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1.  Demineralized Bone Matrix, as a Graft Enhancer of Auto-Local Bone in Posterior Lumbar Interbody Fusion 
Asian Spine Journal  2014;8(2):129-137.
Study Design
A case controlled study with prospective data collection.
Purpose
To evaluate the early influence and the final consequence of demineralized bone matrix (DBM) on auto-local bone as a graft enhancer in posterior lumbar interbody fusion (PLIF).
Overview of Literature
DBM is known as an osteoinductive material; however, it has not been clearly recognized to enhance auto-local bone with a small amount.
Methods
Patients who had a PLIF were allocated into two groups. Group I (70 cases) used auto-local bone chips and group II (44 cases) used DBM as an additive to auto-local bone, 1 mL per a segment. Group selection was alternated. Early assessment was performed by computed tomography at 6 months and final assessment was done by simple radiography after 24 months at least. The degree of bone formation was assessed by 4 grade scale.
Results
The subjects of both groups were homogenous and had similar Oswestry Disability Index at final assessment. The ratio of auto-local bone chips and DBM was 6:1. The degree of bone formation at 6 months after surgery was superior in group II. However, there was no significant difference between the two groups at the final assessment.
Conclusions
DBM was not recognized to enhance auto-local bone with small amount.
doi:10.4184/asj.2014.8.2.129
PMCID: PMC3996335  PMID: 24761193
Demineralized bone matrix; Graft enhancer; Posterior lumbar interbody fusion
2.  A Prospective Randomized Clinical Trial Comparing Bone Union Rate Following Anterior Cervical Discectomy and Fusion Using a Polyetheretherketone Cage: Hydroxyapatite/B-Tricalcium Phosphate Mixture versus Hydroxyapatite/Demineralized Bone Matrix Mixture 
Asian Spine Journal  2015;9(1):30-38.
Study Design
Prospective randomized noninferiority trial.
Purpose
To evaluate whether the union rate of anterior cervical discectomy and fusion (ACDF) using a polyetheretherketone (PEEK) cage filled with a mixture of hydroxyapatite (HA) and demineralized bone matrix (DBM) is inferior to that of a mixture of β-tricalcium phosphate (β-TCP) and HA.
Overview of Literature
There have been no clinical trials investigating the outcomes of a mixture of HA and DBM in a PEEK cage in ACDF.
Methods
Eighty-five eligible patients were randomly assigned to group B (n=43), in which a PEEK cage with a mixture of HA and DBM was used, or group C (n=42), in which a PEEK cage with a mixture of HA and β-TCP was used. The primary study endpoint was the fusion rate, which was assessed with dynamic radiographs and computed tomography (CT) scans. Secondary endpoints included pain intensity using a visual analogue scale, functional outcome using a neck disability index score, laboratory tests of inflammatory profiles, and the infection rate.
Results
Seventy-seven patients (38 in group B and 39 in group C) were included in the final analysis. One year postoperatively, bone fusion was achieved in 87% of group B patients and 87% of group C patients on dynamic radiographs, and 87% of group B patients and 72% of group C patients on CT scans (p=1.00 and 0.16, respectively). There were also no between-groups differences with respect to the secondary endpoints.
Conclusions
A HA/DBM mixture inside a PEEK cage can provide noninferior outcomes compared to a HA/TCP mixture in ACDF.
doi:10.4184/asj.2015.9.1.30
PMCID: PMC4330216  PMID: 25705332
Anterior cervical discectomy and fusion; Polyetheretherketone cage; Hydroxyapatites; Demineralized bone matrix; Beta-tricalcium phosphate
3.  End Plate Disproportion and Degenerative Disc Disease: A Case-Control Study 
Asian Spine Journal  2014;8(4):405-411.
Study Design
Case-control.
Purpose
To determine whether a disproportion between two neighboring vertebral end plates is associated with degenerative disc disease.
Overview of Literature
Recently, it has been suggested that disproportion of the end plates of two adjacent vertebrae may increase the risk of disc herniation.
Methods
Magnetic resonance (MR) images (n=160) with evidence of grades I-II lumbar degenerative disc disease (modified Pfirrmann's classification) and normal MR images of the lumbar region (n=160) were reviewed. On midsagittal sections, the difference of anteroposterior diameter of upper and lower end plates neighboring a degenerated (in the case group) or normal (in the control group) intervertebral disc was calculated (difference of end plates [DEP]).
Results
Mean DEP was significantly higher in the case group at the L5-S1 level (2.73±0.23 mm vs. 2.21±0.12 mm, p=0.03). Differences were not statistically significant at L1-L2 (1.31±0.13 mm in the cases vs. 1.28±0.08 mm in the controls, p=0.78), L2-L3 (1.45±0.12 mm in the cases vs. 1.37±0.08 mm in the controls, p=0.58), L3-L4 (1.52±0.13 mm in the cases vs. 1.49±0.10 mm in the controls, p=0.88), and L4-L5 (2.15±0.21 mm in the cases vs. 2.04±0.20 mm in the controls, p=0.31) levels. The difference at the L5-S1 level did not remain significant after adjusting for body mass index (BMI), which was significantly higher in the patients.
Conclusions
End plate disproportion may be a significant, BMI-dependent risk factor for lumbar degenerative disc disease.
doi:10.4184/asj.2014.8.4.405
PMCID: PMC4149982  PMID: 25187856
Vertebra; Anatomy; Intervertebral disc degeneration
4.  Short-Term Results of Transforaminal Lumbar Interbody Fusion Using Pedicle Screw with Cortical Bone Trajectory Compared with Conventional Trajectory 
Asian Spine Journal  2015;9(3):440-448.
Study Design
Case-control study.
Purpose
To evaluate clinical and radiological results of transforaminal lumbar interbody fusion (TLIF) performed with cortical bone trajectory (CBT) pedicle screw insertion with those of TLIF using 'conventional' or percutaneous pedicle screw insertion.
Overview of Literature
CBT is a new trajectory for pedicle screw insertion in the lumbar spine; clinical and radiological results of TLIF using pedicle screws inserted with CBT are unclear.
Methods
In total, 26 patients (11 males, 15 females) were enrolled in this retrospective study and divided into three groups: TLIF with pedicle screw insertion by conventional minimally invasive methods via the Wiltse approach (M-TLIF, n=10), TLIF with percutaneous pedicle screw insertion (P-TLIF, n=6), and TLIF with pedicle screw insertion with CBT (CBT-TLIF, n=10). Surgical results and preand postoperative radiological findings were evaluated and compared.
Results
Intraoperative blood loss was significantly less with CBT-TLIF (p=0.03) than with M-TLIF. Postoperative lordotic angles did not differ significantly among the three groups. Complete fusions were obtained in 10 of 12 levels (83%) with M-TLIF, in seven levels (100%) with P-TLIF, and in 10 of 11 levels (91%) with CBT-TLIF. On postoperative computed tomography, correct positioning was seen in 84.1% of M-TLIF screws, 88.5% of P-TLIF screws, and 90% of CBT-TLIF screws.
Conclusions
CBT-TLIF resulted in less blood loss and a shorter operative duration than M-TLIF or P-TLIF. Postoperative rates of bone union, maintenance of lordotic angles, and accuracy of pedicle screw positions were similar among the three groups.
doi:10.4184/asj.2015.9.3.440
PMCID: PMC4472594  PMID: 26097661
Transforaminal lumbar interbody fusion; Cortical bone trajectory; Conventional trajectory; Percutaneous insertion; Computed tomography
5.  What Is the Effect of Spino-Pelvic Sagittal Parameters and Back Muscles on Osteoporotic Vertebral Fracture? 
Asian Spine Journal  2015;9(2):162-169.
Study Design
Case control study.
Purpose
To examine the effect of spino-pelvic sagittal parameters and back muscles on osteoporotic vertebral fracture.
Overview of Literature
Low bone mass is not the only important component of the risk on osteoporotic vertebral fracture; many other risk factors also contribute to skeletal fragility.
Methods
Seventy-two patients who had a lateral radiograph of the whole spine, magnetic resonance imaging of the lumbar spine, and bone densitometry, were enrolled. The spino-pelvic sagittal parameters (pelvic incidence, pelvic tilt [PT], sacral slope, thoracic kyphosis, lumbar lordosis), age, lumbar bone mineral density, and amount of back muscle around the lumbar spine were analyzed.
Results
There was higher sagittal imbalance of the spine in the vertebral fracture group (p=0.011). In spinopelvic parameters, the average of PT was 22.13° in vertebral fracture group and 13.70° in the non-fracture group (p=0.002). The amount of lower back extensor muscle in the vertebral fracture group was 2,170 mm2, which was lower than the non-fracture group (3,040 mm2, p=0.001). Multiple logistic regression analysis for the risk of osteoporotic vertebral fracture was significant in lumbar bone mineral density (odds ratio [OR], 0.313; 95% confidence interval [CI], 0.139-0.706, p=0.005) and the muscle ratio of extensor back muscle (OR, 0.902; 95% CI, 0.826-0.984; p=0.020).
Conclusions
These results suggest that osteoporotic vertebral fracture could be developed easily by weakness of extensor back muscle in sagittal imbalance of the spine with high pelvic tilt.
doi:10.4184/asj.2015.9.2.162
PMCID: PMC4404528  PMID: 25901225
Vertebral fracture; Osteoporosis; Back muscle; Spino-pelvic sagittal parameter
6.  Analysis of Postoperative Pain at the Anterior Iliac Crest Harvest Site: A Prospective Study of the Intraoperative Local Administration of Ropivacaine 
Asian Spine Journal  2015;9(1):39-46.
Study Design
This was a prospective randomized comparative study.
Purpose
The aim of this study was to objectify donor site-related pain following anterior iliac crest graft harvesting, in patients who have undergone multilevel anterior cervical discectomy and fusion with plating (ACDFP); and to assess the effect of an intraoperative local single injection of ropivacaine on postoperative pain.
Overview of Literature
Multilevel ACDFP can be associated with a high non-union rate. Autogenous iliac bone has been used to increase union rates, although a high incidence of donor site-related pain has been reported.
Methods
Forty consecutive patients who required 3-level or 4-level ACDFP were prospectively assessed for donor site-related pain. Pain levels were assessed daily for five days postoperative using the visual analog scale (VAS). Patients were randomly assigned to group A or B. In group A patients, 7-10 mL of ropivacaine (0.2%) was injected into the iliac crest after iliac crest graft harvesting. Morphine usage via patient controlled analgesia was calculated. At six months postoperative, patient complaints at the harvest site were documented.
Results
Patients were randomly assigned to group A or B. In group A, ropivacaine was locally administered at the site of the iliac crest graft harvest after fascia closure. In group B, no additional treatments were administered. The average patient age in group A was 56±7.6 years, whereas the average age of patients in group B was 52.6±10.4 years. Group A had an average of 0.6±0.7 previous surgeries per patient, whereas group B had an average of 0.8±1.0 previous surgeries per patient. The average number of levels fused in group A was 3.6±0.7, whereas the average number of levels fused in group B was 3.7±0.9 (all p>0.05). In group A, the mean ropivacaine volume administered was 8.4±1.5 mL. No patient complaints regarding chronic pain, were reported six months postoperatively. No complications were encountered from the harvest site, and all patients underwent successful 3-level and 4-level ACDFP. Statistical analysis showed significant differences for VAS on postoperative day 1 (p=0.004) and day 2 (p=0.005).
Conclusions
VAS assessment showed overall moderate perioperative morbidity in terms of donor site-related pain, which was reduced by administering ropivacaine.
doi:10.4184/asj.2015.9.1.39
PMCID: PMC4330217  PMID: 25705333
Spine; Bone grafting; Complications; Local anesthetics; Pain assessment
7.  Mid-Term Results of Computer-Assisted Cervical Pedicle Screw Fixation 
Asian Spine Journal  2014;8(6):759-767.
Study Design
A retrospective study.
Purpose
The present study aimed to evaluate mid-term results of cervical pedicle screw (CPS) fixation for cervical instability.
Overview of Literature
CPS fixation has widely used in the treatment of cervical spinal instability from various causes; however, there are few reports on mid-term surgical results of CPS fixation.
Methods
Record of 19 patients who underwent cervical and/or upper thoracic (C2-T1) pedicle screw fixation for cervical instability was reviewed. The mean observation period was 90.2 months. Evaluated items included Japanese Orthopaedic Association (JOA) score and C2-7 lordotic angle before surgery and at 5 years after surgery. Postoperative computerized tomography was used to determine the accuracy of screw placement. Visual analog scale (VAS) for neck pain and radiological evidence of adjacent segment degeneration (ASD) at the 5-year follow-up were also evaluated.
Results
Mean JOA score was significantly improved from 9.0 points before surgery to 12.8 at 5 years after surgery (p=0.001). The C2-7 lordotic angle of the neutral position improved from 6.4° to 7.8° at 5 years after surgery, but this was not significant. The major perforation rate was 5.0%. There were no clinically significant complications such as vertebral artery injury, spinal cord injury, or nerve root injury caused by any screw perforation. Mean VAS for neck pain was 49.4 at 5 years after surgery. The rate of ASD was 21.1%.
Conclusions
Our mid-term results showed that CPS fixation was useful for treating cervical instability. Severe complications were prevented with the assistance of a computed tomography-based navigation system.
doi:10.4184/asj.2014.8.6.759
PMCID: PMC4278981  PMID: 25558318
Cervical pedicle screw; Cervical instability; Mid-term results; Adjacent segment degeneration
8.  Characteristics of Sagittal Spino-Pelvic Alignment in Japanese Young Adults 
Asian Spine Journal  2014;8(5):599-604.
Study Design
Radiological analysis of normal patterns of sagittal alignment of the spine.
Purpose
This study aimed to clarify the characteristics of normal sagittal spino-pelvic alignment in Asian people.
Overview of Literature
It is known that there are differences in these parameters based on age, gender, and race. In order to properly plan for surgical correction of the spine for Asian patients, it is necessary to understand the normal spino-pelvic alignment parameters for this population.
Methods
This study analyzed 86 Japanese healthy young adult volunteers (48 men and 38 women; age 35.9±11.1 (mean±standard deviation [SD]). The following parameters were measured on lateral standing radiographs of the entire spine: sagittal vertical axis (SVA), horizontal distance between the C7 plumb line and the posterior superior corner of the superior margin of S1, thoracic kyphotic angle (TK), lumbar lordotic angle (LLA), sacral slope (SS), pelvic tilt (PT), and pelvic incidence (PI).
Results
The values (mean±SD) of SVA, TK, LLA, SS, PT, and PI were 8.45±25.7 mm, 27.5±9.6°, 43.4±14.6°, 34.6±7.8°, 13.2±8.2°, and 46.7±8.9°, respectively. The Japanese young adults evaluated in this study tended to have a smaller PI, LLA, TK, and SVA than most Caucasian people. Regarding gender differences, SVA was significantly longer and TK was significantly smaller in men; however, there was no statistically significant difference in LLA, SS, PA, and PI.
Conclusions
Japanese young adults apparently have smaller PI and LLA values than Caucasian people. When making decisions for optimal sagittal spinal alignment, racial differences should be considered.
doi:10.4184/asj.2014.8.5.599
PMCID: PMC4206809  PMID: 25346812
Sagittal alignment; Normal patterns; Adult spine
9.  Investigation of Efficacy of Mitomycin-C, Sodium Hyaluronate and Human Amniotic Fluid in Preventing Epidural Fibrosis and Adhesion Using a Rat Laminectomy Model 
Asian Spine Journal  2013;7(4):253-259.
Study Design
A retrospective study.
Purpose
The aim of this study was to evalute the effects of mitomycin-C, sodium hyaluronate and human amniotic fluid on preventing spinal epidural fibrosis.
Overview of Literature
The role of scar tissue in pain formation is not exactly known, but it is reported that scar tissue causes adhesions between anatomic structures. Intensive fibrotic tissue compresses on anatomic structures and increases the sensitivity of the nerve root for recurrent herniation and lateral spinal stenosis via limiting movements of the root. Also, neuronal atrophy and axonal degeneration occur under scar tissue.
Methods
The study design included 4 groups of rats: group 1 was the control group, groups 2, 3, and 4 receieved antifibrotic agents, mitomycin-C (group 2), sodium hyaluronate (group 3), and human amniotic fluid (group 4). Midline incision for all animals were done on L5 for total laminectomy. Four weeks after the surgery, the rats were sacrificed and specimens were stained with hematoxylin-eosin and photos of the slides were taken for quantitive assesment of the scar tissue.
Results
There was no significant scar tissue in the experimental animals of groups 2, 3, and 4. It was found that there was no significant difference between drug groups, but there was a statistically significant difference between the drug groups and the control group.
Conclusions
This experimental study shows that implantation of mitomycin-C, sodium hyaluronate and human amniotic fluid reduces epidural fibrosis and adhesions after spinal laminectomy in rat models. Further studies in humans are needed to determine the complications of the agents researched.
doi:10.4184/asj.2013.7.4.253
PMCID: PMC3863649  PMID: 24353840
Lumbar spine; Lumbar disc herniation; Lumbar spinal stenosis; Lumbar pain; Epidural fibrosis
10.  Cervical Pedicle Screw Fixation Combined with Laminoplasty for Cervical Spondylotic Myelopathy with Instability 
Asian Spine Journal  2012;6(4):241-248.
Study Design
A retrospective study.
Purpose
To evaluate the surgical results of cervical pedicle screw (CPS) fixation combined with laminoplasty for treating cervical spondylotic myelopathy (CSM) with instability.
Overview of Literature
Cervical fixation and spinal cord decompression are required for CSM patients with instability. However, only a few studies have reported on CPS fixation combined with posterior decompression for unstable CSM patients.
Methods
Thirteen patients that underwent CPS fixation combined with laminoplasty for CSM with instability were evaluated in this study. We assessed the clinical and radiological results of the surgical procedures. The Japanese Orthopedic Association (JOA) scoring system was used to evaluate the clinical results. The percentages of sli p, difference in sli p angle between maximum flexion and maximum extension of unstable intervertebrae, and perforation rate of CPS were evaluated.
Results
The mean JOA scores before surgery, immediately after surgery, and at final follow-up were 9.1, 13.3, and 12.6, respectively. The mean percentages of sli p before surgery, immediately after surgery, and at final follow-up were 9.1%, 3.2%, and 3.5%, respectively; there were significant improvements immediately after surgery and at final follow-up. The difference in sli p angle between the maximum flexion and maximum extension of the unstable intervertebrae changed from 9.0° before surgery to 1.6° at the final follow-up. The perforation rate of CPS was 10.9%.
Conclusions
The results suggest that CPS fixation combined with laminoplasty is an effective surgical procedure for treating CSM with instability.
doi:10.4184/asj.2012.6.4.241
PMCID: PMC3530698  PMID: 23275807
Cervical spondylosis; Myelopathy; Instability; Cervical fixation
11.  Comparison of Kyphoplasty and Lordoplasty in the Treatment of Osteoporotic Vertebral Compression Fracture 
Asian Spine Journal  2010;4(2):102-108.
Study Design
A retrospective study.
Purpose
To compare the level of restoration of the vertebral height, improvement in the wedge and kyphotic angles, and the incidence of complications in osteoporotic compression fracture in patients treated with either kyphoplasty or lordoplasty.
Overview of Literature
Kyphoplasty involves recompression of the vertebral bodies. Recently, a more effective method known as lordoplasty was introduced.
Methods
Between 2004 and 2009, patients with osteoporotic thoracolumbar vertebral compression fractures were treated by either kyphoplasty (n = 24) or lordoplasty (n = 12) using polymethylmethacrylate (PMMA) cement, and the results of the two interventions were compared. A visual analogue scale was used to measure the pain status. Preoperative and postoperative radiographs were analyzed to quantify the anterior vertebral height restoration and the wedge and kyphotic alignment correction.
Results
All patients in both groups reported a significant decrease in pain. The anterior heights increased 24.2% and 17.5% after the lordoplasty and kyphoplasty procedures, respectively (p < 0.05). Three months after the procedures, there was a larger decrease in the loss of anterior vertebral height in the kyphoplasty group (12.8%) than in the lordoplasty group (6.3%, p < 0.05). The wedge angles decreased after both procedures. The wedge angle in the lordoplasty group maintained its value after 3 months (p < 0.05). The kyphotic angular correction was 11.4 and 7.0° in the lordoplasty and kyphoplasty groups, respectively (p < 0.05). Both kyphotic deformities worsened to a similar degree of 5° after 3 months.
Conclusions
Lordoplasty is more useful than kyphoplasty in terms of the improved anatomic restoration and postoperative maintenance.
doi:10.4184/asj.2010.4.2.102
PMCID: PMC2996621  PMID: 21165313
Osteoporotic vertebral compression fracture; Lordoplasty; Vertebroplasty
12.  Evaluation of Role of Anterior Debridement and Decompression of Spinal Cord and Instrumentation in Treatment of Tubercular Spondylitis 
Asian Spine Journal  2012;6(3):183-193.
Study Design
Prospective study with simple randomization.
Purpose
To evaluate the results of anterior spinal instrumentation, debridement and decompression of cord and compare it with results of a similar procedure done without the use of anterior instrumentation.
Overview of Literature
Use of anterior spinal instrumentation in treatment of tubercular spondylitis is still an infrequently followed modality of treatment and data regarding its usefulness are still emerging.
Methods
Thirty-two patients of tubercular paraplegia with involvement of dorsal and dorso-lumbar vertebrae were operated with anterior spinal cord decompression, autofibular strut grafting with anterior instrumentation in 18 patients and no implant in 14 patients. Results were compared on the basis of improvement in Frankel grade, correction of local kyphosis, decrease in canal compromise and further progression of kyphosis.
Results
The mean local kyphosis correction in the immediate postoperative period was 24.1° in the instrumented group and was 6.1° in the non instrumented group. The mean late loss of correction of local kyphosis at 3 years follow-up was 1.7° in the instrumented and 6.7° in the non instrumented group. The mean improvement in canal compression was 39.5% in the instrumented group and 34.8% in the non instrumented group.
Conclusions
In treatment of tubercular spondylitis by anterior debridement and decompression of the spinal cord and autofibular strut grafting, the use of instrumentation has no relation with the improvement in neurological status, however the correction of local kyphosis and prevention of further progression of local kyphosis was better with the use anterior spinal instrumentation.
doi:10.4184/asj.2012.6.3.183
PMCID: PMC3429609  PMID: 22977698
Tuberculosis; Instrumentation; Kyphosis; Paraplegia
13.  Spinal Deformity Correction in Duchenne Muscular Dystrophy (DMD): Comparing the Outcome of Two Instrumentation Techniques 
Asian Spine Journal  2011;5(1):43-50.
Study Design
A retrospective matched cohort study.
Purpose
To compare the results of combined Luque rod-sublaminar wiring (thoracic) and pedicle (lower lumbar) instrumentation (SLW) versus those with pedicle screw fixation (PS) for scoliosis correction in Duchenne muscular dystrophy (DMD).
Overview of Literature
PS fixation is gaining popularity. Two instrumentation systems were not compared before in a matched cohort of patients.
Methods
Two groups of patients with DMD were matched according to the age at surgery, magnitude of deformity and vital capacity. Indications for surgery included loss of sitting balance, rapid decline of vital capacity and curve progression. In group 1 (22 patients) SLW fixation was used from T2/3 to pelvis or sacrum. In group 2 (18 patients) PS fixation was used from T2/3 to L5. Five patients had all level segmental PS fixations. Minimum follow-up was 2 years (range, 2 to 13 years). Radiographs, lung function tests and subjective/objective assessment were performed at standardized intervals.
Results
Mean Cobb angle in group 1 improved from 45.3° (range, 26 to 75°) to 17.7°(range, 0 to 37°) and mean pelvic obliquity improved from 14.5° (range, 8 to 28°) to 5.6° (range, 0 to 15°). Mean Cobb angle in group 2 improved from 42.8° (range, 28 to 80°) to 7.3° (range, 0 to 20°) and mean pelvic obliquity improved from 11.2° (range, 7 to 30°) to 2.0° (range, 0 to 5°) (p < 0.05). Mean operating time and blood loss were less in group 2 (p < 0.05). In group 1, the infection rate and instrumentation failure was higher, and subjective/objective outcomes showed no significant difference between the groups.
Conclusions
PS fixation had superior correction and controlled pelvic obliquity without the need for pelvic fixation.
doi:10.4184/asj.2011.5.1.43
PMCID: PMC3047897  PMID: 21386945
Muscular dystrophy; Duchenne; Spinal deformity; Scoliosis; Pedicle Instrumentation; Sub laminar wiring
14.  Clinical Findings and Results of Surgical Resection in 19 Cases of Spinal Osteoid Osteoma 
Asian Spine Journal  2015;9(3):386-393.
Study Design
Descriptive cases series.
Purpose
To evaluate clinical findings and results of conventional surgery in patients with spinal osteoid osteoma (OO).
Overview of Literature
OO is a rare benign tumor with spinal involvement rate of about 10%-20%.
Methods
This descriptive study was conducted on 19 patients (11 males and 8 females with an average age of 19.8 years) with documented histopathological and imaging findings of OO referred to a university hospital. Neurologic symptoms and pain were scored before and after the open surgical excision. Data were analyzed by SPSS ver. 16 software using chi-square and significance level of 0.05.
Results
The most common complaint was back or neck pain (84.2%) and in 68.4% spinal deformity (mostly scoliosis) shown with an average cobb angle of 21° at presentation. The sites of involvement were 35% in the lumbar, 35% in the thoracic, 25% in the cervical, and 5% in the sacrum. Lamina was the most common site (50%) of involvement with predilection for the right side (p=0.001). All patients were treated by conventional surgical excision with a complete recovery of pain and deformity. No recurrence occurred after a mean follow up of 44.5 months, but 4 of 19 cases instrumented because of induced instability. In one case there were two levels of involvement (C7-T1) simultaneously. Interestingly, 10 out of 19 of our cases belonged to a specific race (Bakhtiari).
Conclusions
Surgical intra-lesional curettage is potentially an effective method without any recurrence, which can lead to spontaneous scoliosis recovery and pain relief. Race may be a potential risk factor for spinal (OO).
doi:10.4184/asj.2015.9.3.386
PMCID: PMC4472586  PMID: 26097653
Osteoid osteoma; Bone tumor; Surgical outcoms; Spine
15.  Risk Factors for Adjacent Segment Disease Development after Lumbar Fusion 
Asian Spine Journal  2015;9(2):239-244.
Study Design
Retrospective cohort study.
Purpose
To identify factors which may be important in the occurrence of symptomatic adjacent segment disease (ASD) after lumbar fusion.
Overview of Literature
Many reports have been published about the risk factors for ASD after lumbar fusion. Despite on the great numbers of risk factors identified for ASD development, study results have been inconsistent and there is controversy regarding which are the most important.
Methods
This study evaluated 120 patients who underwent 360° fusion lumbar surgery from 2007 to 2012. We separated the population into two groups: the first group included 60 patients with long lumbar fusion (three or more levels) and the second group included 60 patients with short lumbar fusion (less than three levels).
Results
In the first group, symptomatic ASD was found in 19 cases during the one year follow-up. There were 14 cases with sagittal imbalance and 5 cases at the incipient stage of disc degeneration according to the preoperative magnetic resonance imaging. At the three year follow-up, symptomatic ASD was diagnosed in 31 cases, of which 17 patients had postoperative sagittal balance disturbance. In the second group, 10 patients had ASD at the one year follow-up. Among these cases, preoperative disc degenerative changes were identified in 8 patients. Sagittal imbalance was found only in 2 cases with symptomatic ASD at the one year follow-up. At the three year follow-up, the number of patients with symptomatic ASD increased to 14. Among them, 13 patients had initial preoperative adjacent disc degenerative changes.
Conclusions
Patients with postoperative sagittal imbalance have a statistically significant increased risk of developing symptomatic ASD due to an overloading the adjacent segments and limited compensatory capacities due to the large number of fixed mobile segments. In the case of a short fixation, preoperative degenerative changes are more important factors in the development of ASD.
doi:10.4184/asj.2015.9.2.239
PMCID: PMC4404539  PMID: 25901236
Fusion; Adjacent segment disease; Sagittal balance
16.  Total Disc Arthroplasty for Treating Lumbar Degenerative Disc Disease 
Asian Spine Journal  2015;9(1):59-64.
Study Design
Lumber disc arthroplasty is a technological advancement that has occurred in the last decade to treat lumbar degenerative disk diseases.
Purpose
The aim of this retrospective study was to establish the impact and outcomes of managing patients with lumbar degenerative disk disease who have been treated with lumbar total disc arthroplasty (TDA).
Overview of Literature
Several studies have shown promising results following this surgery.
Methods
We reviewed the files of 104 patients at the Department of Neurosurgery in Colmar (France) who had been operated on by lumbar spine arthroplasty (Prodisc) between April 2002 and October 2008.
Results
Among the 104 patients, 67 were female and 37 were male with an average age of 33.1 years. We followed the cases for a mean of 20 months. The most frequent level of discopathy was L4-L5 with 62 patients (59.6%) followed by L5-S1 level with 52 patients (50%). Eighty-three patients suffered from low back pain, 21 of which were associated with radiculopathy. The status of 82 patients improved after surgery according to the Oswestry Disability Index score, and 92 patients returned to work.
Conclusions
The results indicate that TDA is a good alternative treatment for lumbar spine disk disease, particularly for patients with disabling and chronic low back pain. This technique contributes to improve living conditions with correct patient selection for surgery.
doi:10.4184/asj.2015.9.1.59
PMCID: PMC4330220  PMID: 25705336
Low back pain; Lumbar vertebrae; Intervertebral disk degeneration
17.  Surgery-Related Complications and Sequelae in Management of Tuberculosis of Spine 
Asian Spine Journal  2014;8(4):435-445.
Study Design
Medical record-based survey.
Purpose
To survey the overall incidence of the intra- and postoperative complications and sequelae, and to propose the preventive measures to reduce complications in the spinal tuberculosis surgery.
Overview of Literature
There is no study focused on the surgery-related complications and sequelae, with some touching lightly on the clinical problems.
Methods
There were 901 patients in this study, including 92 paraplegics. One hundred eighty-six patients had no visible deformity, while those of 715 patients were visible. Six hundred fifty-nine patients had slight to moderate non-rigid kyphosis, and 56 had severe rigid kyphosis. Sixty-seven out of 92 paraplegics had slight to moderate non-rigid kyphosis, and 25 had severe kyphosis. There were 134 cervical and cervicodorsal lesions, 518 thoracic and thoracolumbar lesions, and 249 lumbar and lumbosacral lesions. Seven hundred sixty-four patients had primarily anterior surgeries, and 137 had posterior surgeries. Instrumentation surgery was combined in 174 patients.
Results
There were intra- and postoperative complications: direct large vessel and neurological injuries (cord, roots, nerves), late thrombophlebitis, various thoracic cavity problems, esophagus and ureter injuries, peritoneum perforation, ileus, wound infections, stabilization failure, increase of deformity and late adjacent joint and bone problems. Thrombophlebitis and sympatheticolysis symptoms and signs in the lower limbs were the most common complications related with anterior lumbar and lumbosacral surgeries. Kyphosis increased in 31.5% of the non-instrumented anterior surgery cases (42% in children and 21% in adults).
Conclusions
The safe, effective and most familiar surgical procedure should be adopted to minimize complications and sequelae. Cosmetic spinal surgery should be withheld if functional improvement could not be expected.
doi:10.4184/asj.2014.8.4.435
PMCID: PMC4149986  PMID: 25187860
Tuberculosis; Spine; Therapeutics; Surgery; Complications
18.  Role of Coflex as an Adjunct to Decompression for Symptomatic Lumbar Spinal Stenosis 
Asian Spine Journal  2014;8(2):161-169.
Study Design
Prospective cohort study.
Purpose
To assess whether additional implantation of Coflex following spinal decompression provided better clinical outcomes compared to decompression alone for symptomatic lumbar spinal stenosis (LSS) and to determine whether improvement in clinical outcomes correlated with changes in the radiological indices studied.
Overview of Literature
Literature on benefits of additional Coflex implantation compared to decompression alone for symptomatic LSS is limited.
Methods
Patients with symptomatic LSS who met the study criteria were offered spinal decompression with Coflex implantation. Those patients who accepted Coflex implantation were placed in the Coflex group (n=22); while those opting for decompression alone, were placed in the comparison group (n=24). Clinical outcomes were assessed preoperatively, six-months, one-year and two-years postoperatively, using the Oswestry disability index, 100 mm visual analogue scale (VAS)-back pain and VAS-leg pain, and short form-36 (SF-36). Radiological indices (disc height, foraminal height and sagittal angle) were assessed preoperatively, six months, one year, and two years postoperatively.
Results
Both groups showed statistically significant (p<0.001) improvement in all the clinical outcome indicators at all points in time as compared to the preoperative status. However, improvement in the Coflex group was significantly greater (p<0.001) than the comparison group. Changes in the radiological indices did not correlate significantly with the improvement in clinical outcome indicators.
Conclusions
Additional Coflex implantation after spinal decompression in symptomatic LSS offers better clinical outcomes than decompression alone in the short-term. Changes in radiological indices do not correlate with the improvements in clinical outcomes after surgery for symptomatic LSS.
doi:10.4184/asj.2014.8.2.161
PMCID: PMC3996340  PMID: 24761198
Spinal stenosis; Decompression; Interspinous process device; Coflex
19.  Pedicle Screw Configuration for Thoracolumbar Burst Fracture Treatment: Short versus Long Posterior Fixation Constructs with and without Anterior Column Augmentation 
Asian Spine Journal  2014;8(1):35-43.
Study Design
An in-vitro study.
Purpose
The current study is aimed at investigating the differences in stability between short posterior fixation (SPF), hybrid posterior fixation (HPF), and long posterior fixation (LPF) with and without anterior column augmentation using calcium phosphate bone cement (CaP) for treating burst fractures (BFs).
Overview of Literature
The ideal treatment for thoracolumbar BF is controversial regarding the use of short or LPF constructs.
Methods
Seven human thoracolumbar spines (T9-L4) were tested on a six degree of freedom spine simulator in three physiologic planes, flexion-extension (FE), lateral bending (LB), and axial rotation (AR). Tested surgical constructs included the following: intact, injury (BF), SPF (T12-L2), HPF (T11-L2), LPF (T11-L3), SPF+CaP, HPF+CaP, LPF+CaP, and CaP alone (CaP). Range of motion (ROM) was recorded at T12-L2 in FE, LB, and AR.
Results
The reduction in mean ROM trended as follows: LPF>HPF>SPF. Only LPF constructs and HPF with anterior column augmentation significantly reduced mean ROM in FE and LB compared to the intact state. All instrumented constructs (SPF, HPF, and LPF) significantly reduced ROM in FE and LB compared to the injured condition. Furthermore, the instrumented constructs did not provide significant rotational stability. Injecting CaP provided minimal additional stability.
Conclusions
For the injury created, LPF and HPF provided better stability than SPF with and without anterior column augmentation. Therefore, highly unstable fractures may require extended, long or hybrid fusion constructs for optimum stability.
doi:10.4184/asj.2014.8.1.35
PMCID: PMC3939367  PMID: 24596603
Spine; Fracture fixations; Bone screws; Bone cements
20.  Computer-assisted C1-C2 Transarticular Screw Fixation "Magerl Technique" for Atlantoaxial Instability 
Asian Spine Journal  2012;6(3):168-177.
Study Design
A retrospective study.
Purpose
To evaluate the surgical results of computer-assisted C1-C2 transarticular screw fixation for atlantoaxial instability and the usefulness of the navigation system.
Overview of Literature
We used a computed tomography (CT)-based computer navigation system in planning and screw insertion in Magerl's procedure, which provides the most rigid atlantoaxial fusion, to avoid risk of vertebral artery (VA) tear by avoiding high-riding VA during screw insertion.
Methods
Twenty patients who underwent atlantoaxial fusion under the CT-based navigation system were studied. The mean observation period was 33.5 months. The evaluated items included the existence of VA stenosis by preoperative magnetic resonance angiography, surgical time, blood loss volume, Japanese Orthopaedic Association (JOA) score and Ranawat's pain criteria before surgery and at final follow-up, postoperative screw position evaluated by CT, and bony fusion.
Results
The mean operation time was 205 minutes, with the mean blood loss volume of 242 ml. The mean JOA score was 11.6 points before surgery and 13.7 at final follow-up. Occipital and/or cervical pain presented before operation was remitted or resolved in all patients. Evaluation of screw insertion by CT revealed correct penetration to atlantoaxial joints, with a perforation rate of 2.6%. There was no complication, including VA tear, and all patients who were followed-up during one year or more after surgery achieved bony fusion. Some subjects who appeared inappropriate for surgery from CT images were assessed as eligible for surgery based on the evaluation results obtained using the navigation system.
Conclusions
It was demonstrated that the CT-based navigation system is an effective support device for Magerl's procedure.
doi:10.4184/asj.2012.6.3.168
PMCID: PMC3429607  PMID: 22977696
Atlantoaxial joint; Atlantoaxial instability; CT-based computer navigation system; C1-C2 transarticular screw fixation
21.  The Incidence of Potential Candidates for Total Disc Replacement among Lumbar and Cervical Fusion Patient Populations 
Asian Spine Journal  2011;5(4):213-219.
Study Design
Retrospective chart review.
Purpose
To evaluate the incidence of potential total disc replacement (TDR) candidates among cervical and lumbar fusion patient populations using strict Food and Drug Administration (FDA) criteria and with relative exclusion criteria removed.
Overview of Literature
Recent studies suggest that the potential percentage of patients that are candidates for TDR ranges from 0-5% in lumbar fusions and 43% in cervical fusions.
Methods
We performed a retrospective chart review of 280 consecutive patients who had lumbar (n = 174) and cervical (n = 106) fusion or TDR performed by one of four independent adult orthopaedic spine surgeons. Charts were screened for investigational device exemption (IDE) inclusion/exclusion criteria and later reanalyzed excluding relative exclusion criteria, such as history of chronic medical illness, twolevel disease (cervical cases), and history of prior fusion surgery in the anatomic region.
Results
Of the 174 lumbar surgeries, 10 were TDR with Prodisc-L and 164 were lumbar fusions. The most common TDR exclusion criteria were lytic spondylolisthesis or spinal stenosis (47.7% of patients) and more than 2 level degenerative disc disease (37.9%). 14.9% had no IDE exclusion criteria and would be considered candidates for TDR. After excluding the relative lumbar exclusion criteria, this percentage increased to 25.8%. Of the 106 cervical cases, 3 had a TDR with Prodisc-C and 103 had a cervical fusion. Twenty eight percent had no IDE exclusion criteria and would be considered candidates for cervical TDR.
Conclusions
A larger percentage of cervical fusion candidates are potential candidates for TDR (28%) than lumbar fusion candidates (14.9%) based on the strict IDE criteria.
doi:10.4184/asj.2011.5.4.213
PMCID: PMC3230648  PMID: 22164315
Total disc replacement; Incidence; Inclusion/exclusion criteria; Contraindications; Cervical and lumbar fusions
22.  Ex Vivo Observation of Human Nucleus Pulposus Chondrocytes Isolated From Degenerated Intervertebral Discs 
Asian Spine Journal  2011;5(2):73-81.
Study Design
We performed an ex vivo study to observe cell morphology and viability of human nucleus pulposus (NP) chondrocytes isolated from degenerated intervertebral discs (IVD).
Purpose
To better understand the biological behavior of NP chondrocytes in monolayer cultures.
Overview of Literature
Biological repair of IVDs by cell-based therapy has been shown to be feasible in clinical trials. As one of the most promising transplanting seeds, how the isolated NP chondrocytes behavior ex vivo has not been fully understood.
Methods
Human NP chondrocytes were harvested from 20 degenerated IVDs and cultured in monolayers. Histological and immunochemistry staining was used to detect cell morphology change. Cell viability was studied by analyzing cell cycle distribution and apoptotic rate in the primary and subculuted cells.
Results
The round or polygonal primary NP chondrocytes had an average adherence time of 7 days and took nearly 31 days to reach 95% confluence. The spindle-shaped P1 NP chondrocytes increased growth kinetics and took about 12 hours to adhere and 6.6 days to get 95% confluent. Immunochemistry staining of collagen II was positive in the cell cytoplasm. Nearly 90% of the confluent NP chondrocytes stayed in G1 phase while 16% underwent apoptosis. No significant difference of the collagen II expression, cell cycle distribution or the apoptosis indices were detected between the primary and subcultured NP chondrocytes.
Conclusions
Human NP chondrocytes undergo significant morphological change in monolayer cultures. Cell cycle distribution pattern and apoptosis index of the cutured NP chondrocytes potentially influence their clinical transplantation or laboratory use.
doi:10.4184/asj.2011.5.2.73
PMCID: PMC3095805  PMID: 21629481
Nucleus pulposus; Monolayer culture; Cell cycle; Apoptosis; Growth kinetics
23.  Treatment Outcome of Cervical Tear Drop Fracture 
Asian Spine Journal  2009;3(2):73-79.
Study Design
This is a retrospective study.
Purpose
We wanted to evaluate the clinical results of surgical and conservative treatment for cervical tear drop fracture.
Overview of Literature
The tear drop fracture of the lower cervical spine is generally associated with a high incidence of neurological deficits and surgery is needed to treat this injury. Tear drop fracture of C2 is usually a stable fracture that is amendable to conservative treatment.
Methods
We reviewed the outcomes of 25 patients. Cervical tear drop fracture was classified as the extension and flexion types according to the mechanism of injury. The neurologic symptoms were evaluated by the Frankel classification system, and the loss of lordosis and disc height, and the duration of bony union were analyzed.
Results
Twenty one patients had the flexion type injury and 4 patients had the extension type injury. All the patients with the flexion type were treated by anterior decompression and plate stabilization. All the patients with the extension type were treated conservatively. Ten patients with the flexion type had neurologic deficits. The nerve root injuries recovered fully and the incomplete injuries had an average 1.5 grade recovery. Radiologically, the extension type fracture showed bony union at an average of 12.8 weeks. For the patients with the flexion type fracture, the loss of lordosis was 2.6° and the loss of disc height was 2.1 mm. The period of bony union in 20 cases was 13.0 weeks.
Conclusions
Anterior plate stabilization was an effective treatment for the flexion type tear drop fracture. Conservative treatment is thought to be one of the good clinical methods for treating the extension type tear drop fracture.
doi:10.4184/asj.2009.3.2.73
PMCID: PMC2852077  PMID: 20404951
Cervical spine; Tear drop fracture; Anterior plate stabilization
24.  Radiological Outcome of Short Segment Posterior Instrumentation and Fusion for Thoracolumbar Burst Fractures 
Asian Spine Journal  2015;9(3):427-432.
Study Design
Retrospective study.
Purpose
To evaluate the radiological outcome of the surgical treatment of thoracolumbar burst fractures by using short segment posterior instrumentation (SSPI) and fusion.
Overview of Literature
The optimal surgical treatment of thoracolumbar burst fractures remains a matter of debate. SSPI is one of a number of possible choices, yet some studies have revealed high rates of poor radiological outcome for this SSPI.
Methods
Patients treated using the short segment instrumentation and fusion technique at the Spinal Injuries Center (Iizuka, Fukuoka, Japan) from January 1, 2006 to July 31, 2012 were selected for this study. Radiographic parameters such as local sagittal angle, regional sagittal angle, disc angle, anterior or posterior height of the vertebral body at admission, postoperation and final observation were collected for radiological outcome evaluation.
Results
There were 31 patients who met the inclusion criteria with a mean follow-up duration of 22.7 months (range, 12-48 months). The mean age of this group was 47.9 years (range, 15-77 years). The mean local sagittal angles at the time of admission, post-operation and final observation were 13.1°, 7.8° and 14.8°, respectively. There were 71% good cases and 29% poor cases based on our criteria for the radiological outcome evaluation. The correction loss has a strong correlation with the load sharing classification score (Spearman rho=0.64, p<0.001).
Conclusions
The loss of kyphotic correction following the surgical treatment of thoracolumbar burst fracture by short segment instrumentation is common and has a close correlation with the degree of comminution of the vertebral body. Patients with high load sharing scores are more susceptible to correction loss and postoperative kyphotic deformity than those with low scores.
doi:10.4184/asj.2015.9.3.427
PMCID: PMC4472592  PMID: 26097659
Short segment instrumentation; Thoracolumbar burst fractures; Correction loss; Degree of comminution; Load sharing classification
25.  Accuracy of Free Hand Pedicle Screw Installation in the Thoracic and Lumbar Spine by a Young Surgeon: An Analysis of the First Consecutive 306 Screws Using Computed Tomography 
Asian Spine Journal  2014;8(3):237-243.
Study Design
A retrospective cross-sectional study.
Purpose
The purpose of this study is to evaluate the accuracy and safety of free-hand pedicle screw insertion performed by a young surgeon.
Overview of Literature
Few articles exist regarding the safety of the free-hand technique without inspection by an experienced spine surgeon.
Methods
The index surgeon has performed spinal surgery for 2 years by himself. He performed fluoroscopy-assisted pedicle screw installation for his first year. Since then, he has used the free-hand technique. We retrospectively reviewed the records of all consecutive patients undergoing pedicle screw installation using the free-hand technique without fluoroscopy in the thoracic or lumbar spine by the index surgeon. Incidence and extent of cortical breach by misplaced pedicle screw was determined by a review of postoperative computed tomography (CT) images.
Results
A total of 36 patients received 306 free-hand placed pedicle screws in the thoracic or lumbar spine. A total of 12 screws (3.9%) were identified as breaching the pedicle in 9 patients. Upper thoracic spine was the most frequent location of screw breach (10.8%). Lateral breach (2.3%) was more frequent than any other direction. Screw breach on the right side (9 patients) was more common than that on the left side (3 patients) (p<0.01).
Conclusions
An analysis by CT scan shows that young spine surgeons who have trained under the supervision of an experienced surgeon can safely place free-hand pedicle screws with an acceptable breach rate through repetitive confirmatory steps.
doi:10.4184/asj.2014.8.3.237
PMCID: PMC4068842  PMID: 24967036
Pedicle screw; Thoracic; Lumbar: Free hand; Accuracy; Safety

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