus of 1760 ± 430 kPa. Mechanical properties from motion segments after discectomy, TE-IVD implantation without BSS, and TE-IVD implantation with BSS were all significantly lower than the intact motion segments. Results from all treatment groups were then normalized to their corresponding intact motion segment mechanics (n = 12). Motion segments after discectomy resulted in 14% ± 6% of the intact equilibrium modulus and 13% ± 4% of the intact instantaneous modulus. Application of the BSS in combination with the TE-IVD revealed a 2-fold increase in the equilibrium modulus and a 2-fold increase in the instantaneous modulus (P ≤ .05) over the groups with TE-IVD implantation only.

Conclusion:

The TE-IVD combined with a BSS prevents displacement of the TE-IVD while still allowing load sharing to the TE-IVD. Increasing the biomechanical properties of the TE-IVD can result in an implant with similar properties to native IVDs.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577cy

A103: A Correlation Analysis of Radiographic Spinopelvic Parameters in Health and Disease

Abstract

Introduction:

The vertebrae and the pelvis act as an interconnecting chain of segments. Change at one segment leads to a compensatory change in the adjacent segments. The spinopelvic radiographic variables are useful in identifying these compensations. Analyzing the chain of correlations amongst these variables can help in improving our understanding of compensatory mechanisms adopted by the patient in some commonly encountered spine pathologies. In our study, we aimed to identify the relative significance of these radiographic spinopelvic parameters and how they correlate to each other in patients with chronic low back pain and spondylolisthesis when compared to normal population.

Material and Methods:

The study was approved by our institute review board and the ethical committee. We included all the patients visiting our OPD with complaints of LBP for more than three months and giving consent for the study. All patients underwent a thorough clinical and radiological examination, to rule out any apparent cause of LBP. A total of 67 patients with LBP without any deformity were thus included in the study. We also included a second group of 79 patients with LBP with spondylolisthesis deformity. We excluded patients with spinal deformity (other than spondylolisthesis), fracture, infection, malignancy and with a history of previous spine surgery. Another age and sex matched group of asymptomatic volunteers (n = 75) were also recruited as a control group. All the patients and volunteers underwent a standardized lateral sagittal digital radiograph of the whole spine. The sagittal spinopelvic parameters were measured using the Surgimap spine software version 2.1.2 by a single observer. The parameters measured were PI, pelvic tilt PT, sacral slope SS, thoracic kyphosis TK, lumbar lordosis LL. Pearson correlation was used to find the correlation between the parameters.

Results:

In the asymptomatic group a significant correlation was found between SS-LL (r-0.817), PI-SS(R-0.813), PI-LL(r-0.692), PI-PT(r-0.589), LL-TK (r-0.505). The correlation among different spinopelvic parameters in patients with chronic low back pain is SS-LL(r-0.661), LL-TK(r-0.609), PI-SS(r-0.580), PI-LL(r-0.533), PI-PT(r-0.527). High correlation was found between, SS-LL(r-0.781), PI-SS(r-0.769), PI-LL(r-0.56), LL-TK(r-0.428), PI-PT(r-0.426), PT-LL(r-0.25) in spondylolisthesis group.

Conclusion:

Based on the results of our study we conclude that -The highest correlation was between sacral slope and lumbar lordosis among all the three groups. The relative extent of correlation between radiographically measured spinopelvic parameters differs in patients with chronic low back pain when compared to normal individuals. The relative extent of correlation between radiographically measured spinopelvic parameters in patients of spondylolisthesis matches that, observed in the normal population.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577cz

A104: Intraoperative Stress in Spine Surgery: Attending versus Resident

Abstract

Introduction:

Mental and bodily requirements for Orthopaedic Spine Surgeons include occupational skills and concentrativeness, along with a certain level of physical fitness and psychological stress resistance in case of complications during spine surgery. So far, no study has looked at the Spine Surgeons’ cardiovascular response and influence of physical and mental (psychological) stress during spine surgery in either the attending’s or resident’s position.

Material and Methods:

This study measured and evaluated stress-relevant cardiovascular parameters during 101 spine surgical procedures of a healthy 40-years old fellowship-trained Spine Surgeon with 12 years of work experience (BMI 25). A digital training computer (Polar Model RS300X), personal body weight scale, and room thermometer were used to record heart rate, calculate weight loss, calorie burn, and environmental temperature during surgery with special regard to the type of surgery, duration and subjective stress level (coded as: “easy”, “moderate”, or “difficult”) along with an analysis of intraoperative complications during procedures.

Results:

The average maximum heart rate as an attending surgeon (124 bpm) was significantly higher when compared the resident’s heart rate (99 bmp) during surgery (P < .05). The mean loss of body fluids (kilogram body weight) at an average room temperature of 20.4°C after surgery was -0.82 kg (0 to -2.3 kg). The mean loss of body weight (%) per hours was calculated with -1.12% at the attending versus -0.59% at the resident (P < .05). Higher metal workload and stress levels resulted in a higher physiological cardiovascular response, e.g. increased average maximum heart rate and duration of surgery “easy” (103 bpm, 1 h:51 min), “moderate” (125 bpm, 2 h:57 min), and “difficult” (131spm, 3 h:56 min)). There were six intraoperative complications (dural tears [n = 3], pedicel fracture [n = 1], excessive bleeding [n = 1], and unknown lumbar spinal nerve anomaly [n = 1]).

Conclusion:

For the first time this study evaluated the attending surgeon’s cardiovascular response during spine surgery in comparison to the surgical assistant’s (resident’s). Technically more demanding, complex procedures and longer operating hours resulted in a higher cardiovascular response of the attending surgeon than resident. The observed cardiovascular parameters during spine surgery are similar to those of an intense workout such as fast bicycling or intense circuit training. Long lasting surgeries can cause weight loss and mild dehydration (-2 to -5% of body fluids). In these situations and according to the literature, lack of fluid ingestion and mild dehydration is substantially worsening someone’s cognitive-, visual-, and motor skills. Thus adequate rehydration during surgery is helpful and might prevent intraoperative risks and complications related to possible physical exhaustion during prolonged, complex spine surgeries or in mentally stressful situations.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577da

A105: Factors that Impact Pedicle Screws Stability in Patients with Degenerative Diseases of Lumbar Spine

Abstract

Introduction:

Implant instability have a relatively high incidence in aged patients with degenerative diseases of lumbar spine. This problem is not resolved yet and it is essential to assess risk factors that may lead to implant instability while planning intervention. The objective of this study is to determine risk factors that may impact implant stability in patients with degenerative diseases of lumbar spine.

Materials and Methods:

This is a retrospective evaluation of 160 spinal instrumentations performed in case of spinal degenerative diseases of lumbar spine. Preoperatively patients underwent CT examination and bone density was measured in Hounsfield units (HU). CT scans utilized slice thickness 0.5 mm. Tube voltage was 120 kV, current 300 mA, auto mAs range 180-400; 1.0 sec/3.0mm/0.5x32, helical-pitch 21.0. Transpedicular fixation was used to treat patients either as a stand-alone technique or in combination with transforaminal interbody fusion. Also, if indicated, decompression of nerve roots and spinal cord was performed. Patients with suboptimal placement of pedicle screws and interbody implants were excluded from this study. Patients who underwent degenerative deformity correction and additional pelviosacral fixation were not included in this study. The duration of follow up was 18 months; patients underwent CT examinations at the period of 6, 12, 18 months after interventions. Cases with implant instability were registered and divided into partial and total implant instability. Logistic regression analysis was utilized to assess the relationship between implant instability rate and potential risk factors.

Results:

The following factors were taken into account assessing risk for implant instability formation: bone density measured in HU, number of fixed levels (the extension of fixation), presence of segments without fusion within fixed zone; bilateral facet joints removal and laminectomy to achieve decompression. The rate of implant instability was growing with bone density in HU getting decreased and a positive relation of implant instability frequency with the number of fixed segments was estimated. Additional significant factor for implant instability development was destabilizing decompression with bilateral facet joints removal. The influence of other factors was found to be negligible. The parameters of general logistic regression for implant instability rate were: B0 = 0.1483, P = .8568 (insignificant); B1 for bone density = −0.0226, P = .0001; B2 for bilateral facet removal = 1.0188, P = .0232; B3 for number of fixed levels = 1.5208, P < .0001. Goodness of fit of general model - Chi-square = 62.40129, P < .0001. Classification of cases – 78.75% correctly predicted, specificity and specificity of estimated model achieve 85.5% and 70% respectively. Regression residuals do not have significant difference from normal distribution (Chi-square, Anderson-Darling and Kolmogorov-Smirnov tests were applied).

Conclusion:

Apparently, surgical intervention should be planned thoroughly avoiding destabilizing overdecompression because this could be a significant contributing factor for the implant instability formation in future. Bone quality is the most significant contributing factor for implant stability that must be taken into account planning spinal instrumentation. If necessary, augmentation with bone cement must be performed in order to prevent implant instability formation. The extensiveness of fixation should be clearly justified as far as this is also significant factor that may influence implant stability.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577db

A106: Unilateral Spinous Process Non-Covering Hook Type Patient-Specific Drill Template for Thoracic Pedicle Screw Fixation: A Pilot Clinical Trial and Template Classification

Abstract

Introduction:

The pedicle screw system for posterior instrumentation to the thoracic and lumbar spine is the general method nowadays. But complications due to screw mal-positioning is still reported, and exact screw positioning needs radiologic confirmation which hazard The purpose of this study is to confirm that accurate thoracic pedicle screw position placed by the patient-specific drill template (PSDT) made by rapid prototyping (RP) and analyze of previously reported PSDT designs and its characteristics.

Material and Methods:

The preoperative spiral three-dimensional (3-D) CT scan (LightSpeed VCT, GE, USA) was performed on the thoracic spine with 0.625 mm slice thickness and 0.35 mm in-plane resolution. The images were stored in DICOM format and transferred to a workstation running MIMICS 17.0 software, 3-Matic 9.0 (Materialise company, Belgium) to generate a 3-D reconstruction template for the desired thoracic vertebra. The accurate trajectory and screw diameter and length were calculated with UG Imageware 12.1 (EDS Co., USA). The guide template was sterilized and used intra-operatively to assist with the placement of thoracic pedicle screws. After all of the pedicle screws was inserted. We performed the CT scan postoperatively to evaluate the position of thoracic pedicle screws. Using Imageware postoperative CT scan was compared with preplanned trajectory safety and accuracy. After all CBT screws were inserted, we performed a CT scan to evaluate the position of the screws. By using the Imageware program, the postoperative CT scan data were compared with the preplanned trajectory for the assessment of safety and accuracy. We stacked pre-CT and post-CT slices of axial and sagittal planes and measured the distance between the preplanned trajectory and the fixed screws. (Figure 3.) We reviewed 12 previous reports and classified by the shape and system of PSDT which met the inclusion criteria of the review.

Results:

In total, ten screws were placed using patient-specific drill guide template without violation of single laminar cortex. The drill guide template was fit to the lamina of the vertebra. There was no violation of the spinal canal or the cortex of pedicle by postoperative CT scans. The results of 13 PTSD type which included current study suggest that there is no significant difference in accuracy between the PSTDs.

Conclusion:

Using the unilateral Spinous Process Non-Covering Hook Type Patient-Specific Drill Template made by the RP provide us the accurate trajectory for thoracic vertebra and classification of PSDT in this study would be helpful for further study.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577dc

Basic Science Disc Regeneration
A107: Diffusion Characteristics of Human Annulus Fibrosus: A Study Documenting the Dependence of Annulus Fibrosus on Endplate for Diffusion

Abstract

Introduction:

Intervertebral disc being avascular depends on nutrition either from endplate or annulus fibrosus (AF). Role of endplate on disc diffusion had been extensively studied. However diffusion of human AF remains poorly understood due to lack of reliable techniques to study AF in-vivo & non-invasively. Present study for the first time evaluates the 24-hr diffusion characteristics of AF in radial, axial & circumferential directions.

Material and Methods:

25 discs from 5 healthy volunteers (age < 20 yrs) were studied. Diffusion over 24-hours following I.V gadodiamide injection (0.3mmol/kg) was studied at 10 min, 2, 4, 6, 12 and 24 hrs. Axial images at cranial, middle and caudal zones of the disc were obtained. Vertebral body and endplate signal intensities were measured in sagittal sections. 39 ROIs (24 in AF, 15 in Nucleus-pulposus) at each disc were analyzed. Peak enhancement percentage (EP max) and time to attain EP max (T max) were calculated. Radial (outer Vs inner AF), axial (cranial Vs caudal Vs middle zone) and circumferential diffusion were analyzed.

Results:

AF showed a biphasic pattern of diffusion with a characteristic “double peak”. Early peak was seen at 10mins (coinciding with T max of VB) and delayed peak at 6 hrs (coinciding with T max of nucleus pulposus) and characteristically noted after T max of endplate (2 hrs). Inner AF showed significant regional differences both at the early and delayed peaks but outer AF had no regional differences in the early peak. In axial direction, both outer and inner AF showed maximum EP at middle zone followed by caudal and least at cranial zone.

Conclusion:

Annulus fibrosus characteristically showed a “double peak” pattern of diffusion. Both the peaks had different characteristics confirming two different sources of nutrition. An initial peak was contributed by peri-annular vascularity and delayed one via endplate from vertebral body. The fact that even AF depends on endplate for nutrition, help us to better understand the complex nutritional pathways of inter-vertebral discs.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577dd

A108: Comparison of the Stemness Potential and Response to Inflammation of Human Intervertebral Disc Cells, Adipose- and Bone Marrow-Derived Stem Cells

Abstract

Introduction:

The intervertebral disc (IVD) has a poor ability of healing. Nevertheless, the presence of resident progenitors having stemness features in the three main anatomical sites of the IVD, the nucleus pulposus (NP), the annulus fibrosus (AF) and the cartilaginous endplate (EP) was reported in few studies. These progenitors represent an alternative potential reservoir of specialized cells for tissue repair and homeostasis. In general, the role of mesenchymal stem cells (MSCs) in the maintenance of tissue homeostasis resides in their ability to secrete bioactive molecules in inflammatory condition, but the trophic and immunomodulatory role of NP, AF and EP cells and progenitors, to our knowledge, was not assessed anymore. Aims of this study are to characterize human cells from NP, AF and EP for their stemness features and to investigate their response to an inflammatory environment in term of ability to produce trophic factors and modulate the inflammation in comparison with MSCs harvested from bone marrow (BMSCs) and subcutaneous adipose tissue (ASCs).

Material and Methods:

NP, AF and EP cells from lumbar IVD were characterized for their CFU-F ability, immunophenotype, adipo-osteo-chondro-differentiative potential and stemness marker (NANOG, POU5F1) expression. After stimulation with IL-1β, the release of pro/anti-inflammatory mediators (IL-10, IL-6, IL-1Ra, TNFα) and the expression of growth factors (VEGFA, TGFB1), MMPs (1-3-13) and TIMPs (1-3) were evaluated, using ASCs and BMSCs as positive controls.

Results:

The three kinds of disc cells were able to form colonies, were negative for the expression of the surface markers CD14, CD34, CD45, CD71 and positive for CD44, CD73, CD105, CD151, expressed the stemness markers NANOG and POU5F1 and were able to differentiate toward osteogenic lineage as well as the MSCs. Differently from the MSCs, the disc cells showed no appreciable signs of differentiation towards adipogenic lineage. As expected, a better chondro-differentiation was observed in disc cells in comparison with MSCs in micromass culture. MMP1-3-13, VEGFA upregulation and TGFB downregulation were observed in disc cells and MSCs after IL-1β treatment. A slightly higher basal expression of TIMP1 and an higher basal expression of TIMP3 in MSCs in comparison with disc cells was observed. IL-6 was up-regulated by the pro-inflammatory treatment in all the cells. Basal levels of this cytokine were higher in MSCs in comparison with disc cells. There was a higher release of IL-1Ra in disc cells after IL-1β treatment, but the basal levels of this antagonist were significantly higher in ASCs in comparison with disc cells. Disc cells presented a behavior similar to MSCs in term of TNFα release. A low concentration of the anti-inflammatory IL-10 was detected in disc cells culture supernatant, whereas was undetected in MSCs before and after pro-inflammatory stimulus.

Conclusion:

The progenitors resident in the IVD showed very similar features to MSCs in term of clonogenic ability, immunophenotype, osteo-differentiation, stemness marker expression, trophic potential and response to a pro-inflammatory stimulus. Due to their preferential commitment towards the chondrogenic lineage, the in situ stimulation of these highly specialized progenitors could enhance a more physiological tissue repair and homeostasis maintenance.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577de

A109: Radiological, Histological, Morphological and Biochemical Comparison of Two Ovine Lumbar Intervertebral Disc Injury Models

Abstract

Introduction:

The ovine annular injury model of disc degeneration has been extensively used to evaluate potential therapeutic modalities for disc repair. However, there are limited studies describing the similar use of this species as a model for evaluating disc reconstitution following microdiscectomy. The goal of the present study was to compare the reproducibility and experimental outcomes of two microdiscectomy models induced in the lumbar spines of sheep using a standard drill bit or limited surgical excision of the annulus fibrosis (annulotomy).

Material and Methods:

Twelve adult ewes were subjected to pre-operative 3 T MRI followed by either lumbar intervertebral disc injury at two levels induced by a drill bit (n = 6) or by annulotomy (n = 6). Both surgical procedures were induced using a lateral retroperitoneal approach. The annulotomy method consisted of surgical removal of a 3 x 5 mm (approximately 200 mg) tissue from the outer annulus fibrosus (AF) to the nucleus pulposus (NP). The drill bit injury consisted of the lateral insertion of a rotating 3.5 mm diameter drill bit to a depth of 12 mm through the outer annulus fibrosus (AF) to the nucleus pulposus (NP) and parallel to the cartilage end plates. Necropsies were performed six months following microdiscectomies. Complete lumbar spines were removed and subjected to 9.4 T and 3 T MRI, radiographic imaging followed by sectioning through their vertebral bodies using a band saw. Individual lumbar discs were then processed for histological, gross morphological and biochemical analysis which included topographical assessment of proteoglycan content as sulphated glycosaminoglycans (SGAGs), collagen and DNA contents using standard procedures.

Results:

There was no evidence of disc degeneration on pre-operative MRI. Drill bit injured and annulotomy injured discs demonstrated significantly increased Pfirrmann degenerative scores relative to controls and pre-operative scores. There was no significant difference in Pfirrmann scores between the drill bit injured and the annulotomy induced microdiscectomies. Gross morphology injury scoring was significantly increased in annulotomy injured discs relative to drill bit injured discs. Annulotomy injured discs demonstrated significantly greater disc height loss than drill bit injured discs. Biochemical analysis of the site of disc injury from both microdiscectomy procedures revealed significantly reduced proteoglycan (as S-GAGs) content of the NP and AF relative to the corresponding uninjured controls. However, the annulotomy injured NP region had lower proteoglycan content than the corresponding drill bit injured region. Moreover, the collagen and DNA content of the drill-bit induced microdiscectomy AF region were also higher than for the annulotomy procedure. DNA levels represent a surrogate marker of capillary and blood cell infiltrations.

Conclusion:

These finding have demonstrated that both the 3.5 mm drill bit and annulotomy procedures are suitable ovine microdiscectomy models that could be used to evaluate novel modalities for disc repair. However, the annulotomy procedure results in a more substantial injury which is probably a more relevant model to the human clinical situation but will also demand more effective therapeutic agents to achieve repair than would be required for the drill bit microdiscectomy model.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577df

A110: Parvovirus B19 Infection in Intervertebral Disc

Abstract

Objective:

Virus are known as origin for various diseases. Vaccination against human papilloma virus is established for avoiding cervix carcinoma. Furthermore, Parvovirus B19 seems to play a role in appearance of cardiomyopathy and rheumatoid arthritis. Disc herniation is generally considered as a degenerative disease. But can we explain a disc herniation in youth and young adults to be degenerative? For evaluation the pathogenicity of parvovirus B19 related to the onset of disc herniation the present study was designed.

Methods:

Out of 47 patients with lumbar or cervical disc herniation that underwent spinal surgery, the disc herniation was tested for Parvovirus by PCR (cervical prolapse n = 16; lumbar prolapse n = 31). After surgical excision of the herniated disc the sample tissue was placed in RNA-later and stored at −20°C until the virological analysis was made. Initially samples of the patients’ blood serum were screened with ELISA for IgG antibodies. After the mechanical comminution of the disc material the nucleic acid was automatically extracted. Subsequently the viral nucleic acid was detected with quantitative polymerase chain reaction. Prion Protein DNA was added to the lysis buffer before the extraction as a combined extraction and inhibitioncontrol. The validity of the PCR tests was assured through positive controls and standards, which need to be in a certain target range.

Results:

In 21 samples we could detect positive PCR-results for Parvovirus, while the internal control is in the expected normal range. The serological testing of our patient collective showed a 76.6% IgG-positive result (n = 36), corresponding to the available data in literature for the spread of infection in the average population. Consequently 58.3% of serological positive patients and 44.9% of all patients showed an infection with Parvovirus B19 in herniated disc.

Conclusion:

The results of Parvovirus in herniated disc are surprising. This evidence suggests a possible correlation between the Parvovirus and the appearance of a disc herniation.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577dg

A111: Characterisation of the Annulus Fibrosus Mechanical Behaviour Requires a Specimen-Specific Approach

Abstract

Introduction:

Intervertebral disc degeneration treatments include nucleus augmentation. However failures during clinical trials have stopped widespread uptake. Development of standardized in-vitro testing methodologies to examine the biomechanical performance of nucleus replacement materials have shown high variability in the mechanical performance of specimens [1]. The aim of this study was to understand the causes of this variability with a computational approach.

Material and Methods:

Bovine tail specimens (N = 6) were used to develop a standardized in-vitro testing methodology. Specimen were sectioned to isolate the disc with 15 mm of bone each side and imaged with microCT; embedded in PMMA cement; and tested under static compression. Specimen-specific in-silico models of bovine tails specimens were produced: image-based models (ScanIP, Simpleware Ltd.) were developed with a standard protocol to create annulus and nucleus regions of the disc based on standard ratio of cross-sectional area. Material properties were assigned using linear elastic bone [2] and cement, fibre-reinforced annulus, and incompressible nucleus [3]. Computational specimens were loaded in compression replicating the experimental setup (Abaqus, Simulia). For both experimental and computational data, stiffness values and transition displacement were extracted using a tri-linear interpolation of load-displacement data. Three cases of fibre parameters in the annulus were compared: parameters derived from bovine-specific literature data [3], parameters calibrated [4] independently for each specimen, and parameters calibrated using a least square fit over the six specimens. Sensitivity studies were performed on the choice of standard values for the anatomy segmentation. Concordance correlations (R.3.1.1, R foundation for statistical computing) were performed to compare stiffness values and transition displacements for each specimen between each group of computational models.

Results:

Independent calibration of the fibre parameters led to mean relative errors on the predicted force below 15% for each specimen. Transition displacement values from the tri-linear fit exhibited high concordance between the three type of models (CCC > 0.99). Concordance between stiffness values computed using literature data and those independently calibrated was lower than between those calibrated as a group and values independently calibrated (respectively CCC of 0.85 and 0.95). A 50% variation of the cross sectional area ratio between nucleus and annulus led to a variation in the transition displacement or stiffness values of less than 8%.

Conclusion:

Using material properties derived in the literature from mechanical testing and average geometry measurements does not permit the reproduction of whole disc mechanical behaviour in static loading in other laboratory conditions. This reflects the wide variation in tissue preparation, specifically hydration levels, which translates into variation in tissue stiffness. Developing a specimen-specific image-based computational approach to reverse-engineer the mechanical behaviour of the fibres in the annulus fibrosis leads to material parameters that account for this tissue variation. This is necessary to be able to model pre-clinical testing conditions, a first step into enabling optimisation of this testing.

Acknowledgement

This project has been support by the Sina Trauma and Surgery Research Center, Tehran University of Medical Sciences (fund number: 93-02-38-25620).

References

[1] Schmidt et al, 2016, JBiomech 49 (6) 846-56.

[2] Mengoni et al, 2015 in [Uncertainty in Biology: A Computational Modeling Approach], Springer.

[3] Monaco et al, 2016, JMorphology 277 244-51.

[4] Mengoni M., 2015, opti4Abq, http://dxdoi.org/10.5281/zenodo.16659.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577dh

A112: The Utilization of Pressure Mapping Sensors to Measure Intradiscal Pressure Distribution and Implant Footprints: Abilities and Pitfalls

Abstract

Introduction:

The pressure distribution inside the intervertebral disc as well as the footprints of fusion implants remain in the focus of current research. To our knowledge pressure mapping sensors have not been used to provide information about the pressure distribution inside the intervertebral disc. We like to present some of the major abilities and pitfalls utilizing these tools.

Materials and Methods:

We present a method using a pressure mapping sensor (Model 5033 I-Scan; Tekscan, Boston, MA, USA) in a robot-based in-vitro testing setup with a follower load of 350 N.We used six human specimens (L2–L5). Five groups were tested: 1st intact; 2nd intact & 350 N; 3 rd pressure sensor & 350 N; 4th conventional fusion implant & 350 N; 5th expandable, prototype fusion implant & 350 N. The first and second group were used to define the “intact” status. For the third group a lateral, horizontal incision of the L3-L4 intervertebral disc close to the endplate of L3 was made and the pressure sensor pulled through the disc from one side to the other. The fourth and the fifth group consisted of an LLIF procedure with a conventional and a prototype implant with the pressure sensor between implant and endplate of L3. Both implants were covered with a 0.5 mm thick rubber pad to protect the pressure sensor from the spikes of the implants. The calibration of the pressure sensor was performed with a two-point calibration (100N/400 N) according to the manufacturer’s recommendation. The range was based on intradiscal pressure values from the literature.

Results:

If ROM of the second group is set to 100%, the horizontal incision through the disc resulted in a median ROM of 98% for EF, 146% for AR and 139% for LB. Although the intervertebral disc was completely cut, it showed excellent equalization of the pressure conducted by the movement of the spine. Only at the end points of each movement high pressure peaks could be observed. For EF these were at the ventral respectively dorsal edge of the intervertebral disc. AR and LB exhibited pressure peaks at the dorsolateral edge of the intervertebral disc. Unfortunately the pressure applied by the implants of the 4th and 5th group exceeded the upper calibration limit. Therefore only contact areas could be observed reliably but the detection of the different footprints succeeded well. Due to high sheer forces during insertion of the implants only 3 sensors of the 4th and 2 sensors of the 5th group remained reasonably intact.

Conclusion:

The insertion of the pressure sensor with a transdiscal incision destabilized the motion segment in AR and LB. In EF it remained stable. The pressure peaks in the intact scenario were located at the dorsolateral edge of the intervertebral disc. This location matched the clinical experience of dorsolateral disc protrusion and prolaps. We recommend two different sensor calibrations for intact and implant scenario, as the loads vary highly. The pressure mapping sensor allows excellent detection of footprint and contact area dynamically throughout biomechanical testing.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577di

Spine Infections 1
A113: Improvement in Frankel Scale in Caries Spine Patients with Frankel Scale “A” Undergone Anterior Decompression and Cage with Autologous Bone Graft after a 5 Years Follow up

Abstract

Introduction:

Spinal tuberculous infection is the most common and dangerous form of skeletal tuberculosis. It constitutes 1/3 to 1/2 of all bone and joint tuberculosis. It is a result of hematogenous dissemination from primary focus in the lungs, lymph nodes, etc . According to the current estimates of the WHO, tuberculosis now kills 3 million people a year worldwide. Therefore, early diagnosis and management of spinal TB has special importance in preventing serious complications.

Materials and Methods:

It is a prospective case series study. 419 patients either through OPD or Emergency Department with Frankel Scale “A” from 2003 to 2011 were included. After taking proper history, examination, investigations and proper consent, all the patients underwent anterior decompression and locally made cage with autologous bone graft. Data was initially entered on pre formed Proforma and then using SPSS 17.0. After surgery, patients were given brace for 6 months and were followed at 6 weeks, 6 months, and then yearly upto 5 years to assess improvement in Frankel scale. The objective of the study was to determine improvement in Frankel Scale after anterior decompression and stabilization with locally made stand alone cage and bone graft in caries spine.

Result:

419 patients presented with Frankel Scale “A” between 2003 to 2011. 21(5.01%) patients were lost to follow up. Out of remaining 398, 213(53.52%) were male and 185(46.48%) were females. 123(30.90%) were below 15 years, 167(41.96%) were between 16-40 years and 108 (27.14%) were above 40 years. All patients having Frankel Scale “A”. After 1 year only 19 (4.77%) patients showed Frankel Scale “E” While after 3 and 5 years 167(41.96%) and 189(47.49%) patients show Frankel scale “E”.90(22.61%) patients showed Frankel Scale “D”,67(16.83%) showed “C”, 24 (6.03%) showed “B” while 28(7.04%) patients showed no improvement after 5 years follow up.

Conclusion:

Early diagnosis and early intervention gives excellent results. However the patients with Frankel Scale “A” with delayed presentation after anterior decompression, stabilization with cage and bone graft results in significant improvement of Frankel Scale. Moreover there is no need for added instrumentation.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577dj

A114: The In Vitro and In Vivo Effects of Vancomycin on Osteogenesis in Lumbar Spine Surgery

Abstract

Introduction:

Surgical site infections (SSI) represent a major complication in lumbar spine surgery. While a number of studies have been conducted to review the effect of vancomycin on surgical site infections, a minimal amount have examined its impact on local bone cells at the cellular level. Recent in vitro studies have suggested that vancomycin has an inhibitory effect on osteoblast proliferation and differentiation which may effect fusion rates. The primary purpose of this study was to retrospectively examine our institution’s overall revision rate for pseudarthrosis and infection before and after the routine use of vancomycin powder for lumbar fusions and correlate in vitro data of the effects of vancomycin on osteoblasts at a concentration based on surgical drain samples.

Material and Methods:

Drain samples were collected and vancomycin levels were analyzed from 37 patients following spinal fusion procedures where powdered vancomycin was placed inside the surgical site for postoperative day 0, 1, 2, and 3. A human osteoblast (HOB) cell line was used to model osteoblasts in vitro. Cell medium was changed to include vancomycin at a concentration based on drain level results. After exposure of the human osteoblasts to vancomycin, cellular metabolic (alamar blue) and osteogenic activity (alkaline phosphatase) was subsequently evaluated. A retrospective chart review of 453 patients including all patients undergoing lumbar fusions with at least 2 years of clinical follow up from 1/1/2007 - 12/31/2009 (pre-vancomycin group) and comparing them to all patients between 1/1/2012 - 12/31/2013 (vancomycin group). I&D codes of CPT: 22010, 22015, 10180 were used to determine which patients had SSI. Data reviewed included number of levels fused, use of bone morphogenetic protein (BMP), and use of inter-body grafts.

Results:

HOBs exposed to vancomycin concentrations of 1250 ng/ul (POD 0) showed significantly lower alkaline phosphatase activity compared to those exposed to 0, 245(POD 3), 285(POD2), and 500(POD1) ng/ul (P = .017, P = .004, P < .001, and P < .001 respectively). Interestingly, there was a significant increase in ALP activity comparing HOBs exposed to vancomycin concentrations of 285 ng/ul compared to 0 ng/ul (P = .035), whereas there was no significant difference in metabolic activity measured between the cells exposed to 0, 245, 285, 500, and 1250 ng/ul of vancomycin (oneway ANOVA, P = .19). Overall revision for psedarthrosis and infection respectively were: 8/221 (3.6%) and 4/221 (1.8%) in the Vancomycin group and 11/232 (4.7%) and 9/232 (3.9%) in the pre-vancomycin group, with a trend towards significance. There was a significant difference in the use of interbody grafts (P = .016) and BMP use in the pre-vancomycin group (P = .001); however, no significant difference was noted in the number of levels fused.

Conclusion:

The results of the in vitro data suggest a threshold value of vancomycin that favors osteogenesis, corroborating the in vivo data that vancomycin did not significantly alter our fusion rates despite significantly less use of interbody grafts and BMP use. Further in vivo and in vitro studies are necessary to fully elucidate the optimal dose of vancomycin and its role in the maturation of a fusion.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577dk

A115: Hematogenous Spondylitis caused by Methicillin-resistant Staphylococcus Aureus Incidence, Risk Factors, Management and Outcomes

Abstract

Introduction:

The incidence of hematogenous spondylodiscitis is increasing. This may due to a combined effect between an increase in susceptible populations and an improved accuracy in diagnosis. Staph. aureus is the organism accounting for up to 80% of spondylodiscitis cases. MRSA- spondylodiscitis is similarly increasing and represents 10-30% of all Staph. aureus isolates.

Patients and Methods:

Retrospective analysis of the prospectively collected data of all patients with spinal infection between Jan. 2005 and Dec. 2015. The study revealed 600 patients with hematogenous spinal infections after exclusion of the cases with postoperative, wound infections and the cases treated for infection before this period. A causative organism could be identified from the site of infection in 405 patients (67.5%). Staph aureus was isolated in 171 patients of them. In this substudy we collected all cases of MRSA-spondylodiscitis and analysed the demographic, clinical, radiological and laboratory data as well as the outcomes of management in those patients.

Results:

This study identified 30 MRSA-patients of a total of 171 hematogenous Staph. aureus-infections (17.5%). There were 8 females and 22 males with mean age of 65 ± 10.9 years (37-81) and 28 (93.3%) were older than 50 years. In that age group, 70.3% of the patients had ASA- Score class III and IV and 33 patients (63.3%) were obese or overweight. The most common comorbidities were cardiac (22 patients), DM (18), renal insuffiecncy (17), peripheral vascular insuffiecncy (16). In 26 cases another site of infection outside the spine was diagnosed at admission. At the time of presentation, 19 patients (63.3%) had received antibiotic treatment for 24.36 days on average (±17.75, range 2-60 days). The pre-surgical interval ranged between 5-90 days (mean 33.14 ± 23.61). At admission neurological deficit was present in 22 patients (73.3%), fever in 20 (an organism could be isolated from blood culture in 17 of them) and sepsis in 10 patients. The lumbar spine was affected in 17 patients (56.7%). In most cases (26 = 80%) one segment was affected. Multifocal (non-contiguous) infection was found in 5 individuals. In 27 patients, epidural abscess was found and in 5 psoas abscess was present. The preoperative inflammatory parameters revealed mean CRP of 161.3 ± 105.84, WBC of 12.11 ± 6.15, ESR of 104.8 ± 23.37. In 3 patients (10%), more than one organism could be isolated (mixed infection). Surgical management was proceeded in 29 patients; combined ventro-dorsal approach was necessary in 26 of them. In three patients, recurrence of infection has been detected and treated surgically (10%). Four patients died with septic shock (one preoperatively), 2 patients with cardiac infarction, one with renal failure and one with respiratory failure (in-hospital mortality of 26.7%). The neurological improvement rate of at least one ASIA-grade reached 78%. Postoperative antibiotic therapy for more than 12 weeks was given in 17 patients (mean period of 70.6 ± 36.36 days). The most commonly used antibiotic was Vancomycin in 19 patients and in 11 patients a combination of antibiotics was necessary.

Conclusion:

In spite ofadvances in diagnosis and management strategies of spinal infections, the haematogenous spondylodiscitis by MRSA is still a devastating condition. It is associated with significant morbidity and mortality. The type and duration of antibiotic therapy should be organism based, but all patients with previoushospital admission who have been diagnosed with spondylodiscitis without a positive culture should receive an antimicrobial regimen that provides cover for MRSA.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577dl

A116: Perioperative Invasive Vascular Catheterization Associated with Increased Risk of Postoperative Infection in Lumbar Spine Surgery: An Analysis of 65,158 Patient Records

Abstract

Introduction:

Infection is a risk inherent to lumbar spine surgery, with overall postoperative infection rates of 1.9-2.1% despite advancements in aseptic technique, prophylaxis, and careful patient selection. Patients with postoperative infection are more likely to die, require revision surgeries, experience pseudarthrosis, osteomyelitis, failure of the primary intervention, and worsening pain and disability. Placement of arterial and central venous catheters (CVCs) in the perioperative setting is routine practice, particularly when caring for patients at risk for hemodynamic instability. Although central line associated infections have been studied extensively, no studies have assessed the risk of postoperative infection with perioperative invasive vascular catheter placement in lumbar spine surgery.

Materials and Methods:

In this retrospective cohort study, data was collected for patients undergoing lumbar spine surgery between January 2007 and December 2015 with records in the nationwide Humana private insurance database. Patients receiving single- and multi-level fusion, laminectomy, and discectomy were followed retrospectively for two months for perioperative infection complications, including wound infection, osteomyelitis, and subsequent incision and drainage. We then determined how a variety of risk factors, including central venous catheterization and arterial-line placement, modified the risk of postoperative infection.

Results:

Analysis of 65,158 patient records demonstrated an overall infection rate of 4.7% (2,925/65,158) within 2 months. Only 2.4% (1,526) of patients received a new central venous catheter on the day of their spine surgery, while 15.8% (8,896) received an arterial catheter. Patients receiving a new central venous catheter on the day of their spine surgery were more likely to experience infection (RR 3.0, 95% CI: 2.4-3.7), osteomyelitis (RR 6.6, 95% CI: 3.8-11.3), and undergo an incision and drainage (RR 3.0, 95% CI: 2.0-4.5) within 2 weeks post-op. Likewise, patients receiving a new arterial line on the day of their spine surgery were more likely to experience infection (RR 2.3, 95% CI: 2.0-2.6), osteomyelitis (RR 3.2, 95% CI: 2.2-4.8), and undergo an incision and drainage (RR 2.0, 95% CI: 1.6-2.6) within 2 weeks post-op. These trends were consistent through the 2-month follow-up period, with risk of all outcome measures increasing over that time period.

Conclusions:

In our study both perioperative CVCs and arterial lines significantly increased the risk of post-operative infections. Because the overall infection rate in lumbar spine surgery is relatively high (4.7% in our study), only 13 patients need to be given a new CVC with lumbar spine surgery in order for one to experience infection (NNH = 13). A causal pathophysiologic explanation for the observed risks is that bacteremia induced by placement of invasive vascular catheters leads to hematogenous seeding of surgical sites. Additionally, patients in need of invasive vascular catheterization may be inherently more ill, and therefore less likely to mount a robust systemic immune response to combat infection. Our data suggest that in patients requiring invasive catheterization, surgeons should consider the marginal risks and benefits of lumbar spine surgery more carefully.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577dm

A117: One Stage Surgical Treatment of Infected Lumbar Total Disc Arthroplasty with Cutaneous Abdominal Fistulas: Report of 3 Cases

Abstract

Introduction:

Infection following lumbar total disc arthroplasty (TDA) is a rare, albeit serious event. Treatment of this condition is challenging due to a) possible involvement of major retroperitoneal vessels, b) tendency for an infection with low pathogenic microbes that are difficult to verify, c) accompanying prevertebral abscesses, and d) little experience of surgeons in handling this rare complication. Although mentioned in each review, today only two case reports about this serious complication after lumbar TDA are available in the literature. Hence, to the best of our knowledge this is the largest case series about infected lumbar TDA published so far.

Material and Methods:

Three patients (2 male, 1 female, average age: 41 years) with 5 infected lumbar disc prostheses (3 x L4/5, 2x L5/S1). All cases were late infections occurring between 9 months and 6 years following index surgery. Presenting symptoms included abdominal and lumbar back pain (VAS back pain: 8.3, VAS leg pain: 4.3) and cutaneous abdominal fistula. Leukocyte counts and CRP were elevated significantly. Psoatic abscesses were seen on CT- and MRI scans in all 3 cases. Two patients had unsuccessful repeated local abdominal revisions (6 and 8 times).

Results:

Treatment involved a one stage, two-step revision surgery with posterior stabilization and fusion using pedicle screws. Additionally, an anterior (2x) or a lateral transpsoas approach (1x) with TDA removal and fistula excision followed by stabilisation using titanium cages packed with autologous bone graft was performed. Surgical treatment was accompanied by iv. antibiotic therapy for 3 months. Average OR time was 5 hours (296 Min). Although in average 3 lesions of either the vena cava, the left iliac vein or the ascending iliolumbar vein occurred during anterior surgery average blood loss was only 1.6 l. No postoperative complications occurred and all 3 patients made an uneventful recovery. Serum parameters subsequently returned to normal values. After 12 months follow-up all patients were clinically satisfied (VAS back pain: 0.6, VAS leg pain: 0). Fusion was accomplished in all cases as documented by serial X-rays and CT scans.

Conclusion:

One stage implant removal and instrumented fusion is an effective and safe surgical treatment for patients with infected lumbar TDA. TDA removal is possible using either anterior or lateral transpsoas approaches. Individual case planning is mandatory to achieve satisfactory results. However, vascular lesions are common and have to be anticipated during the planning and preparation to make this complex revision surgery safe.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577dn

A118: Wound Infection after a Spinal Surgery Has Got a Negative Influence on the Patients’ Subjective Long Term Treatment Outcome

Abstract

Introduction:

Limited data has been published about the long term effect of a surgical complication. One of the major complications after a spine surgery is the wound infection (surgical site infection, SSI), but the effect of this compliaction on the long term treatment outcome of the index surgery is not known. The aim of the study was to explore the effect of SSIs on the objective and subjective long term outcome in a prospective cohort of lumbar degenerative surgeries.

Materials and Methods:

One thousand thirty (N = 1030) patients were recruited into the study. Patients underwent single- or two-level microdiscectomy, decompression or instrumented fusion from open posterior approach. Revision surgeries were excluded. A questionnare booklet was filled out before and two years after the index surgery by the subjects. SSIs were diagnosed and treated according to the CDC guidelines. Treatment outcome was determined in terms of the change in Oswestry Disability Index (ODI), Core Outcome Measurement Index (COMI) and pain (VAS). Subjective global treatment outcome (GTO) was also reported by the patients. Comparisons were made applying Chi2-test and t-tests, where P < .05 was considered significant.

Results:

Prevalence of SSI was 3.9%. A significant difference in score-change of pain and disability between patients with “good” and “poor” GTO (p(ODI) < 0.001, p(COMI) < 0.001, p(VAS) < 0.001) was observed. There was no significant difference in the results of the patient reported outcome measures (ODI, COMI, VAS) in case of an SSI (P > .05) two years after the surgery. On the other hand, patients suffered the complication reported a signifcantly worse GTO two years after the surgery compared to the patients who did not have any wound infection (“poor” outcome in the SSI group was 24% compared to 12% in the non-SSI group, P = .017).

Conclusions:

Guideline-based diagnosis and management of an SSI after a spine surgery can help to achieve an optimal physical status long term. On the other hand, even in case of a careful treatement process, the appearance of a major complication can signficiantly influence the sunjective patient reported treatment outcome which means an increased risk for patient’s dissatisfection and its psychosoical consequences. Based on our findings, the deeper analysis of the psychological consequences of surgical complications as well as the development of possible mitigation startegies are advised.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577do

Minimally Invasive Spine Surgery 1
A119: Minimally Invasive Resection of Ventral and Ventrolateral Intradural Extramedullary Spinal Lesions: Clinical Outcomes and the Addition of Image Merge Technique

Abstract

Introduction:

Posterior translaminar approaches for resection of ventral and ventrolaterally placed intradural extramedullary lesions is challenging. Reports using these approaches for ventral lesions show a high neurological complication rate, likely due to spinal cord manipulation. Minimally access surgery (MAS) with image guidance minimizes soft tissue morbidity, and may potentially facilitate tumor resection and lower complication rates for tumors ventral to the spinal cord. We present our results of MAS image guided surgery for intradural ventral and ventrolateral lesions resected through a paramedian oblique tubular MAS approach.

Methods:

Retrospective review of clinical, radiological and surgical records of patients operated for intradural mass lesions with MAS technique from 2004 to 2016. Preoperative status, lesion location, surgical technique (MAS vs IMTAR) and follow-up surgical results and complications were documented according to the type of MAS technique (image merged vs classic image guided).

Results:

54 patients operated using tubular techniques for intradural lesions, there were 12 ventrally located lesions. Mean age was 57 years (range 23-92), 6 males and 6 females. There were 7 meningiomas, 4 schwannomas, and 1 arachnoid cyst. 6 patients presented with myelopathy, 4 with radiculopathy, 2 dorsal pain. Surgery was performed with fluoroscopic guided tubular MAS technique in 7 cases while 5 patients were treated using the IMTAR technique (Maduri et al 2016), both using a posterolateral oblique transmuscular trajectory. Bone removal was tailored to resection needs. Mean blood loss was 253 mL. Miniextracavitary costotrasversectomy was necessary in 3 patients, complete facetectomy in 3 patients and complete pediculectomy in 1 patient. Mean hospital stay was 7.8 days (3-26). Postoperatively, there were no neurological complication and no CSF fistula. 1 patient had superficial wound infection treated with antibiotics. 2 patients with Schwannoma underwent deliberate nerve root sacrifice with expected postoperative radicular sensory loss. GRT was achieved in 13 patients. Mean FU was 24.8 months (1-60), only 1 patient presents myelopathy, 3 patients with dysesthesia controlled with medical treatment. Axial pain is present in 1 patient operated for a C2-C3 meningioma with no radiological signs of instability.

Conclusions:

Translaminar approach for ventral intradural spinal tumors has been reported to have a 41.6% overall complication rate (25% of postoperative neurological deficit) and 1.5% of mortality (Mehta et al, 2013). MAS facilitates surgical access to ventral and ventrolateral tumors with almost a 180° range of access. Furthermore, implementation of intraoperative image guidance allows customization of surgical trajectory, bone resection and tumor removal thus reducing the risk of neurological complication. In the present series the rate of overall complication and neurological aggravation is low despite the ventral location of the lesions. Although our experience with these techniques is small, we believe that for ventral and ventrally located spinal tumor, the use of MAS image guided tubular techniques optimizes tumor access and may facilitate a reduction in neurological morbidity. Further experience is needed to confirm this.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577dp

A120: Old Dogs, New Tricks: What Motivates Experienced Spine Surgeons to Try Minimally Invasive Surgery?

Abstract

Introduction:

The aim of this study was to explore the motivations of spine surgeons who have sought to learn new technical skills through a qualitative analysis of the self-identified motivational factors that purportedly shaped their decision to learn a new technique. Embarking on a learning pathway to gain competence in a new procedural skill is a major undertaking for experienced surgeons. Their expertise in the surgical procedures they routinely use has been obtained through years of practice. To step outside their comfort zone and risk harming their patients while they gain expertise in a new procedure requires strong motivation. To my knowledge, a qualitative analysis of this process has not been done with specific reference to spinal surgery. If we are able to identify salient mediating factors related to changing surgical techniques amongst experienced surgeons, then we may be able to enhance the design of future educational interventions in spinal surgical training.

Materials and Methods:

The research method was in-depth interviews with spine surgeons who have more than ten years of experience and had made a deliberate choice to adopt a new surgical technique in their practice in the last five years. They were recruited by direct invitation to view an information and consent document in a Dropbox file. Seven surgeons agreed to participate in the study.

Results:

The surgeons interviewed were all male, four orthopaedic surgeons and three neurosurgeons. Their age range was 44 to 63 years and they had been in specialist practice for between 12 and 30 years. All of them were self-employed, some were in private practice alone but most were working in the public and private health system. The interview transcripts were analysed using direct content analysis with codes derived from existing literature on change of practice motivation.All seven of the surgeons interviewed identified the desire to improve patient outcomes and avoid complications as being the two major motivators for adopting a new technique. Other common factors included having more treatment options, staying up to date and trying something new. Some of them mentioned financial gain and competing with colleagues. They were all asked about techniques they had adopted and techniques they had tried but not taken up. Minimally invasive spinal surgery was identified by all as likely to improve patient outcomes but only two continued with the technique and five decided not to adopt. The other common technique was corrective surgery for degenerative deformity. This apparent dichotomy between seeking a new technique to improve patient outcomes or avoiding having to learn a new technique due to concern over possible complications was a recurring theme during the interviews.

Conclusions:

The experienced spine surgeons in this study were motivated to adopt a new technique after identifying areas in their practice where patient outcomes could clearly be improved or complications avoided. The process of learning the new technique involved embarking on a learning curve with its potential difficulties, which for some was accepted but for others was a deterrent.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577dq

A121: A Single-Incision, Oblique Retroperitoneal Approach for Lumbar Interbody Fusion from L1 to S1 in Adult Spinal Deformity

Abstract

Introduction:

Retroperitoneal lumbar oblique corridor was defined as the left lateral border of the aorta (or iliac artery) and the anterior medial border of the psoas. The L5/S1 corridor of access was defined transversely from the midsagittal line of the inferior end plate of L5 to the medial border of the left common iliac vessel and vertically to the first vascular structure crossing the midline. This provides a slightly oblique trajectory to the intervertebral disc spaces of L1 to L5, with a separate Pfannenstiel approach required for access to the L5/S1 intervertebral disc space. Consequently, separate incision and position change is needed to perform L5/S1 oblique interbody fusion. To perform oblique lateral interbody fusion from L1 to S1 without separate incision and position change, the authors placed the patient in a 45° right oblique decubitus position. This modified oblique retroperitoneal approach allows extending access to the L5/S1 intervertebral disc without separate incision and position change. In this study, we illustrated a single-incision oblique retroperitoneal approach for lumbar interbody fusion from L1 to S1 in adult spinal deformity and evaluate the radiographical findings and clinical outcomes of patients treated using this technique.

Material and Methods:

This study included 15 patients scheduled to undergo anterior and posterior long level fusion for lumbar degenerative kyphosis or degenerative lumbar scoliosis. Data collected included blood loss, operative time, incision size, perioperative complications. Pre- and postoperative radiographic parameters and clinical outcome measures were assessed. Mean follow-up time was 22.1 months.

Results:

The mean Blood loss was 107.4 ml,12.4 ml and 87.6 ml with in 5 levels(8 cases), 4 levels(6 cases) and 3 levels(1case), The mean operative time was 116 minutes, 97minutes and 82 minute the patients with in 5 levels(8 cases), 4 levels(6 cases) and 3 levels(1case). The mean incision sizes were 14.63 cm, 13.82 cm and 12.5 cm in the patients with 5 levels, 4 levels and 3 levels. The mean preoperative sagittal vertical axis was +17.12 cm and postoperative sagittal vertical axis was +2.11 cm. The preoperative lumbar lordosis was 3.28°and the postoperative lumbar lordosis was 48.08°. The mean pelvic incidence was 51.64°. The mean correction angle was 59°. There was no injury to the iliac artery or vein, but there were complaints of groin and medial thigh pain in 3 cases, however the pain disappeared at 3 months postoperatively. There was no retroperitoneal hematoma or herniation. In 2 cases, the peritoneum was torn during the surgery and was sutured immediately with no complication.

Conclusion:

The outcomes from our study demonstrate that this oblique retroperitoneal approach is a very safe, allowing reproducible access from L1 to S1 for lumbar interbody fusion in adult spinal deformity. It is associated with a short operative time, minimal blood loss. Furthermore, this approach may have a number of theoretical advantages to traditional techniques. It may facilitate greater sagittal deformity correction with placement of lordotic anterior interbody cages, and the need for a three-column osteotomy in the setting of significant deformity may be avoided.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577dr

A122: Treatment of the Fractional Curve of Adult Scoliosis with Circumferential Minimally Invasive Surgery (cMIS) versus Traditional, Open Surgery: An Analysis of Surgical Outcomes

Abstract

Introduction:

The fractional curve of adult scoliosis can cause significant radiculopathy. We sought to evaluate the outcomes of patients whose fractional curves were treated with either cMIS or open techniques.

Material and Methods:

A multicenter retrospective review of an adult spinal deformity database of MIS and open surgically treated patients, with the following inclusion criteria: age >18 years with fractional curves >10°, ≥3 levels of instrumentation, and one of the following: coronal Cobb angle (CCA) > 20°, PI-LL > 10°, PT > 20°, SVA > 5 cm.

Results:

420 patients met inclusion criteria for the database, of those, 165 had complete 2 year data. 118 patients had their fractional curves treated, 79 open and 39 cMIS. The fractional curves were similar pre-op (17 cMIS, 19.6 open) and post-op (7 cMIS, 8.1 open), but open had more levels treated (12.1 vs 5.7). cMIS had greater reduction in VAS leg (6.4 to 1.8) than open (4.3 to 2.5). When propensity matched for levels treated (6.6 cMIS and 7.3 open), 40 patients had their fractional curves treated with either cMIS (n = 20) or with open (n = 20) surgery. Both groups had similar fractional curve correction (18° in both groups before surgery, 6.9° in cMIS and 8.5° in open after). cMIS patients had a smaller postoperative coronal Cobb angle (12.5° vs 24.3°) and lower EBL (809 cc vs 2299 cc). Open patients had a higher SVA change (−19.6 vs +13.2), more pelvic fixation (55% vs 15%), and more direct posterior decompressions (80% vs 22.2%). Both groups had similar pre-op leg pain (VAS leg 6.1 cMIS and 5.4 open) and similar postop leg (VAS leg 1.6 cMIS and 3.1 open). All cMIS patients had interbody grafts whereas 35% of open did. The cMIS and open patients had similar reduction in leg pain (change VAS Leg −4.4 vs −2.2). There was no significant difference in change of Cobb angle, PI-LL, LL, ODI or VAS Back.

Conclusion:

In the treatment of the fractional curve of adult scoliosis with magnitude greater than 10 degrees, patients treated with cMIS achieved similar reduction in leg pain compared to those treated in an open fashion, even though significantly fewer cMIS patients underwent direct decompression of the fractional curve nerve roots.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577ds

A123: Learning Curve for MISS Aspirants: A Retrospective Review from Five Years of Minimal Invasive Spine Surgeries

Abstract

Introduction:

There is an inherently difficult learning curve associated with minimal invasive surgical approaches to spinal decompression and fusion. Complication rates and learning curve are often associated with little information about their correlation.

Materials and Methods:

We did a retrospective review of 126 patients operated by the same surgeon during first five years of independently implementing MISS (Minimal Invasive Spine Surgeries). All surgeries were done by MED (Micro Endoscopic Discectomy) technique (later on also added with MISS fixations) between 2011 and 2016. All had disc herniation and/or lumbar stenosis at single or double level with or without instability and were followed up till date for clinical results, VAS (Visual Analogue Score) and complications. The indoor charts were also reviewed to compare intraoperative blood loss, operative time, hospital stay, and any other complications.

Results:

Average age was 44 ± 11 years and average operation time was 117 ± 54 minutes. The analysis of the operative time showed that the average surgical time decreased to less than 90 minutes after 30 surgeries. The operative time for MED was around one hour after 50 surgeries and MISS fixations were done in less than 3 hours. After 50 surgeries, the timing for single level discectomy and decompression was less than 60 minutes including bilateral decompression with unilateral approach. Hospital stay was around 3.06 ± 1.38 days which were uniformly same in all surgeries. Pre-operative VAS score was 8.6 ± 0.9 v/s 1.8 ± 1.3 (P < .05) in the post-operative period. Intra-operative and post-operative complications such as dural tear or root injury, postoperative hematoma, incomplete excision requiring revision and loosening of screw cap were found in initial 50 surgeries (11 versus 1 between first 50 and later cases respectively).

Conclusion:

MISS procedures for discectomies and spine fixations have shown early encouraging results. However, a spine surgeon needs to believe and stay persistent while implementing MISS surgeries inspite of excellent clinical hands on fellowships. As per our case series, first 30 surgeries should be restricted to MISS decompression and discectomy without getting stressed by difficulties. Next 20 cases can be combined with some MISS fixations and mastering the technique. After the first 50 cases, bilateral decompression with or without fixation and TLIF (Trans-Foraminal Lumbar Inter-body Fusion) can be considered.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577dt

A124: Efficiency of MISt (Minimally Invasive Spine Stabilization) for the Patient of Metastatic Spinal Tumor

Abstract

Introduction:

Metastatic spinal tumor is a frequent complication in cancer patients. Traditional aggressive surgical strategies for metastatic spinal tumors are associated with high morbidity and complication rates, which can limit their indication in patients with a limited life expectancy. Even as minimally invasive spine stabilization (MISt) gains popularity in Japan, effectiveness for the treatment of metastatic spinal tumors has yet to be established.

Methods:

The subjects comprised 37 cases that underwent surgery using the MISt technique against metastatic spinal tumors. The cases included 21 men and 16 women, with a mean age at surgery of 66 years old. The primary tumor was: breast cancer in10 cases, prostate cancer in 8 cases, lung cancer in 7 case, and another cancer in 12 cases. We checked operation time, blood loss, length of time taken until recovery, complications, and prediction of the prognosis using the Tokuhashi score, Tomita score and Katagiri score. The Frankel classification was used for paralysis. And we have evaluated instability of the spine using Spine Instability Neoplastic Score (SINS).

Results:

The mean operation time was 173 minutes (50-410 minutes). The mean blood loss was 123 g (10-810 g). The number of fusion areas was 5.8 vertebrae (3-24 vertebrae).The mean time taken until recovery was 3.7 days (1-14 days). The averageTokuhashi score was 8.9points, Tomita score was 5.3 points, Katagiri score was 3.6 points. SINS score was 9.9 points (indeterminate instability). No complications were reported during the procedure. PS was improved after surgery, and the number of Frankel E cases was 63%. Regarding paralysis, no improvement was observed.In addition, even the survival probability for the group with no paralysis was significantly longer.

Conclusions:

The benefits of the MISt technique against metastatic spinal tumor is 1) Few infections. 2) Less bleeding. 3) Early recovery. 4) No need to open the wound. 5) A more rapid initiation of postoperative adjuvant therapies. The results of this study revealed that the MISt for patients with metastatic spinal tumor, especially of thoracolumbar spine was safer and less invasive surgical management. It should be considered as palliative surgical strategy in patients with limited life expectancy, to limit morbidity and preserve quality of life.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577du

Novel Technologies 1
A125: Detethering of the C2 Nerve Root and Avoidance of Transection and Injury during C1 Screw Placement: A Cadaveric Feasibility Study

Abstract

Introduction:

Regional neurovascular structures must be avoided during invasive spine hardware placement. During C1 lateral mass screw placement, the C2 nerve root is put in harm’s way. Therefore, the current anatomical study was performed to identify techniques that might avoid such neural injury.

Materials and Methods:

On 10 cadaveric sides, dissection was carried down to the craniocervical junction. The C2 nerve root was identified and its distal branches traced out into the surrounding posterior cervical musculature. Once dissected, the nerve was displaced inferiorly away from the lateral mass of C1.

Results:

On all sides, the C2 nerve root could be easily detethered from surrounding tissues. On all sides, this allowed lateral mass screw placement without compression of the nerve.

Conclusions:

Based on our cadaveric study, the C2 nerve root can be detethered enough at the level of the posterior lateral mass of C1 to avoid its injury during screw placement into this area.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577dv

A126: Development of a New Assessment Tool for Cervical Myelopathy using a Virtual Reality Hand Tracking Sensor

Abstract

Introduction:

Myelopathy hand is a characteristic feature of cervical myelopathy. Since there are only a few scales to quantify the severity of cervical compressive myelopathy, there is a need to introduce a universal objective platform in outpatient settings. Virtual-Reality offers promise as a means of producing quantitative data regarding the function of the neural system in the hand. The Leap Motion Controller (LMC) is a small, USB Virtual-Reality motion tracking device that could be used for this purpose. The aim of this study was to assess the reliability and validity of the LMC in the 15-second hand grip-and-release (G-R) test, as compared against human inspection of an external digital camera recording. Moreover, to set a baseline measurement of the number of hand flexion-extension cycles and analyse the degree of motion in young healthy individuals, besides examining gender and dominant hand differences.

Materials and Methods:

Fifty healthy participants were asked to fully grip-and-release their dominant hand as rapidly as possible for three tests, each separated by a 10-minute rest, while wearing a non-metal wrist splint. The first two tests lasted for 15 seconds, and a digital camera was used to film the anterolateral side of the hand on the first test. The third test lasted for a maximum of three minutes or until subjects fatigued. Three assessors counted the frequency of G-R cycles, of the recorded videos, independently and in a blinded fashion. One assessor counted the frequency of grip-and-release cycles as well as the number of motions (magnitude of motion) from the data output of the LMC. The average mean frequency of the three video observers was compared with that measured by LMC using the Bland-Altman method. Test-retest reliability was examined by comparing the two 15-second tests.

Results:

The mean number of G-R cycles recorded in each 15-second test was: 47.8 ± 6.4 (test 1, video observer); 47.7 ± 6.5 (test 1, LMC); and 50.2 ± 6.5 (test 2, LMC). Bland Altman indicated a bias of 0.15 cycles (95%CI = 0.10-0.20), with upper and lower limits of agreement −1.16 and 1.46 cycles, respectively. The ICC showed high inter-rater agreement (ICC = 0.998, 95%CI = 0.997-0.999, P < .01). The coefficient of repeatability for the number of cycles was ±5.393, with a mean bias of 3.63. Over 3 minutes, the frequency of cycles (per 10-second interval) decreased, as did the magnitude of motion. However, the decline in frequency preceded that of motion’s magnitude. Participants reached fatigue from 59.38 seconds; 43 participants were able to complete the 3-minute test. There were no statistically significant differences according to gender or dominant hand at most time intervals (P > .05).

Conclusions:

LMC appears to be valid and reliable in the 15-second grip-and-release test. This serves as a first step toward the development of a universal objective platform for the assessment of cervical myelopathy. Further assessment is warranted to gauge benchmark values in a wider range of healthy individuals and in cervical myelopathy patients. Assessing the LMC as a diagnostic tool in the clinical setting is also necessary.

Keywords: Cervical Myelopathy, Virtual Reality, Grip and release test, Reliability, Validity
Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577dw

A127: A Proinflammatory and Degenerative Intervertebral Disc Organ Culture Model to Investigate Novel Anti-inflammatory Treatment Approaches for Degenerative Disc Disease

Abstract

Introduction:

Degeneration of the intervertebral disc (IVD) is considered to be a major reason for low back pain. Proinflammatory cytokines, such as tumor necrosis factor α (TNF-α), were shown to be highly expressed in human degenerated IVD, causing a breakdown of extracellular matrix components by stimulation of matrix degrading enzymes. Therefore, therapies that inhibit the expression of proinflammatory cytokines may be a promising therapeutic approach to consider, aiming to reduce inflammation and maintain the IVDs extracellular matrix. However, no clinically relevant in vitro systems to test new anti-inflammatory therapeutics are available to date. The aim of the study was to design and evaluate a proinflammatory and degenerative organ culture model to simulate the early onset of degenerative disc disease (DDD).

Material and Methods:

Bovine IVDs with endplates were harvested and cultured with or without an intradiscal injection of TNF-α (100 ng TNF-α / IVD) for 4 days. IVDs were cultured within a bioreactor system under 2 different loading and medium conditions: (1) physiological loading (0.02-0.2 MPa; 0.2 Hz; 2h/day, 3 days) and high glucose (4.5 g/L) medium (Phy), or (2) degenerative loading (0.32-0.5 MPa; 5 Hz; 2h/day, 3 days) and low glucose (2 g/L) medium (Deg). IVDs were cultured free swelling between dynamic loading cycles. After the first dynamic loading cycle on day 1, TNF-α was injected into the disc nucleus pulposus (NP) tissue. Disc height was recorded daily after load and free swelling (FS) recovery. Conditioned medium was collected for nitric oxide (NO) and Glycosaminoglycan (GAG) analysis. After 4 days, NP and annulus fibrosus (AF) tissue were harvested and gene expression was analyzed using real-time PCR. GAG/DNA and Hydroxy-proline (OHP)/DNA content of the disc tissue were assessed. One-way ANOVA or Kruskal-Wallis tests were used to determine statistical significance.

Results:

Degenerative dynamic loading caused significantly higher disc height loss (~20%) compared to physiological dynamic loading (~10%). Intradiscal injection of TNF-α did not further induce disc height loss after loading. TNF-α combined with Deg condition up-regulated NO release from IVD (P < .01 Phy vs Deg+TNF-α). TNF-α injection also enhanced GAG release in Phy group (P < .05). Gene expression analysis demonstrated a decrease of type I collagen (COL1) in AF tissue, caused by Deg condition or TNF-α injection (P < .05). TNF-α injection combined with Deg condition induced an up-regulation of interleukin-6 (IL6) and matrix metalloproteinase 1 (MMP1) in NP tissue, as well as increased interleukin-1β (IL1B) gene expression in AF tissue (P < .05).

Conclusion:

This degenerative and inflammatory model is capable to induce catabolism on organ cultured IVDs indicated by a significant upregulation of catabolic and inflammatory gene expression markers in disc tissue, together with enhanced NO release. The early onset of DDD can be simulated and novel anti-inflammatory treatment approaches can be investigated under relevant conditions by utilizing this model. Further research will aim to analyze the biologic and biomechanical response of selective cytokine inhibitors on organ cultured IVDs as alternative therapies for DDD.

Acknowledgements

Funded by the Foundation for the Promotion of Alternate and Complementary Methods to Reduce Animal Testing (SET). Zhiyu Zhou was funded by China Scholarship Council and Sino-Swiss Science and Technology Cooperation.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577dx

A128: Comparative Analysis of Inflammatory Processes during Cervical and Lumbar Degenerative Disc Disease

Abstract

Purpose:

To investigate the occurrence of inflammatory processes in the sites of disc degeneration in the lumbar and cervical spine by a cytokine gene array and subsequent qPCR.

Materials and Methods:

Disc samples were obtained from 31 patients undergoing discectomy, 11 men and 20 women, with a mean age of 56 years. RNA was extracted by Trizol/Chloroform method and examined for 28 cytokines by a gene array (n = 6) and then followed up by standard qPCR for eight selected cytokines on all samples Samples had the following characteristics: site = 24x cervical and 7x lumbar; pathology = 11x disc herniation and 20x degenerative disease (all ≥ grade 3); level = 13x one level discectomy and 18x multilevel discectomy. For the patients that underwent multilevel discectomy, one sample was gathered. The nucleus pulposus (NP) and annulus fibrosus (AF) of the lumbar samples were seperately examined. Results were statistically analyzed by the two-sample Kolmogorov–Smirnov test with a significance level of P ≤ .05.

Results:

In both, cervical and lumbar discs, the interleukines IL-6 and IL-8 were found to be the overall highest expressed genes, whereas the expression of IL-1β, TNF-α and IL-15 (a disc cytokine that has been sparsely investigated up to now) was comparatively low. Interestingly, three previously unreported cytokines could be detected in cervical and lumbar disc tissue: the interferones INA1, IFNA8 and IFNB1. No statistically significant difference was found between cervical and lumbar samples, or between AF and NP samples for any of the investigated genes. Also, no correlation was found between gene expression and gender, age or the extent of the operation (single/multilevel).

Conclusions:

Our results show that no major differences exist in the inflammatory profile of cervical and lumbar degenerated discs, indicating that novel anti-inflammatory treatments currently under investigation may be applicable independent of the degeneration site. The high expression of IL-6 and IL-8 supports their described relevance in nociception and matrix degradation. Although IL-1β and TNF-α are well described to play a role in the pathogenesis of disc disease, their expression was comparatively low. Importantly, this study is the first to describe the expression of type I interferons (interferons alpha and beta) during disc degeneration, which can have both, proinflammatory and anti-inflammatory properties. Although their role in degenerative disc disease is currently unclear, they are often described to have immunomodulatory effects (e.g. in osteoarthritis) and may hence be a reactive attempt to inhibit inflammation in the disc. Further studies will be required to identify their disc-specific function as well as the role of IL-15, which has also been sparsely investigated thus far.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577dy

A129: Dysphagia in Standalone versus Conventional Anterior Cervical Discectomy

Abstract

Introduction:

Dysphagia is an extensively described complication of anterior cervical discectomy and fusion. It has been proposed that mechanical irritation, additional dissection or displacement of the esophagus by plate placement may contribute to a greater incidence of post-operative dysphagia. The aim of this study was to compare dysphagia symptoms and pain severity of standalone cage systems versus interbody devices in combination with an anterior plate.

Material and Methods:

A retrospective cohort study identified 377 consecutive patients (stand alone, n = 211; plate and cage, n = 166) meeting the study criteria between the years 2014 to 2015. Patient-specific characteristics and surgical characteristics and Numeric Pain Rating Scale (NRS) scores were collected preoperatively. Complication and readmission rates, the Dysphagia Disability Index (DDI), and NRS scores were collected at one year and two years post-operatively.

Results:

Both groups were similar with respect to age, gender, body mass index, smoking status, several comorbidities including the Charlson score, and pre-operative NRS scores (5.3 ± 2.1 versus 5.4 ± 1.9 in the stand alone and plate and cage groups, respectively). Patients in the stand along group were more likely to have a primary diagnosis of radiculopathy and less likely to have the diagnosis of myelopathy. They were more likely to have had prior cervical surgery (22.8% vs 13.3%; P = .02). Patients in the plate and cage group were more likely to have multiple levels of surgery (57.8% versus 34.6%; P < .01) and experienced a longer length of surgery (143 ± 51 minutes versus 108 ± 43 minutes; P < .01). Both groups experienced similar complication and readmission rates. The stand along group experienced a higher rate of symptomatic non-union with reoperation but this did not achieve statistical significance (9% versus 4%; P = .07). There was a significantly greater improvement in neck pain scores in the plate and cage group after one and two years post-surgery compared to the stand alone group (2.3 and 3.1 versus 1.6 and 1.5, respectively; P < .01). Post operative DDI scores were similar at 2 years post-surgery (9.4 ± 11.9 versus 9.5 ± 11.7).

Conclusion:

Chronic dysphagia scores are comparable between standalone cage systems and interbody grafts with plating. We observed a greater improvement in neck pain and a lower incidence of nonunion in the group that underwent interbody graft and plate placement at followup. Further research is needed in order to determine factors that may lead to a higher rate of non union for patients undergoing stand alone cage placement.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577dz

A130: Driving Reaction Time after Spinal Surgery: A Systematic Review

Abstract

Introduction:

The driving reaction time is defined as the amount of time, on the order of milliseconds or seconds, at which a driver can adequately react to a stimulus requiring them to brake emergently. Although, DRTs can vary depending on variables such as mental processing time, movement time, and device response time there are standard or safe ranges quoted in the literature. Thus, a standardized postoperative DRT might represent an objective indicator for when a patient can resume safe driving after spinal surgery. The objective of our study was to assess driving reaction times (DRTs) after spinal surgery, to establish a timeframe of when postoperative patient’s can safely resume driving.

Methods:

The MEDLINE and Google Scholar databases were analyzed according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analysis) statement for clinical studies investigating changes in DRTs following cervical and lumbar spinal surgery. Changes in DRTs and patients’ clinical presentation, pathology, anatomical level affected, number of spinal levels involved, type of intervention, pain level, and driving skills were assessed.

Results:

The literature search identified 12 studies addressing DRTs in postoperative patients; of those studies, 6 studies met the inclusion criteria. Amongst these 6 studies, 5 studies assessed changes in DRT after lumbar spine surgery and 2 studies after cervical spinal surgery. The spinal procedures included were: selective nerve root block (SNRB), anterior cervical discectomy and fusion (ACDF), and lumbar fusion and/or decompression. Overall, DRTs exhibited variable responses to spinal surgery dictated by the patients’ clinical presentation, spinal level involved, and the type of procedure performed.

Conclusions:

The evidence regarding patients’ ability to resume safe drive after spinal surgery is scarce. Normalization of DRT or returning to pre spinal intervention values represents a widely accepted indicator for safe driving with mixed statistically significance due to multiple confounding factors. Considering the type of spinal intervention, the pain level, opioid consumption, and cognitive function is unique to each case and will be more adequate reflection of when to safely resume driving

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577ea

Osteoporotic Fractures
A131: Bone Quality of Lumbar Spine Assessment Using Dual Emission X-ray Absorptiometry: A Potentially Misleading Results

Abstract

Introduction:

Diagnostic role of DEXA in bone quality assessment that is required to predict a low energy fracture and implant failure after spinal instrumentations is still questioned because of limited specificity. The aim of this study is to study the relationship between CT and DEXA to assess a potential bias in bone quality assessment.

Materials and Methods:

This is a cross-sectional study; twenty-five patients were selected for study who underwent a CT scan and DEXA of the lumbar spine. Using DEXA scan of a lumbar spine; BMD (g/cm2) was calculated for each vertebra of lumbar spine (L1-L4 inclusive). The CT scans were performed from the T12-L5 levels. The scans utilized a slice thickness was 0.5 mm, covering a scan area of 50 cm. The scan parameters included: tube voltage 120 kV, tube current 300 mA, auto mAs range 180-400; 1.0 sec/3.0mm/0.5x32, helical-pitch 21.0. Integrated software was utilized for calculations of bone density (Vitrea Version 5.2.497.5523) incorporating a window width/window level ratio of 2000/500. Measurements of bone radiodensity were obtained in HU from each vertebral body in the sagittal, axial and coronal planes from level L1 to L4 inclusively. Radiodensity was measured in two ways: a total vertebra body radiodensity including cortical bone and radiodensity of only a cancellous bone were obtained. Finally a mean value in HU was calculated for cancellous bone and a total vertebra body radiodensity. To study the impact of other structures on bone quality assessment using DEXA, a mean square and radiodensity calculated of right and left vertebra pedicles in frontal plane and a mean square and mean radiodensity calculated of right and left facet joints in axial plain were measured for each vertebra. General factorial regression analysis was applied to study relationships between CT and DEXA data.

Results:

The required measurements were taken from 100 lumbar vertebrae. The logistic regression analysis demonstrated a strong correlation between BMD measured by DEXA (dependent variable) and CT data (predictors). The estimated multiple correlation coefficient of estimated model accounts for 0.8093, r2 = 0.6550, P < .0001. The estimated parameters of regression model were: B0 = 0.4967149686, p,0,0001; B1 for cancellous bone = −0,0005116753, P = .4633, B2 for a product of facet joints radiodensity and mean square = 0,000003379, P < .0001; B3 for pedicle radiodensity on a frontal image = 0.0001253732, P = .2610; B4 for Pedicle mean square on frontal plane image = −0.0006727354, P = .08682; B5 for total vertebral body radiodensity = 0.0016395253, P = .0201. Beta coefficients for a product of facet joints radiodensity and total vertebral body radiodensity accounted for 0.6729 and 0.3037 respectively. Linear correlation analysis showed only a moderate correlation between a vertebra body and facet joints radiodensity r = 0.4854, P < .0001 (Pearson correlation).

Conclusion:

The results of bone quality assessment of spine column using DEXA can be strongly influenced by facet joints condition especially in case of degenerative changes. The provided by DEXA results of BMD are partly relevant to vertebral body bone quality assessment and irrelevant to the characteristics of bone in pedicles so that prognostic value of those results might be limited in relation to low energy vertebra fracture and implant stability forecasting.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577eb

A132: Vertebral Fracture Over the Metal Structure in Patients with Osteoporosis: Can We Prevent These Injuries?

Abstract

Introduction:

Compression fractures of the vertebrae at the junction with PSF are a serious problem. Most often these fractures occur in patients with osteoporosis. The experimental studies (Kebaish K.M. et al., 2013, Basankin I.V. et al, 2015) show the effectiveness of the preventive using of vertebroplasty for preventing fracture of the overlying vertebra above the pedicle screw system. The purpose of our work is the evaluation of the effectiveness of preventive vertebroplasty of vertebra over the PSF in patients with osteoporosis.

Material and Methods:

The work consists of patients who were treated in our hospital over the vertebral osteoporotic fractures in the period 2012-2014. Osteoporosis was confirmed by performing CT densitometry. The study includes patients with a T-criterion from −2.5 to −4. PSF length was between 2 and 4 segments depending on the type of fracture. Between 4 and 8 screws were implanted to each patient. There were 51 people (34 women) aged 48-76 (mean 62 +/− 2) years. Screws with augmentation were implanted to all patients. Patients were divided into two groups: Group 1 - Control: 27 people - PSF with augmentation; Group 2 - Experienced: 24 people - PSF with augmentation plus prophylactic vertebroplasty of overlying vertebra. Preventive vertebroplasty was performed in the standard way. 7-9 ml of bone cement of high viscosity were introduced in the body of the vertebra by 2 Jamshidi needles. Surgical technique was comparable and performed by 3 surgeons of one department. All patients were discharged from clinic in satisfactory condition. There were no complications of surgical and infectious nature. Control examination was carried out after 3, 6, 12 and 24 months or in some problem cases.

Results:

Group 1 - control. Using the PSF with augmentation for the treatment of osteoporotic fracture ensured the stability of damaged segments soon after surgery. However, at different periods of time (3 to 9 months.) 7 (25.9%) cases of fractures of overlying vertebra were diagnosed and required surgery. Patients in this group had a normal life and were not exposed high-energy trauma. Group 2 - experienced. Using the PSF with augmentation combined with prophylactic vertebroplasty of overlying vertebra had provided the following results. Adequate stabilization of the affected segments was achieved. Overlying vertebra fracture was detected in 1 (4.1%) case. The patient suffering from epilepsy fell from the height of its own growth as a result of the attack, after a fracture of the vertebra was diagnosed and was located above the prophylactic vertebroplasty.

Conclusion:

Using vertebroplasty of overlying vertebra (in the volume of 7-9 ml.) is an effective way to prevent vertebral fractures over PSF. The method significantly reduces the number of revision surgeries.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577ec

A133: Comparison of Unipedicular versus Bipedicular balloon Kyphoplasty for Osteoporotic Vertebral Compression Fractures

Abstract

Introduction:

To evaluate the clinical results of a unipedicular balloon kyphoplasty for the treatment of osteoporotic vertebral compression fractures.

Material and Methods:

Between January 2011 and December 2014, 331 vertebrae of 297 patients, who underwent kyphoplasty for osteoporotic vertebral compression fractures, were analyzed. Group 1, with the bipedicular approach, consisted of 141 vertebrae of 143 patients with a mean age of 74.1 years. Group 2, with unipedicular approach, consisted of 190 vertebrae of 154 patients with mean age of 73.0 years. The plain radiographs, MRI and surgical records were reviewed.

Results:

In group 1, the mean VAS score changed from 7.29 to 2.73, the mean period of hospitalization was 3.10 days and the mean amount of cement infused was 7.32 cc. The degree of vertebral body collapse was 0.81, 0.73, 0.62 and 0.60 on follow-up, and 15 cases had fresh fracture. In group 2, the mean VAS score changed from 6.38 to 2.42, the mean period of hospitalization was 3.32 days and the mean amount of cement infused was 3.97 cc. The degree of collapse was 0.75, 0.67, 0.62 and 0.60 on follow up and 4 case had fresh fracture. The two groups showed no statistical significance for the change of the VAS score and the period of hospitalization, and the amount of cement was significantly less in group 2. The degree of collapse was not significantly different on the 4 times of follow-up. The frequency of fresh fracture was significantly less in group 2.

Conclusion:

There were no significant differences in clinical satisfaction and radiological results between the unipedicular and bipedicular kyphoplasty. The advantage of a unipedicular approach is the shorter procedure time than the bipedicular approach and less amount of cement. This is particularly useful in multi-level compression fractures.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577ed

A134: Percutaneous Vertebral Body Stenting and Bone Cement Augmentation Reduces Morbidity in Osteoporotic Spine Fractures

Abstract

Introduction:

The morbidity of osteoporotic vertebral fractures increases with the ageing of populations globally. Treatment options have ranged from simple immobilization to vertebroplasty with acrylate to formal open surgical stabilization with instrumentation. We studied the results of our treatment in which the affected vertebral body is stented from within before augmentation with acrylate.

Material and Methods:

Fifty patients with symptomatically painful osteoporotic fractures were treated throughout 2012 till 2014. They were followed up for 24 months. All were female, post-menopausal and had suffered osteoporotic fractures in the lower thoracic or lumbar spines or a combination of both. All had bone density deficits as documented by density scans, and suffered light to moderate degrees of Genant-type vertebral fractures. All were single-level injuries. Excluded were fractures due to secondary malignant spread, multiple-level fractures, injuries with neurological deficit, unstable fractures that required open surgical decompression and fractures that fragmented into the spinal canal. All patients were treated by the same surgeon. The procedure was an image-guided, percutaneous bilateral transpedicular insertion of a trocar that delivered a catheter-mounted, collapsed cobalt-chromium mesh (VBSTM, Synthes GmbH, Solothurn, Switzerland) into the corpus of the vertebra. The mesh is hydraulically expanded with an inner balloon to achieve vertebral height restoration before the balloon is deflated and withdrawn to accommodate polymethylmethacrylate injection. The patient is rested overnight and receives a chest radiograph in addition to a spine check radiograph before being discharged the next morning. We studied the efficacy of pain relief and the chronology of physical activity resumption in the short term and the incidence of adjacent fractures in the long term. The results were tabulated and statistical analysis applied to test for significance.

Results:

All patients experienced pain relief of varying degrees within 48 hours of the procedure. Forty six patients were able to resume physical activity and mobilise within 24 hours after the treatment while 4 required a longer time which did not exceed 72 hours after the procedure. Eight patients suffered cement leaks anteriorly or laterally into the peri-vertebral region, but which were of no clinical consequence. No pulmonary extravasation was encountered. At 24 months of follow-up, there was no worsening of the fracture profile and no adjacent vertebral fracture was encountered.

Conclusion:

We propose that vertebral body stenting has effectively relieved the symptoms of pain and radiographically restored vertebral body dimensions in our patients. It has been executed reliably without major complications, and has fared well in our patients even at a minimum of 24 months of follow-up. It has consistently prevented otherwise-deterioration of the fracture profile.

Disclosure

None of the authors received funds or benefits in any kind pertaining to this subject during the conduct of this study.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577ee

A135: Conservative Management of Osteoporotic Vertebral Fractures

Abstract

Introduction:

To present updated information on the conservative treatment of osteoporotic Vertebral Fractures.

Material and Methods:

Forty four consecutive patients, diagnosed with osteoporotic vertebral fracture, underwent the predetermined protocol of conservative treatment (bed rest, titrated analgesia, antiosteoporosis pharmacotherapy, bracing, and supervised physical therapy) after assessment of basic demographic data and clinical examination. They were evaluated every three months for nine months, using visual analog scale (VAS) for backpain, Oswestry Disability Index (ODI), and radiological parameters.

Results:

At nine months after treatment, there was a significant decrease in the VAS score (P < .0001) and the ODI score (P < .0001), with the final VAS score improving by 52.49% and the ODI score improving by 49.78% from the baseline. There was progressive increase in vertebral collapse (P = .032) with no change in kyphotic or scoliotic angles.

Conclusion:

Conservative treatment is effective in relieving pain and improving the spine function in such cases without obvious complications and can be therefore an alternative treatment to vertebroplasty or balloon kyphoplasty.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577ef

A136: Cement Leakage after Vertebroplasty: Correlation with Patterns of Compression Fractures and Bone Mineral Density

Abstract

Introduction:

To analyze the influence of fracture patterns and the result of bone mineral density on cement leakage after percutaneous vertebroplasty for osteoporotic vertebral compression fractures.

Material and Methods:

Between March 2014 and March 2015, 102 patients with single level osteoporotic compression fracture were treated by percutaneous vertebroplasty, and the clinical data were analyzed retrospectively. There were 15 males and 87 females, with a mean age of 79.1 years (range, 57-98 years). The patients were divided into cement leakage group and no cement leakage group by occurrence of cement leakage based on postoperative CT.

Results:

The incidence of leakage was 59.1%. Binary logistic analysis revealed that larger volume of bone cement (P < .001) and higher fracture severity grade (P < .001) were the strongest independent risk factors. Univariate analysis and multinomial logistic analysis showed that surgical approach (P < .001), gender (P =  .016), and operated level (P =  .032) were additional risk factors for leakage.

Conclusion:

High fracture severity grade and low viscosity of polymethylmethacrylate bone cement are general, strong, and independent risk factors for cement leakage. Using CT and MRI assessment, cortical disruption and the presence of an intravertrebral cleft were identified as additional strong risk factors regarding cortical (intradiscal) cement leakage, thereby potentiating anticipation.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577eg

Adolescent Scoliosis 2
A137: Direct Vertebral Rotation vs Single Concave Rod Rotation: Low-Dose Intraoperative Computed Tomography Evaluation of Spine Derotation in Adolescent Idiopathic Scoliosis Surgery

Abstract

Introduction:

It remains unclear whether SCRR manoeuvre alone causes Apical Vertebral Derotation (AVD) and rib hump correction. Although the influence of DVR on AVD and rib hump change has been described, it has been evaluated mainly with indirect methods. This is the first study to evaluate separately the derotational effectiveness of these two manoeuvres during the low-dose Intraoperative Computed Tomography (ICT). The aim was to compare the effectiveness of two main corrective manoeuvres: Single Concave Rod Rotation (SCRR) and Direct Vertebral Rotation (DVR) in regard to Apical Vertebral Rotation (AVR) and rib hump correction in Adolescent Idiopathic Scoliosis (AIS) surgery.

Material and Methods:

A study group consisted of 38 AIS patients treated by Posterior Scoliosis Surgery (PSS) with all pedicle screw constructs. The mean age when operated was 15.8 years (11.7 – 17.9 years). Written informed consent for the surgery and publication of this study and all images was obtained from each patient and the Medical University of Gdansk Ethics Committee approved the study. All examined patients had dow-dose ICT evaluation (before correction, after SCRR and after DVR) for the safe pedicle screws placement and for confirmation of screw position after corrective manoeuvres. During the first ICT, precorrectional AVR measure with Aaro&Dahlborn method was performed. AVD assessment was performed with our own method. In every case pre and post correctional rib hump angle was measured (Pleura –Pleura line and Spine – Sternum line ratio). All patients had pre and postcorrectional Cobb angle measurement on plain PA and lateral spinal radiographs. Lenke classification was used for the curve pattern evaluation. All patients had Intraoperative Spinal Neuromonitoring (ISN) performed. For statistical analysis SPSS 17v software (SPSS Inc.) was used. A paired Student T-test was used for the examination of statistical differences. R-Spearman test of correlation was used to evaluate the relationship between perioperative variables.

Results:

We found SCRR ineffective – mean postcorrectional AVR increased insignificantly 1.5° (16.1% worsening) P = .170. On the contrary, an average postcorrectional AVR after DVR decreased significantly mean 3.1° (33.3% improvement) P = .049. Precorrectional rib hump angle was 19.3°, after SCRR - 15° and after DVR - 12.3°. It was found that despite the lack of true derotation after SCRR there was a significant 22.3% decrease of the rib hump P = .043. Although the rib hump decreased significantly 36.3% after DVR as well P = .023. There was also significant difference between a rib hump angle after SCRR and DVR (P = .049).

Conclusion:

SCRR do not lead to AVD. The true spinal derotation is possible only when DVR systems are used. The decrease of rib hump is achieved both after SCRR and DVR, but the improvement is significantly better after DVR.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577eh

A138: Prognostic Factors of Uninstrumented Thoracic Curve Correction Above Selective Fusion for Lenke 5 Idiopathic Adolescent Scoliosis

Abstract

Introduction:

Spontaneous correction of uninstrumented overlying thoracic curves above selective fusion for Lenke 5 adolescent idiopathic scoliosis (AIS) is usually between 29% and 46%. It is known to be influenced by Thoracic Cobb Angle (TCA), TCA on bending, ratio thoracolumbar Cabb angle/TCA, thoracic kyphosis, growth stage and correction of main curve. To our knowledge, preoperative rib hump has never been expressly evaluated as a prognostic factor.

Aim:

To test rib hump and well-known parameters as prognostic factors of TCA at follow-up above selective fusion for Lenke 5 AIS.

Material and Methods:

Retrospective monocentric series of 48 Lenke 5 AIS, operated on by posterior selective construct with minimum 2 y follow-up. Demographic data, preoperative thoracic rib hump (measured in mm in trunk anteflexion as the distance between the horizontal tangent line to the apex of rib hump and the hollow of the contralateral ribs at the same distance from midline), frontal, sagittal and bending spinal parameters preoperatively and at last follow-up were recorded. Statistics were performed by STATA 9.2: T-Test to compare mean values, Pearson coefficient to assess correlations, Linear multiregression to assess predictability of final thoracic cobb angle.

Results:

Main thoracolumbar curve averaged preoperatively 47° (36° - 72°), at follow-up 12° (1° - 28°). Overlying TCA averaged preoperatively 26° (2° à 40°), at follow-up 16° (2° à 41°), that is correction = 37%. TCA difference between preoperative and follow-up was significant (P = .001). Final TCA was correlated to bending TCA (0,63), preoperative TCA(0,62) and rib hump (0,55). Multiregressions confirmed significance of bending TCA exceeding 20° (P = .001), preoperative TCA (P = .011) and rib hump (P = .012).

Conclusion:

Rim hump was proved to influence final TCA. In case of lenke 5 AIS and overlying curve with rib hump and /or TCA bending exceeding 20°, an extensive construct including both thoracolumbar/lumbar and thoracic curve should be discussed.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577ei

A139: Optimal Selection of the Lowest Instrumented Vertebra for Lenke Type 5 & 6 Thoracolumbar/Lumbar Major AIS Curves at Minimum 5 Year Followup

Abstract

Introduction:

Controversy still exists when selecting the lowest instrumented vertebra (LIV) in major TL/L AIS curves. The decision is typically to stop at L3 vs L4 but is more difficult when the preop L3-4 disc is parallel. We reviewed a large series of Lenke Type 5 & 6 TL/L curves assessing results of LIV selection relative to the lower end vertebra (LEV) and touched vertebra (TV) at 5 yr f/u. We hypothesized that fusing to the LEV in major Thoracolumbar/Lumbar Type 5 & 6 AIS curves will produce acceptable long term results except when the disc below the LEV is parallel (ie, L3/4). In those cases, fusing to the TV, (ie, L4) will lead to better balance & decreased disc angles postop.

Material and Methods:

106 Lenke Type 5 & 6 AIS curves were retrospectively reviewed from a large AIS database by 2 examiners who selected the TV from the center sacral vertical line (CSVL), and confirmed the LEV of the curve. The LIV distance from the CSVL (cm), LIV disc angle & overall balance at 5 yr f/u were evaluated. Patients were separated into 3 groups based on the L3-4 disc: open on the convex side of the TL/L curve (Open), closed on the convex side (Closed), or Parallel.

Results:

17/106 pts. were in the Open, 61 in the Closed & 28 in the Parallel group. There was a statistically inferior result of stopping at L3 vs L4 in the Open grp with increased LIV-CSVL distance (2 vs 0.7 cm, P = .005) & an increased postop Disc Angle (4 vs 0.2°, P = .003). The Parallel grp also had a statistically greater risk of increased LIV-CSVL translation for those fused to L3 vs L4 (P = .007, Figure 1). There was no difference in postop LIV distance or angle parameters for the Closed pts. with a L3 vs L4 LIV.

Conclusion:

For Type 5 and 6 TL/L AIS curves, one can reliably stop at L3 & expect a well-centered LIV with minimal disc angulation when the preop L3-4 disc is closed on the convexity of the TL/L curve, but should fuse to L4 when that disc is open on the convexity. When the L3-4 disc is parallel, patients with a L3 LIV will have a greater risk of increased LIV-CSVL translation vs a L4 LIV at minimum 5 yrs f/u.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577ej

A140: ISYQOL Discriminates Better than the SRS-22 Subgroups of Adolescents with Spinal Deformities

Abstract

Introduction:

Quality of life (QoL) is evaluated in spinal deformities by several questionnaires. Rasch analysis is a statistical methodology to develop good QoL questionnaires, and make them interval instead of ordinal measures. ISYQOL (Italian Spine Youth Quality of Life questionnaire) is the first questionnaire developed through Rasch analysis. The aim of the study was to compare the discriminative validity of ISYQOL versus the actual gold standard questionnaire (SRS-22).

Materials and Methods:

We performed a cross sectional study. We included in the study 1677 participants (1251 females), median age 14 years (1-3 quartile: 11-14) affected by scoliosis or hyperkyphosis. Consecutive patients of a tertiary outpatients clinic specialized in conservative treatment of spinal deformities completeted the SRS-22 (22 items, 5 categories per item) and ISYQOL (20 items, 3 categories per item) questionnaires before consultation. Multiple linear regressions were computed to predict ISYQOL measure or SRS-22 score (independent variables: age, gender, diagnosis, and bracing). A subgroup analysis was performed through linear regression modelling (variables: age, gender, Cobb degrees, brace dosage and type) to check if each questionnaire was able to discriminate QoL changes according to specific influencing factors.

Results:

SRS-22 and ISYQOL scores correlate (Spearman -0.68, R2 0.43, P < .001) but the best fit is a parabole (R2 0.51). With ISYQOL above 80% SRS-22 does not change (higher ceiling effect). SRS-22 and ISYQoL detect the effect of age, gender, diagnosis (scoliosis vs hyperkyphosis) and bracing (brace vs no brace) on QoL: F = 92.42 (P < .001) for ISYQOL and F = 85.59 (P < .001) for SRS-22. The variables explained 19% and 14% of the variability for ISYQOL and SRS-22 respectively. The QoL measured by ISYQOL is explained by: age (years), gender, Cobb degrees, brace hours per day and brace type (soft vs hard) (F = 10.69; P < .001; R2 = 0.11); SRS-22 by age and Cobb degrees only (F = 13.66; P < .001; R2 = 0.05).

Conclusions:

ISYQOL is correlated to SRS-22 but showed a reduced ceiling effect. Despite having considerably less items and categories, ISYQOL appears to be a better measure of QoL during growth in spine deformity individuals in a conservative setting.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577ek

A141: Use of Intraoperative Traction in Adolescent Idiopathic Scoliosis: Impact on Concave Apical Screws Density, Curve Correction and Functional Outcomes

Abstract

Introduction:

The use of intraoperative traction to facilitate pre-instrumentation curve correction and subsequent screw insertion is not widely practice. We analysed the impact of intraoperative traction as a strategy to optimize implant placement and improve the curve correction in adolescent idiopathic scoliosis.

Materials and Methods:

We reviewed retrospectively collected data of patients were consecutively operated at our centre by a single surgeon. Group A includes patients were operated during 2008-2011 without intraoperative traction and Group B between 2011-2013 with Skull tong and bilateral skin traction (Traction with 15% of body weight at skull tongs and 10-15% on each leg). Radiological parameters like apical rotation, concave apical screws density and correction of cobb angle and functional outcomes with SRS 22 questioners were measured.

Results:

Group A (no traction) had 72 patients (86% female) with a mean age of 15.5 years. Group B (traction) had 84 patients (88% female) with a mean age of 14.2 yrs. In group A pre-op mean major Cobb’s angle was 62.8 degree and final correction to 19.5 degree (71% correction). Group B - Pre-op mean major Cobb’s angle was 78.3 degree which reduced to 48.5 degree (40% correction) on traction film and final correction to 13.5 degree(83% correction, P < .001). Apical vertebral rotation changed from mean Nash-Moe grade of 2.6 to 2.2 with traction (P = .011). Concave apical implant density (CAID) was calculated by apical concave sided implant ratio in apical and adjacent vertebra, measured as 87% under traction compared to 26% without (P < .0001). SRS-22 postoperative outcomes showed mean final score of 4.3 in group A and 4.38 in group B with no statistical difference between the groups (P = .66). No complication in relation to traction was observed in group B.

Conclusions:

Intraoperative traction decreased apical vertebral rotation, allowed for easier placement of apical screws improving the implant density and final curve correction. This technique obviates the need for complex osteotomy techniques and excessive correction manoeuvres to correct larger curves.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577el

A142: The Development of an Adolescent Spine Deformity Surgery Core Outcome Set for the Nordic Spine Registries: A Project Supported by the AOSpine Knowledge Forum Deformity

Abstract

Introduction:

Routine patient-related outcome monitoring is gaining importance in medical care. Healthcare providers are putting more emphasis into assessing the value (health gain per unit cost) of treatment provided.1 However, outcome registries are most valuable if they are comparable between countries and include outcomes that are relevant to the patient population of interest.2,3 The COSSCO (Core Outcome Set for SCOliosis) project aims to reach consensus, across the Nordic Spinal Deformities Societies (Sweden, Denmark, Finland, Norway, The Netherlands), about which patient-relevant outcome domains (e.g. appearance) and subsequent measurement instruments (e.g. SRS-22) are to be included in the 5 national spine outcome registries for adolescents and young adults (10-25years) with a spinal deformity undergoing surgery.

Material and Methods:

A systematic literature review and quality assesment of existing patient-reported outcomes (PROs) used in adolescent spine deformity studies were conducted. To identify reported outcome domains, PROs were linked to the WHO’s International Classification of Functioning, Disability and Health (ICF) framework. Spinal deformity surgeon representatives from each of the NSDS countries were invited to participate in a modified Delphi study. They were asked to vote which of these outcome domains were considered essential to measure in every patient. The first consensus round was held face-to-face. The second and third round consisted of web-based surveys.

Results:

A total of 26 PROs were identified in 191 papers that met the inclusion criteria. This provided a list of 39 potential core domains. Through three Delphi rounds, consensus was reached on 14 “core outcome domains”. Existing PROs were studied to identify which core outcome domains they measure, how much time is required to complete them, the availability of validated translations in the Nordic languages and quality metrics.

Conclusions:

Based on this analysis, the study group advises the implementation of a combination of SRS-22, EQ-5D and a yet to be defined respiratory questionnaire in the Nordic registries as the appriopriate instruments to cover all core outcome domains. A further consensus round will be held on the proposed combination of instruments. The results will be validated among patients (and their parents) and translated into an outcome standard that can be implemented in the Nordic spine registries. The development of this core outcome set will facilitate comparison across registries and will ultimately improve the quality of daily clinical practice by routinely measuring outcomes of care, enabling continuous evaluation and improvement.

References

1. Porter, M. E. A Strategy for Health Care Reform — Toward a Value-Based System. N. Engl. J. Med. 361, 109–112 (2009).

2. Porter, M. E., Larsson, S. & Lee, T. H. Standardizing Patient Outcomes Measurement. N. Engl. J. Med. 374, 504–506 (2016).

3. Selby, J. V., Beal, A. C. & Frank, L. The Patient-Centered Outcomes Research Institute (PCORI) National Priorities for Research and Initial Research Agenda. JAMA 307, 1583 (2012).

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577em

A143: Is There Still a Place for Convex Hemiepiphysiodesis in Congenital Scoliosis in Young Children? A Long Term Follow-up

Abstract

Introduction:

Nowadays, hemivertebra(HV) resection followed by limited fusion and instrumentation is the most used procedure in the treatment of congenital scoliosis in children with HV. This procedure has its well-known risks (particularly neurologic). The purpose of this study is to evaluate the long term results of anterior and posterior convex hemiepiphysiodesis used to treat congenital scoliosis with HV and to evaluate its effect on coronal deformity correction.

Material and Methods:

This is a retrospective descriptive study performed on 30 children with 33 congenital scoliotic curves operated on using a one staged double approach (anterior+posterior) hemiephysiodesis by bone grafting of the convex side of the curve without instrumentation. A post-operative cast is worn for 3 months. We defined a “Limited Fusion” as the one centered on the HV and including the 2 adjacent levels. An “Extensive Fusion” is the one that is carried on more than one adjacent vertebra to the HV, proximally or/and distally. Patient’s mean age at surgery was 3 years (6 months to 12 years), with an equal distribution of genders and a mean frontal Cobb angle of 42.5°. The mean follow up is 15 years (8 to 25 years). There were 23 isolated HV and 10 HV associated to a congenital bar(CB). Limited Fusion was performed on 21 curves with a mean angle of 37° while Extensive Fusion was performed on 12 curves with a mean angle of 50°.

Results:

Overall results showed a frontal Cobb angle reduction from 42.5° (18° - 80°) to 29.5° (2° - 77°). Detailed analysis showed that 22 curves had a mean correction of 47% (41° to 21.6°), 8 curves were stabilized (mean Cobb = 38°) and 3 curves had a mean aggravation of 16% (53.7°→64.3°). Subgroup analysis took into account age at surgery, type of the malformation, and Cobb angle. It showed: 57% correction in patients aged <3 years and 32% in patients aged >3 years; 55% correction in curves with isolated HV compared to 26% correction in curves with HV and CB; 65% correction in curves <35° compared to a 40% correction in curves >35°. The best correction with Limited Fusion (71%) occurred in case of an isolated HV, with a curve less than 35° and a surgery performed before age of 3. Limited Fusion in patients aged >3 years, with a HV associated to a CB, and a Cobb angle >35° showed a deterioration in 50% of cases, while Extensive Fusion showed a stabilization in 50% and even a mild amelioration in 50% of these patients.

Conclusion:

A limited convex hemiepiphysiodesis still have a place in congenital scoliosis care, sparing the patient the risks of vertebral resection and instrumentation, fusing the same number of levels, when it is performed in case of isolated HV, in curves less than 35° and in children younger than 3 years old.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577en

A144: ISYQOL: New Quality of Life Questionnaire for Adolescents with Spinal Deformities Developed through Rasch Analysis

Abstract

Introduction:

Spinal deformities are usually associated with poor quality of life (HRQoL). Several questionnaires have been developed to evaluate HRQoL in idiopathic scoliosis (the SRS-24, SRS-22, the SQLI and the EOSQ for early onset scoliosis). Rasch analysis is able to turn ordinal scale measures into interval, with obvious clinical and research advantages. Only the SRS-22, the most widely used questionnaire, has been evaluated with Rasch analysis, but showed poor clinimetric properties after Rasch analysis application. The aim of this study was to develop a new questionnaire (ISYQOL: Italian Spine Youth Quality of Life questionnaire) able to satisfy the fundamental requirement for Rasch analysis, for HRQoL evaluation in adolescents with spinal deformities.

Materials and Methods:

A multistage classical methodology has been used: content analysis of the posted messages by adolescents with spinal deformities in an internet forum (developed in 2006, including 5758 posts and 1156 answers from expert clinicians), to guide the items selection; an opinion poll among 23 experts provided a first version of the questionnaire, with 50 possible items; test of the first draft of the questionnaire (50 questions) in 94 patients; Rasch analysis to generate the second version of the questionnaire (23 questions) that was tested again in 39 patients; finally, 402 participants filled out the last version of the ISYQOL in the waiting room, immediately before medical evaluation. To analyze the data Rasch analysis was performed by using Winsteps Rasch Measurement software (2009, version 3.69.1; partial credit model).

Results:

We found that 20 items fitted the model and constituted the final version of the ISYQOL questionnaire. Differential Item functioning was significant for brace (−0.87 vs −1.62 logit, respectively; P = .0015), thus allowing comparison among patients with and without brace. The principal component analysis on Rasch residual confirmed the unidimensionality of the ISYQOL. The finding of an addition variable hidden in the ISYQOL Rasch residuals (1st factor Eigenvalue = 2.2) explains 5.2% of the total data variance. Participant reliability of ISYQOL is 0.83 and thus ~3 significantly different strata can be discerned in the sample.

Conclusion:

The present work presents the ISYQOL, the first questionnaire developed in the Rasch setting which measure HRQOL in adolescents with spinal deformity. Being Rasch consistent, ISYQOL offers an HRQOL measure which is additive, generalizable and unidimensional thus complying with requirement of a genuine continuous measure. ISYQOL can offer an insight on the impact of the brace prescription.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577eo

A145: Magnetically Controlled Growing Rods with Maximal Distraction: A New Mode of Failure

Abstract

Introduction:

Early reports of magnetically controlled growing rods (MCGRs) have demonstrated promising results in the management of early onset scoliosis (EOS). However incidence of device failure has been reported in 0-50% of cases. The reasons for this variation, and the risk factors for device failure, are poorly understood. Similarly, consensus regarding optimum distraction technique, frequency and amount is lacking.

Materials and Methods:

A retrospective case series of all patients treated with MAGEC (MAGnetic Expansion Control, Ellipse Technologies Inc, Aliso Viejo, CA, USA) rods at a tertiary referral centre was performed. Patient notes and radiographic images were reviewed. Coronal Cobb angles, thoracic height (T1-T12), spinal height (T1-S1) and total rod distraction were measured independently by two authors. Rods were implanted as described by Cheung et al. Subsequent distraction took place at 3 monthly intervals. Each occasion the rods were distracted maximally until clunking was heard. Failed rods were explanted and analysed by an independent team of specialists. Rods were disassembled and the actuator casing was cut open to allow examination of the inner components.

Results:

11 patients at our institute had MAGEC rods implanted with 8 meeting the minimum follow up (3 male, 5 female). Average age was 10.1 years. Two had syndromic EOS curves, six were idiopathic curves. Dual rod constructs were used in all cases. Patients underwent an average of 9.5 distractions over a period of 33.3 months. Mean pre-operative Cobb angle was 63.0° and improved to 41.4° following surgery (P = .02). This was maintained at 37.7° (P = .56) at most recent follow up. Thoracic T1-T12 and T1-S1 spinal heights were also significantly improved following surgery (P = .003 and 0.001) and subsequent distraction. 5 patients encountered complications: pain during distraction (n = 1), failure to distract on at least one occasion (n = 4), proximal screw pullout (n = 1) and device failure requiring explantation (n = 3). In two cases, separation of the lead screw from the radial bearing, as a result of drive pin fracture within the actuator portion of the device, was seen radiographically. A third patient’s rods were explanted due to curve progression despite normal radiological images. In this case, pistoning of the rods was seen at the time of surgery. All explanted devices displayed evidence of impingement between the lengthening rod and internal actuator casing. Titanium oxide debris was seen between the magnet and the internal aspect of the outer casing. This debris is thought to bring about device failure by preventing the actuator magnet rotating. Fractured drive pins were found in five of six explanted MCGRs.

Conclusion:

Our results support the notion that MCGRs are an effective method of spinal growth guidance in patients with EOS. We report higher rates of implant failure than other series using dual rod constructs. We postulate that our higher incidence of mechanical failure is due to over stressing the rods during maximal distraction to the point of clunking.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577ep

Cervical Myelopathy
A146: Combinatorial Surgical and Neuroprotective Therapy for Cervical Spondylotic Myelopathy Results in Improved Neurological Function: From Preclinical Proof of Concept to a Phase III Randomized Controlled Trial

Abstract

Introduction:

Surgical decompression is an effective treatment for cervical spondylotic myelopathy (CSM). However, a number of patients continue to experience substantial neurological impairment post surgery. Riluzole has neuroprotective effects in injuries of the central nervous system. To determine the efficacy of riluzole for promoting neurological improvement in CSM following decompression, we performed a pre-clinical proof of concept experiment and then we translated our work and established a Phase III multi-center randomized controlled clinical trial (CSM-Protect).

Material and Methods:

Surgical decompression was performed in a rat CSM model and riluzole, or control, was administered. Spinal cord blood flow (SCBF) was evaluated in all CSM rats, in vivo, before and after decompression using FAIR MRI. The long-term outcomes of decompression with or without riluzole treatment determined using neurobehavioural and neuroanatomical assessments. Our multi-center double-blind randomized CSM-Protect trial includes a total of 300 CSM patients undergoing decompression surgery and randomized 1:1 to receive riluzole (2x50 mg daily for 14 days before and 28 days post surgery) or placebo treatment. MJOA score will determine the effectiveness of the combinatorial treatment at 6 months following surgery. Statistical analysis will be performed as a sequential adaptive trial with interim analysis.

Results:

Rats receiving combinatorial treatment displayed long-term significant neurological improvements associated with preservation of motor neurons and corticospinal tracts compared to rats treated with decompression alone. Riluzole also dramatically reduced the extent of ischemia-reperfusion injury post surgical decompression in our animal model. At present, 274 subjects have been enrolled into the CSM-Protect trial. A planned interim analysis using this sample has commenced.

Conclusion:

The proposed combinatorial therapy promotes neurological recovery in CSM rats. Confirmation of this proof of concept has been translated from bench to the bedside and we are currently running the CSM-Protect trial to determine the efficacy of this combinatorial treatment option for use in CSM patients.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577eq

A147: Congenital Cervical Spine Stenosis in a Global Cohort of Patients with Degenerative Cervical Myelopathy: A Report Based on a MRI Diagnostic Criterion

Abstract

Introduction:

Congenital Spinal Stenosis (CSS) is a known predisposing factor for Degenerative Cervical Myelopathy (DCM). Previous studies have suggested that an AP canal diameter less than 12-13 mm or a Torg-Pavlov ratio (TPR) of <0.82 are indicative of CSS. However, these studies are based on radiographs and cadaver studies, and do not take into account the variability in the spinal cord size between individuals. In a global cohort of patients with DCM, MRI-based criteria were developed to diagnose patients with pre-existing CSS. Furthermore, patient characteristics and surgical outcomes were compared between patients with and without CSS.

Material and Methods:

Patient and MRI data were derived from two international prospective and multicenter studies. A total of 349 MRIs were available for quantitative analysis. Spinal canal and spinal cord anteroposterior diameters were measured above and below the region of interest at non-compressed sites, and an average spinal cord occupation ratio (SCOR) was calculated. A SCOR of ≥70% was used to diagnose patients with CSS. Additionally, a TPR and spinal canal diameter at C3 and C5 were measured on lateral radiographs. Clinical and MRI factors were compared between patients with and those without CSS using t-tests. Multiple linear regression was used to assess the impact of CSS on surgical outcome. Sensitivity analysis was conducted to assess CSS at a lower SCOR threshold (≥65%).

Results:

Calculation of SCOR was feasible in 311/349 patients (89%), as reference levels free of pathology were not present in the remainder of patients. Twenty-six patients with CSS were identified (8.4%). Patients with CSS were younger than patients without CSS (50.8 vs. 56.3, P = .03) and had worse baseline severity as measured by the mJOA (P = .04), Nurick (P = .05) and NDI (P < .01). CSS patients also presented more commonly with T2 cord hyperintensity changes (P = .09), and worse SF-36 Physical Component scores (P = .06), though these factors did not reach statistical significance. After adjusting for age and baseline severity, there were no statistically significant differences in surgical outcomes in patients with or without CSS. SCOR was correlated with TPR and spinal canal diameter at C3 but not C5. A SCOR ≥65% identified patients with a younger age and a lower TPR and canal diameter at C3, but showed no differences in baseline neurological impairment when compared to patients with a SCOR <65%.

Conclusion:

SCOR’s conceptual validity derives from its inclusion of both the size of the spinal canal and cord. A SCOR cut-off of ≥70% has shown to objectively identify CSS in patients with DCM. This is supported by the finding that DCM patients with CSS are more likely to be younger and present with worse neurological impairment and function. However, despite greater functional impairment preoperatively, CSS patients have comparable duration of symptoms, MRI presentations, and surgical outcomes as DCM patients without CSS. On the basis of these findings, SCOR appears to be an effective alternative to TPR or spinal canal diameter as a diagnostic criterion for CSS.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577er

A148: Multilevel Cervical Spondylo-arthopaty with or without Myelopathy: Evaluation of Long Term Follow-up between Anterior and Posterior Approach

Abstract

Introduction:

Multilevel cervical disc disease is a common degenerative disease that is characterized by compressions in the cervical region of the spine; firstly, the interbody disk degeneration and secondly, the sub-sequent deterioration of the facet joints, the thickening of the posterior longitudinal ligament and of the legamentum flavum, lead to progressive compression of the nervous system and, thus, produce myelopathy. As we well know, the treatment is surgical but the gold standard of the technique, especially of the approach, remains controversial and is based on the surgeon experience.

Materials and Methods:

From 2008 to 2015 we have collected data from archive and we performed this retrospective study which included 304 consecutive patients (187 males and 117 females) that undergoing surgery for multilevel spondylotic disease. Then the patients have been divided into two groups according to surgical approach: anterior (n = 284) and posterior (n = 28). Among them, we selected only the patients of whom surgery has been involved ≥3 intervertebral segments. According to these strict criteria we enrolled 20 patients underwent posterior approach and 12 by the anterior one. The average follow-up was 4 year and 6 months long. We evaluated either clinical parameters and radiological issues before and after surgery.

Results:

Among the anterior group the patients selected, even with signs of myelopathy, had a better pre-op clinical status either under neurological and general point-of view. Apart that, the selection of the approach has been made on the surgeon preference and thus there’s a slight predilection for the posterior one. The rate of clinical complications, such as temporary dysphagia and or dysphonia was obviously much higher on the anterior group than the posterior. On the posterior group, we had two cases of reoperation due to a screws pull-out, both of them over 1-year of follow-up. The neural recovery rate appeared to be the same between the two groups.

Conclusion:

Our study clearly shows that there are not significant differences, in terms of clinical and radiological outcome, on the follow-up, even on a long-term one between anterior and posterior approach for multiple level spondylotic cervical disease. We noticed that patients underwent anterior approach tend to have a better post-operative neural function than posterior ones; in the meantime, there is no substantial difference in the clinical recovery rate. This apparently paradoxical result could be explained by better neurological pre-op status of the anterior approach group. We might assume that, when the surgeon is sufficiently skilled on the posterior approach, the choice of the approach should be tailored made, case by case.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577es

A149: Prediction of Outcome following Surgical Treatment of Cervical Myelopathy Based on Features of Ossification of the Posterior Longitudinal Ligament: A Systematic Review

Abstract

Introduction:

Ossification of the posterior longitudinal ligament (OPLL) is defined as ectopic bone formation within the posterior longitudinal ligament. Although various OPLL features (the extent, shape, and thickness of OPLL as well as the presence of dural ossification) have been defined in the literature, there are no systematic reviews that summarize the associations between these features and clinical outcomes following surgery. The objective of this study was to conduct a systematic review of the literature to determine whether OPLL characteristics are predictive of outcome in patients undergoing surgery for cervical myelopathy.

Material and Methods:

An extensive search was performed using four electronic databases: MEDLINE, MEDLINE in Process, EMBASE and Cochrane Central of Controlled Trials. Our search terms were OPLL and Cervical. We identified studies in English or Japanese that evaluated the association between cervical OPLL features and surgical outcome. The overall body of evidence was assessed using a scoring system developed by the Grading of Recommendation Assessment, Development and Evaluation (GRADE) Working Group with recommendations from the Agency for Healthcare Research and Quality (AHQR). This systematic literature review is formatted based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement.

Results:

The search yielded a total of 2318 citations. A total of 28 prognostic cohort studies were deemed relevant following a rigorous review process. Among them, only seven retrospective studies conducted a multivariate analysis that controlled for potential confounding variables. Sample sizes ranged from 47 to 133 surgical patients. The main outcome was postoperative Japanese Orthopedic Association (JOA) score and/or recovery rate in six studies and Nurick grade in one. Of these, two were rated as Level II and five as level III evidence. Based on our results, low evidence suggested that patients with a hill-shaped ossification have a worse postoperative JOA score following laminoplasty than those with a plateau-shaped lesion. Based on low evidence, the space available for the spinal cord cannot predict postoperative JOA scores. Furthermore, there is no association between occupying ratio and improvement on the Nurick scale (moderate evidence). There is insufficient evidence to determine the association between JOA outcomes and type of OPLL, presence of dural ossification and occupying ratio.

Conclusion:

Patients with hill-shaped OPLL have a worse postoperative JOA score than those with plateau-shaped ossification after laminoplasty. Occupying ratio, type of OPLL and the presence of dural ossification are not predictive of surgical outcomes following either anterior or posterior decompression. There are limited articles that used a multivariate analysis to evaluate the association between clinical outcomes and OPLL features. Further high quality studies are needed.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577et

A150: Correlation and Profile of Quality of Life and Functional Outcome Measures for Cervical Spondylotic Myelopathy after Surgery

Abstract

Introduction:

In the present study we sought to 1) investigate the profile of functional outcome assessment by evaluating the modified modified Japanese Orthopaedic Association (mJOA) and quality of life by SF-36, 2) investigate the correlation between quality of life and functional outcome measures at different follow-up time, and then 3) further understand the ability of the various measures to predict favorable quality of life (health transition item) at different follow-up time for patients undergoing operation for CSM.

Material and Methods:

We used mJOA assessment and the SF-36 to preoperatively evaluate the patients and again in continuous follow-ups conducted at three months, one year and more than two years after surgery. For evaluating the profile of health status measures (HSMs), changes in clinical effects in each group after surgeries were analyzed by the Wilcoxon rank-sum test. For investigating the correlation between the two HSMs, we computed the Spearman rank correlation analysis. To assess each HSMs’ ability to discriminate HTI, we performed receiver operating characteristic (ROC) curve, area under the curve (AUC) and Spearman rank correlation analysis.

Results:

280 CSM patients were enrolled and the mean time of last follow-up was 50.5 months. 1. The mJOA score was improved significantly at any follow-up time. At three months after surgery, the recovery of sensory function was better than motor function, while at one year after surgery and at the final follow-up time, the recovery of sensory and motor function had no significant difference. The mJOA score peaked 16.4 months after the surgery. Before surgery, all patients’ QoL showed varying degrees of decreases in all sections compared to normal population. Two sections—role-physical, and role-emotional—showed the most significant declines. After surgery, with the exception of general-health and social-function at three months after surgery, all the other items at every follow-up time all showed significant improvement. The maximum recovery time point of the physical component score (PCS) was 20.1 months and mental component score (MCS) was 24.1 months after surgery. 2. We found a correlation between improvement in the mJOA score and PCS at 3 months after surgery, but not in MCS. While at 1 year after surgery and the final follow-up, the improvement of mJOA was associated with both PCS and MCS. 3. The AUC and correlation coefficient of PCS showed the highest of the four measures. The recovery rate of mJOA appeared to be the most accurate discriminator at one year after surgery. As for the final follow-up, the results were not consistent as the recovery rate of mJOA showed the highest AUC and the highest correlation coefficient was for MCS.

Conclusion:

CSM patients can benefit from surgical treatment by significant improvement of neurological function and quality of life, with sensory function and PCS recovering more quickly than motor function and MCS. mJOA (16.2 months), PCS (20.1months) and MCS (24.1 months) reached their maximum recovery points in order. The most responsive indicator varies depending on the follow-up time.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577eu

A151: Functional and Clinical Outcome after Circunferential Decompression (360 Degrees) Surgical Treatment of Severe Degenerative Cervical Spondylotic Myelopathy in the Elderly Patients

Abstract

Introduction:

Cervical spondylotic myelopathy (CSM) is a chronic-degenerative disease and one of the most common causes of spinal dysfunction associated with high morbidity in elderly patients as a result of the diagnosis is made at a very advanced stage of the disease and the only surgical treatment option to benefit this age group with moderate or severe myelopathy. The objective of this paper is to present our results of decompressive spinal surgery for anterior and posterior (surgery 360) via a surgical time, in patients with CSM with severe stenosis of the cervical canal, evaluating functional benefit vs risk, retrospective, linear analysis.

Material and Methods:

Registration of elderly patients aged 65old was obtained, with diagnosis CSM severe by scale clinical evaluation with Nurick, and m JAO <12, correlated by severe compression by imaging studies (x-ray, MRI) all received strong pulmonary physiotherapy preoperatively and those surgery 360 was performed with anterior corpectomy and Laminectomy Posterior instrumentation for fusion and fixation with neurophysiological monitoring intraoperative, analyze surgical results (operative time, blood loss) and complications 12 months of treatment.

Results:

We collected 37 patients with severe cervical myelopathy, Nurick V; 86.4% mJAO > 95%, 22 men, 15 women, mean age of 75 years (range 65-81 years) to 12 months was obtained acceptable clinical changes, Nurick 1; 10%, 2; 54%, 3; 29%, 4; 8%. By analysis of mJAO 78% change to moderate myelopathy, our morbidity prevalence was 16% in the first three months of preoperative disability related to increased monitoring.

Conclusion:

These results show that surgery 360 decompressive in a single surgical time, is an effective procedure that improves functional neurological outcome and quality of life in patients with CSM severe than one year, which detect which is mainly influenced by the preoperative duration of symptoms, with minimal morbidity and acceptable fusion, maintains cervical lordosis as demonstrated in other reports in the literature.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577ev

A152: Increased Segmental Range of Motion is Correlated with Spondylolisthesis in the Cervical Spine after Laminoplasty

Abstract

Introduction:

Cervical laminoplasty for cervical spondylotic myelopathy causes reduced range of motion (ROM), possibly due to the unintended contracture of the facet joint or a bony union. Though it is rarely studied, ROM may also increase following laminoplasty. Thus far, there are no reports describing the correlation between increased segmental ROM and segmental spondylolisthesis after laminoplasty. The aim of this study was to determine the incidence of increased segmental ROM after laminoplasty and to clarify whether increased ROM is associated with spondylolisthesis. Finally, we explored the effect of increased segmental ROM on clinical results.

Material and Methods:

We evaluated 187 segments from 39 cervical spondylotic myelopathy patients who underwent bilateral open door laminoplasty from C2 to C7. The segmental ROM and spondylolisthesis were measured using dynamic radiographs that were obtained preoperatively and 2 years postoperatively. The Japanese Orthopaedic Association (JOA) score was used for clinical evaluation. To compare the clinical results, we compared the cases with increased ROM in at least one segment to the remaining cases.

Results:

Increased segmental ROM (ie, ≥5° increase) was observed in 25/187 segments (13.4%) from 14 cases. There was a strong correlation between increased ROM and spondylolisthesis. A high preoperative disc height was associated with increased segmental ROM 2 years post-operation. Regardless of the correlation with spondylolisthesis, there was no statistically significant correlation between increased segmental ROM and JOA score.

Conclusion:

The decrease in segmental ROM after laminoplasty was not uniform. Approximately 13.4% of all segments showed increased ROM. The preoperative disc height might influence the risk for increased segmental ROM. Furthermore, increased ROM was correlated with spondylolisthesis in the segment, though it was not correlated with clinical results.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577ew

A153: Cervical Fusion with Expandable Corpectomy Device

Abstract

Introduction:

Cervical spondylotic myelopathy represents the most common indication for surgical treatment in cervical spine, with multiple therapeutic options and implants for treatment. Objective: To evaluate the clinical and radiological results when using an expandable vertebral body prosthesis PEEK plate based along a dynamic anterior plate for the ventral reconstruction of the cervical spine after several levels corpectomy.

Materials and Methods:

From April 2008 to April 2015, 39 adult patients with the diagnosis of cervical spondylotic myelopathy, underwent corpectomy by anterior approach and application ECD implant (expandable cervical device) and osteosynthesis with dynamic anterior plate. Their clinical course was evaluated by the modified scale of Japanese Orthopaedic Association (M-JOA) and Nurick grading system. The fusion and keeping the correct cervical lordosis was measured with cervical spine radiographs obtained pre-operative, immediate post-operative and 12 months after surgical intervention.

Results:

97.4% of patients achieved segment fusion at 12 months, the average correction of lordosis was 13.43 ± 0.76 degrees [var pi], the interbody height at 12 months posterior to surgery decreased on average 0.82 ± 0.37 mm [var pi], clinical evaluation presented significant improvement in both used scales. By comparing the number of segments and specific approached segments, we found that the group with better improvement in Nurick and M-JOA scales is that of two-segment corpectomy in the C3 and C4 levels, followed by the one-level corpectomy at C4 group. The one with less segment height loss at 12 month follow-up was the two-level group at C5 and C6.

Conclusion:

Utilizing ECD after a cervical corpectomy is an effective and valuable technique as an alternative in the treatment of spondylotic myelopathy cervical and other conditions that may require it, concentrating its benefit in correcting lordosis at a long term compared to other techniques and implants available nowadays.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577ex

A154: To Evaluate the Results of a Single Staged Simultaneous Decompression Surgery for Tandem Spinal Stenosis: A Review of 149 Patients

Abstract

Introduction:

Tandem spinal stenosis (TSS) is defined as spinal stenosis that combines cervical and lumbar spinal stenosis. The primary manifestations include intermittent neurological claudication, progressive gait disturbance, and mixed symptoms and signs of the upper and lower extremities. The incidence of tandem spinal stenosis among patients requiring surgery for spinal stenosis is low, and there is limited existing literature on this topic. There is a controversy in the management of these patients.

Aim:

The Aim of our study is to evaluate the results of a single stage simultaneous decompression surgery for patients with TSS.

Methods:

Between 1994 and 2014, 149 patients were diagnosed with TSS in a series of 3196 patients who underwent surgery for spinal stenosis (4.6%). Medical records of these 149 patients were studied. Results were evaluated using Nurick’s grade, modified Oswestry disability index (ODI), blood loss, operative time and complications.

Results:

The ODI score improved from a mean of 69.14 preoperatively to 31.12 at 12 months and 22.04 at final follow-up. The average Nurick’s grade improved from 3.7 preoperatively to 1.82 at 12 months and 1.21 at last follow-up. The average blood loss was 750 ml and average operating room time was 170 min. We had one patient with post op paraplegia who did not recover and 2 patients with Upper limb weakness, which completely recovered at subsequent follow-up.

Conclusions:

TSS is a rare condition that requires surgical treatment. A single stage simultaneous decompression surgery is an effective approach with excellent outcomes.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577ey

Lumbar Surgery 1
A155: Reposition of Vertebra in Low-Grade Lumbar Spondylolisthesis: Influence on the Clinical Outcome and Shape of Lumbar Lordosis

Abstract

Introduction:

Many studies on sagittal balance in spondylolisthesis have been published; most of them investigate isthmic spondylolisthesis, yet only a few address degenerative spondylolisthesis. North American Spine Society (NASS) clinical guidelines in diagnosis and treatment of degenerative lumbar spondylolisthesis advocate that there is insufficient evidence for or against the use of reduction with fusion. The purpose of current study was to find out whether reduction of the slipped vertebra influences postoperative sagittal spino-pelvic parameters and clinical outcome following posterior fusion in patients with low-grade degenerative spondylolisthesis of a single L3/L4 or L4/L5 lumbar segment.

Materials and Methods:

Seventy-six patients were included in the prospective study. Full-spine lateral radiographic scans in standing position were taken before and after the procedure, where parameters of sagittal balance, reduction of slipped vertebra and the shape of the lordosis were measured. Clinical improvement was monitored by Oswestry disability index (ODI) questionnaire and Visual Analogue Score (VAS) before surgery and one year after surgery.

Results:

No direct relation between reduction and clinical outcome could be demonstrated. There was a significant positive correlation between reposition and lumbar lordosis (r = +0.29, P = .005) and lordosis of the segments above the slipped vertebra (r = +0.191, P = .049). There was a weak negative correlation between reduction and lordosis of segments below the affected level (r = −0.138, P = .117) and lordosis of the disc L5/S1 (r = −0.149, P = .098). Insignificant negative correlation existed between reposition and sagittal vertical axis (r = −0.116, P = .158); when patients were divided in groups according to progression or reduction of the slip again no statistical significance was found (+21.6±28.9 mm vs. +16.7±38.5 mm, P = .59).

Conclusion:

Results of the current study imply that although reduction of slippage cannot significantly enhance the clinical improvement, it does have effect on sagittal re-balancing of the spine.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577ez

A156: Can Liposomal Bupivacaine Be Safely Utilized in Patients Undergoing Spine Surgery?

Abstract

Introduction:

Post-operative pain management in surgical patients is strongly correlated with patient satisfaction. There are many strategies utilized, however, most of these strategies are based on narcotics. Given the multiple adverse effects related to narcotics, other strategies have been used. Among these different strategies, the use of liposomal bupivacaine (LB) has provided successful pain relief but the safety has never been evaluated in patients undergoing spine surgery. We attempted to report preliminary results on the side effect profile of LB in patients undergoing posterior laminectomy and instrumented spinal fusion procedures. Our secondary outcomes were readmission rates and length of stay (LOS).

Material and Methods:

Under Institutional Review Board (IRB) approval, a retrospective review of patients from August 2015 to July 2016 who underwent posterior decompression and instrumented spinal fusion procedures in which LB was used for pain management was performed (N = 33) and compared to a placebo cohort of patients who received sterile saline in similar procedures (N = 21) from an ongoing prospective trial. An alpha error of less than 5% was used to set the threshold for significance for statistical analysis. The study cohort had a mean age of 60.8 years, which was equivalent to the mean age of 61.5 years in the control group (P = .825) and the BMI was also equivalent (29.7kg/m2 versus 31.1kg/m2, P = .402). Both cohorts were similar with the number of decompressed (3.30 versus 3.71; P = .151), and number fused vertebrae (2.91 versus 2.38; P = .053).

Results:

No significant difference in rates of most common complications between study and control groups including surgical site infections requiring antibiotics 6.1% versus 0%(OR = 3.4, 95% CI of 0.2 to 74; P = .4355), hypotension of less than 90 mmHg systolic 21.2% versus 14.3%(OR = 1.6, 95% CI of 0.37 to 7.1; P = .53), or urinary retention requiring a straight catheter or replacement of Foley catheter 12.1% versus 14.3%(OR = 1.3, 95% CI of 0.30 to 6.0; P = .71), respectively. Interestingly, there was a significant difference between the study and control groups in regards to nausea and/or emesis: 36.4% vs 9.52%(OR = 5.4, 95% CI of 1.1 to 27; p = 0.041). Readmission rates were 0 out of 33 for our study group and 1 out of 21 for our control group (OR 4.9, 95% CI of 0.2 to 126; p = 0.3). One patient from the study group expired secondary to causes unrelated to surgery after being discharged from the hospital. LOS between study and control groups were, 89.0 vs 92.2 hours(p = 0.760), respectively.

Conclusion:

LB did not lead to increased rates of complication, with the exception of nausea and/or emesis. While the increased rate of nausea and/or emesis was significant, further higher powered studies are necessary to make definitive conclusions on this significance given large uncertainty seen in the wide confidence interval. We also aimed this review at determining if a rebound pain phenomenon leads to readmissions after LB use. With no readmissions, we suspect the extended half-life provides gradual enough decrease in effect to prevent a rebound pain phenomenon. These preliminary results support that LB can be utilized safely in this subset of spine surgery.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577fa

A157: The Long-term Clinical Efficacy of Single Segment Lumbar 4-5 Fusion and Its Effect on the Lumbar –Pelvis Sagittal Alignment Parameter

Abstract

Introduction:

The effect of lumbar fusion of single segment 4-5 (SL4-5) with lumbar healthy adjacent segments on the Lumbar-Pelvis Sagittal Alignment parameter, radiographic ASD (rASD) and its clinical efficacy was discussed according to lumbar types (Roussouly Type).

Material and Methods:

Between March 2008 and March 2012, 317 patients with lumbar fusion of SL4-5 were collected. 51 cases of them met the inclusion and exclusion criteria (25 males and 26 females, with an average age of 43.45). They were categorized to 4 types according to the types of Roussouly. We compared the VAS, ODI, and JOA scores, and the Lumbar-pelvic parameters, such as pelvic incidence (PI), sacral slope(SS), pelvic tilt (PT), lumbar lordosis (LL), UP arc and intervertebral lordosis of lumbar 4-5(IVA4-5), C7 plumb line /Sacro-femoral distance ratio (C7PL/SFD ratio), of the patients in the preoperative and postoperative and final follow-up. MRI was adopted to evaluate ASD before the surgery, and the UCLA Grading Scale and intervertebral stability criteria of lumbar degeneration were introduced to evaluate ASD after the operation. Changes of the parameters in different periods were statistically analyzed.

Results:

Mean follow-up time was 42.58 months (36 to 67 months). The distribution of patients according to Roussouly types was high proportion: Type II:15 cases (29.42%)and Type III: 20 cases (39.22%).In Type I group: There were significant improvement (P < .01)in LL, UP arc, IVA4-5and SS in Postoperative and final follow-up, compared with that in preoperative, but PT was decreased. In Type II and III: IVA4-5 significantly improvement (P < .05) in the postoperative and final follow-up compared with that in preoperative, the LL in follow-up significantly increased (P < .05) compared with that in preoperative, while the SS, PT, and PI showed no significant differences. In TypeII UP arc was significantly increased in the final follow-up .In Type IV: The IVA4-5 (P < .05) significantly increased with statistically significant differences to the preoperative, but there was no significant difference in LL, UP arc, SS, PT and PI between preoperative and postoperative. The ratio of C7PL/SFD was significantly decreased in the postoperative and final follow-up compared with that in preoperative in all types .Postoperative and follow-up of patients had significant improvement over preoperative in VAS, ODI, JOA scores. The general prevalence of rASD was 17.64% in all patients. Analysis of rASD risk factors found that: Age, follow-up time, PI, IVA4-5 is a major factor.

Conclusion:

SL4-5 can significantly increase IVAL4-5, but have different effects to spine-pelvis Sagittal Alignment parameters according to types of Roussouly. IVA4-5 is a significant risk factor, the greater the age, the longer follow-up time, higher PI values more prone to rASD. The view of select the appropriate intervertebral fusion angle is possible to change the adjacent segment degeneration process, reduce the incidence of rASD and improve patient prognosis.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577fb

A158: Continuous Outcome Monitoring to Improve Quality of Spine Surgery in Patients with Degenerative Lumbar Spine Disorders

Abstract

Introduction:

Systematic and continuous patient-related outcome monitoring is important to assess future value (outcomes relative to cost) of care delivered.1,2 Outcome monitoring through a registry is expected to contribute to quality improvement. A recently performed systematic review showed a lack of evidence that registries had an impact on the quality of spine care.3 To improve the quality of evidence recommendations were presented to improve the underlying methodology; eg, a standardized approach in outcomes registration and a systematic feedback of outcomes of interventions to care professionals.3 Surgical interventions in patients with degenerative lumbar spine disorders are controversial. To improve the institutional quality of surgical care, since May 2012 all new patients are web-based registered (pre-treatment response rate: 97%, n = 6705) and when surgically treated patients are systematically followed over time (global one-year follow-up response rate: 77%). Purpose: to evaluate whether an institutional spine outcome registry could improve the quality of care in surgically treated patients with degenerative lumbar spine disorders.

Material and Methods:

Definition of two surgical cohorts with baseline (T0) and 1-year follow-up (T1) data: decompression surgery (1-level) (T0 n = 71; T1 n = 54) and interbody fusion surgery (1-level) (T0 n = 169); T1 n = 132). Patient-reported outcome measures (PROMs): functional status (ODI), back and leg pain intensity (NRS), health-related quality of life (EQ5D). Relevant patient-related factors (pre-treatment characteristics, surgery-related) and clinician-based outcomes (complications, revision surgeries) are registered. The feedback to professionals is organised in an online and real-time ‘dashboard’ (ie, complications and outcomes, corrected for influencing factors) and related to known norm values (ODI, EQ5D). For each outcome measure the 10 best and 10 worst performing patients are presented. Currently, these patients are studied in a case series design. The results will be discussed trimestral within the surgical team and after consensus actions to improve the care are defined.

Results:

Decompression—The PROMs improved: ODI 41.6 (SD 9.6) to 24.1 (SD 14.1), NRSback 7.2 (SD 0.8) to 3.4 (SD 2.3), NRSleg 4.9 (SD 2.9) to 3.0 (SD 2.9), and EQ5D 0.42 (SD 0.23) to 0.74 (SD 0.10). 2015: post-operative complication rate 17%, revision surgery in 2%. Interbody fusion—The PROMs improved: ODI 43.7 (SD 8.3) to 23.5 (SD 13.5), NRSback 7.1 (SD 1.2) to 3.8 (SD 2.2), NRSleg 5.9 (SD 2.1) to 3.3 (SD 2.7), and EQ5D 0.41 (SD 0.28) to 0.74 (SD 0.10). 2015: post-operative complication rate 12%, revision surgery in 20%.

Conclusion:

Patients in both surgical cohorts improved in relevant outcomes. The support among professionals is high, mainly due to the fact that outcomes are visualised both pooled in the real-time dashboard and individually in the electronic patient file. The one-year follow-up response on PROMs is acceptable.3 Continuous active efforts are needed to improve the response. Currently, the best and worst responders on PROMs of each cohort are studied. The results will be presented at the conference. With these results clinical policy could be improved; eg, through identification of patients with a risk of worse outcomes. This feedback contributes to awareness, peer-to-peer learning and ultimately to improvement of surgical outcomes and value-based spine care.

References

1. Porter M. What is Value in Health Care? N. Engl. J. Med. 2010; 2477–2481.

2. Porter ME, Larsson S, Lee TH. Standardizing Patient Outcomes Measurement. N. Engl. J. Med. 2016; 374, 504–506.

3. van Hooff ML, Jacobs WC, Willems PC et al. Evidence and practice in spine registries. A systematic review, and recommendations for future design of registries. Acta Orthop. 2015; 86(5):534-44.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577fc

A159: Quality of Life in Patients Who Underwent Lumbar Spine Fusion Surgery Compared with Adjusted Normal Italian Population: A Pilot Study

Abstract

Introduction:

There is an increasing interest in patient self-reported outcome measures (PROs) after spine surgery.1 PROs include patients perspective about quality of life and improvement in functional recovery after surgery, and can provide evidence for the efficacy of surgical treatment. The purpose of this study was to assess whether the health-related quality of life reported by patients who underwent lumbar spine fusion surgery for degenerative spinal disorders, at one year, is similar to the normal adjusted Italian population.

Materials and Methods:

Consecutive patients who underwent lumbar decompression and transpedicular instrumentation using pedicle screws and rods at L-S levels in 2015 at the Orthopaedic Department of the University of Ferrara were eligible for the study. The study inclusion criteria were: age 18-85 y, absence of pre-existing cognitive or neurological disease, degenerative spine condition and no previous spinal intervention. The patients who consented completed the Italian validated version of Oswestry Disability Index (ODI)2 and SF-36 questionnaire3, during routine follow-up assessment at one year. For each SF-36 dimension, we computed the normal values for the Italian population matched to our study patients for gender and age (adjusted)4 Pain after surgery, and patient satisfaction with surgery were measured by Numerical Rating Scale (0-100) at one year.

Results:

Of the 45 patients who underwent lumbar spine fusion surgery in 2015, we excluded 12 patients because surgery was due to vertebral fractures, 1 for spine malignancy, and 4 who had any previous surgical intervention for the same disease. One patient had Parkinson’s disease, 4 patients were lost at follow-up and 1 refused the interview. In the 22 patients studied (7 M and 15F, mean age 66±12 y, BMI 28±5) radiological evaluation at the routine follow-up assessments of the vertebral levels fused showed a successful arthrodesis without evidence of pseudoarthrosis. One year after operation, the level of physical function of SF-36 of the study patients was similar to that of the adjusted normal population, and the levels of all the other dimensions of SF-36 of the study patients were slightly better than that of the normal population. According to ODI, 15 patients reported no or minimal disability (range 0-20), five had a moderate disability (range 21-34) and two severe disability (47 and 62, respectively). Median pain score at one year was 2 (Q1-Q3: 1-5). The patients who reported high ODI scores complained of persistent postoperative back and leg pain. In six patients with persistent postoperative pain radiating to the buttock, provocative test for sacroiliac joint involvement as a pain generator were positive. Eighteen out of 22 patients reported a satisfaction with the surgical operation ≥70.

Conclusion:

This is a pilot study on a small number of patients, with a successful arthrodesis at the radiological evaluation. However, the patients showed a quality of life similar to that of the healthy adjusted population. These results differ from those of Pekkanen et al5, who found a patients Physical Component Score worse than that of a Finnish general population sample. These findings need to be confirmed in a large population including patients with previous surgical interventions.

References

1. Norvell D.C., Dettori J.R., Chapman J.R.: Success in Spine Care: the Proof is in the Measurement, Part II. Global Spine J 2015;05(06):455-456.

2. Monticone M., Baiardi P., Ferrari S., Mugnai R., Pilastrini P., Vanti C., Zanoli G.: Development of the italian version of the Oswestry Disability Index (ODI-I): A cross-cultural adaptation, reliability and validity study. Spine 2009 1; 34: 2090-5.

3. Apolone G, Mosconi P. The Italian SF-36 Health Survey: translation, validation and norming. J Clin Epidemiol 1998; 51:1025-36.

4. Apolone G, Mosconi P, Ware J. Il questionario sullo stato di salute SF-36. Manuale d’uso e Guida all’Interpretazione dei Risultati. 1997 Milan, Italy; Guerini Ed Associati.

5. Pekkanen L, Neva MH, Kautianen H, Dekker J, Pitulainen K, Wahlman M, Hakkinen A. Disability and health-related quality of life in patients undergoing spinal fusion: a comparison with a general population sample. BMC Muscoloskeletal Disorders 2013; 14:1-8.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577fd

A160: Comparison of Peri-operative and Short Term Outcomes between Minimally Invasive and Conventional Lumbar Interbody Fusion

Abstract

Objectives:

To identify the difference between minimally invasive thoraco lumbar interbody fusion (MI-TLIF) and conventional lumbar fusion for the peri-operative and 12 month lifestyle outcome measures.

Method:

It was a retrospective secondary data analysis. 36 MI-TLIF patients and 60 conventional surgery patients undergoing single-level lumbar interbody fusion between October 2012 and May 2014 were studied. The peri-operative factors such as duration of surgery, length of hospital stay and peri-operative complications were analysed from patient notes. The 12 month lifestyle measures (pain and discomfort, mobility, anxiety and depression, ability to perform daily tasks, and self-care) were analysed from the patient’s feedbacks via the Euro-Spine Spine Tango forms.

Results:

There was a statistically significant result in favour of MI-TLIF for all the peri-operative measures. The operative time for MI-TLIF patients was 260.44 minutes (±9.95) in comparison to 297.05 minutes (±9.28) for open patients. The mean length of hospital stay for MI-TLIF was 3.25 days (±0.38) in comparison to 6.92 days (±1.13) for open surgery. MI-TLIF patients had fewer complications from surgery in comparison to the conventional surgery group (MI-TLIF 16.7%, Conventional 43.3%, P = .004). The 12 month lifestyle outcome measures also showed similar advantage for MI-TLIF over the conventional surgery in 3 areas; severe pain (open 29%, MI-TLIF 17% P = .039), moderate mobility (open 69%, MI-TLIF 53% P = .011), and severe anxiety (open 14%, MI-TLIF 3% p = 0.034).

Conclusion:

For the measures compared MI-TLIF appears to have an advantage over the single level conventional open surgery at the peri operative and short term follow up periods.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577fe

A161: The Use of Cortical Bone Trajectory Technique in Preventing Implant Loosening in Osteoporotic Spines

Abstract

Introduction:

Cortical bone trajectory (CBT) technique has been revisited in recent years with regard to its use in instrumenting the osteoporotic spine. This is most relevant in current practice where we are witnessing a rising elderly demographic index. We looked at the theoretical forte of this technique -- its effectiveness in preventing implant loosening.

Material and Methods:

From December 2012 till June 2014, 64 adult women underwent lumbar spine decompression and instrumentation using the CBT technique by a single surgeon. They were post-menopausal women with ages ranging from 62 till 92 years old. The surgical indications were for lumbar spine stenosis presenting with radiculopathy. The number of levels operated on ranged from one till four. We excluded patients with metastatic spine disease, infective spine lesions and spondylolisthesis greater than Grade 2. All patients received bi-laminar decompression and 60 had at least one level of interbody fusion. These patients were then followed up for a minimum of 24 months. Of the 64 cases, 3 were lost to follow-up. One patient succumbed to a cerebrovascular event during the follow-up period, another was uncontactable while another declined to be studied. We studied the incidence of loosening with quarterly radiographs in the first year and twice annually in the second, and a CT scan at 12 and 24 months. The films were read and interpreted separately by the author and 2 radiologists, with statistical adjustment of inter-observer variation.

Results:

Five patients suffered screw loosening, 2 of them having it at the sacral level and the remaining, on the cephalad last-instrumented vertebra. Of the 372 screws implanted, 4 sacral and 7 lumbar were loosened. Loosening was detected at time periods ranging from 3 months to 9 month after surgery, and was invariably associated with failure of fusion at that level.

Conclusion:

The rates of loosening in our study compare favourably against loosening rates found in classical pedicle screw constructs. Cortical bone trajectory holds the possibility of preventing implant loosening by virtue of its good cortical purchase. Such a likelihood calls for the audit of a larger series to further validate its results.

Disclosure

The author did not receive funds or benefits in any kind pertaining to this subject during the conduct of this study.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577ff

A162: Correlation between Outcome Measurement Tools in Patients with Lumbar Spine Fusion for Degenerative Disease

Abstract

Introduction:

Degenerative lumbar disc disease is a chronic condition with wide impact over patient’s functional status. Several questionnaires were developed to assess the functional status in patients with chronic low back pain, but the more frequently adopted in published studies are the Oswestry Disability Index (ODI) and the Scoliosis Research Society-22 (SRS-22). The aim of this study is to correlate the different scales of quality of life with each other, trying to determine which individual factors are more decisive for worse or better clinical and functional post-operative outcome.

Material and Methods:

This is a transversal and observational study considering patients who underwent lumbar spine fusion due to degenerative disc disease, who completed a minimum of 12 months postoperative follow-up. The ODI and SRS-22 questionnaires were applied to all patients and the Pearson’s correlation coefficient was calculated between the ODI and the SRS-22 domains.

Results:

61 patients met the inclusion criteria and had data regard the ODI and SRS-22 recorded. 19 were males and 42 females. The mean age of patients was 60.4 years old (19-88 y) and the mean of postoperative follow-up was 29 months (12-67 m). The mean of the questionnaires’ scores were ODI: 43.4 (SD: ±21.7) and SRS-22: 2.74 (SD: ±0.59), while the mean of the SRS-22 domains were Function: 2.66 (SD: ±0.91), Pain: 2.83 (SD: ±0.9), Appearance: 2.64 (SD: ±0.92), Mental 3.03 (SD: ±0.9) and Satisfaction: 3.38 (SD: ±1.15). There was no statistically significant difference in none score between patients gender. The ODI presented inverse significant correlation with SRS-22 total and all domains, except Satisfaction. Significant correlation was also observed between the SRS-22 total and their domains, except between Function.

Conclusion:

Our results reinforce the reliability of the ODI and SRS-22 (Total and their domains) as outcome measurement tools for lumbar spine fusion follow-up. The lack of correlation between ODI and SRS-22 Satisfaction as well as between SRS-22 Function and Satisfaction suggests that the satisfaction with the surgical treatment was independent of the postoperative disability.

Global Spine J. 2017 May; 7(2 Suppl): 2S–189S.
Published online 2017 May 5. doi:  10.1177/2192568217708577fg

A163: Trends and Costs of External Electric Bone Stimulators and Grafting Materials in Anterior Lumbar Interbody Fusion