The conventional open pedicle screw fusion (PSF) requires an extensive detachment of the paraspinal muscle from the posterior aspect of the lumbar spine, which can cause muscle injury and subsequently lead to “approach-related morbidity”. The spinous process-splitting (SPS) approach for decompression, unilateral laminotomy for bilateral decompression, and the Wiltse approach for pedicle screw insertion are considered to be less invasive to the paraspinal musculature. We investigated whether SPS open PSF combined with the abovementioned techniques attenuates the paraspinal muscle damage and yields favorable clinical results, including alleviation in the low back discomfort, in comparison to the conventional open PSF.
We studied 53 patients who underwent single-level PSF for the treatment of degenerative spondylolisthesis (27 patients underwent SPS open PSF and the other 26 underwent the conventional open PSF). The clinical outcomes were assessed using the Japanese Orthopedic Association (JOA) score, the Roland–Morris disability questionnaire (RDQ), and the visual analog scale (VAS) for low back pain and low back discomfort (heavy feeling or stiffness). Postoperative multifidus (MF) atrophy was evaluated using MRI. Follow-up examinations were performed at 1 and 3 years after the surgery.
Although there was no significant difference in the JOA and RDQ score between the two groups, the VAS score for low back pain and discomfort after the surgery were significantly lower in the SPS open PSF group than in the conventional open PSF group. The extent of MF atrophy after SPS open PSF was reduced more significantly than after the conventional open PSF during the follow-up. The MF atrophy ratio was found to correlate with low back discomfort at the 1-year follow-up examination.
In conclusion, SPS open PSF was less damaging to the paraspinal muscle than the conventional open PSF and had a significant clinical effect, reducing low back discomfort over 1 year after the surgery.
Posterior lumbar fusion; Multifidus muscle; Wiltse approach; Minimally invasive; Conventionally open
There are technical limitations of multi-level posterior pedicle screw fixation performed by the percutaneous technique. The purpose of this study was to describe the surgical technique and outcome of minimally invasive multi-level posterior lumbar interbody fusion (PLIF) and to determine its efficacy.
Forty-two patients who underwent mini-open PLIF using the percutaneous screw fixation system were studied. The mean age of the patients was 59.1 (range, 23 to 78 years). Two levels were involved in 32 cases and three levels in 10 cases. The clinical outcome was assessed using the visual analog scale (VAS) and Low Back Outcome Score (LBOS). Achievement of radiological fusion, intra-operative blood loss, the midline surgical scar and procedure related complications were also analyzed.
The mean follow-up period was 25.3 months. The mean LBOS prior to surgery was 34.5, which was improved to 49.1 at the final follow up. The mean pain score (VAS) prior to surgery was 7.5 and it was decreased to 2.9 at the last follow up. The mean estimated blood loss was 238 mL (140-350) for the two level procedures and 387 mL (278-458) for three levels. The midline surgical scar was 6.27 cm for two levels and 8.25 cm for three level procedures. Complications included two cases of asymptomatic medial penetration of the pedicle border. However, there were no signs of neurological deterioration or fusion failure.
Multi-level, minimally invasive PLIF can be performed effectively using the percutaneous transpedicular screw fixation system. It can be an alternative to the traditional open procedures.
Posterior lumbar interbody fusion; Percutaneous; Minimally invasive surgery
In this study, we compared the paramedian interfascial approach (PIA) and the traditional midline approach (MA) for lumbar fusion to determine which approach resulted in the least amount of postoperative back muscle atrophy. We performed unilateral transforaminal posterior lumbar interbody fusion via MA on the symptomatic side and pedicle screw fixation via PIA on the other side in the same patient. We evaluated the damage to the paraspinal muscle after MA and PIA by measuring the preoperative and postoperative paraspinal muscle volume in 26 patients. The preoperative and postoperative cross-sectional area, thickness, and width of the multifidus muscle were measured by computed tomography. The degree of postoperative paraspinal muscle atrophy was significantly greater on the MA side than on the contralateral PIA side (-20.7% and -4.8%, respectively, p<0.01). In conclusion, the PIA for lumbar fusion yielded successful outcomes for the preservation of paraspinal muscle in these 26 patients. We suggest that the success of PIA is due to less manipulation and retraction of the paraspinal muscle and further studies on this technique may help confirm whether less muscle injury has positive effects on the long-term clinical outcome.
Paraspinal Muscle; Paramedian Approach; Muscle Atrophy; Lumbar Spine
Transpedicular screw fixation has some disadvantages such as postoperative back pain through wide muscle dissection, long operative time, and cephalad adjacent segmental degeneration (ASD). The purposes of this study are investigation and comparison of radiological and clinical results between interspinous fusion device (IFD) and pedicle screw.
From Jan. 2008 to Aug. 2009, 40 patients underwent spinal fusion with IFD combined with posterior lumbar interbody fusion (PLIF). In same study period, 36 patients underwent spinal fusion with pedicle screw fixation as control group. Dynamic lateral radiographs, visual analogue scale (VAS), and Korean version of the Oswestry disability index (K-ODI) scores were evaluated in both groups.
The lumbar spine diseases in the IFD group were as followings; spinal stenosis in 26, degenerative spondylolisthesis in 12, and intervertebral disc herniation in 2. The mean follow up period was 14.24 months (range; 12 to 22 months) in the IFD group and 18.3 months (range; 12 to 28 months) in pedicle screw group. The mean VAS scores was preoperatively 7.16±2.1 and 8.03±2.3 in the IFD and pedicle screw groups, respectively, and improved postoperatively to 1.3±2.9 and 1.2±3.2 in 1-year follow ups (p<0.05). The K-ODI was decreased significantly in an equal amount in both groups one year postoperatively (p<0.05). The statistics revealed a higher incidence of ASD in pedicle screw group than the IFD group (p=0.029).
Posterior IFD has several advantages over the pedicle screw fixation in terms of skin incision, muscle dissection and short operative time and less intraoperative estimated blood loss. The IFD with PLIF may be a favorable technique to replace the pedicle screw fixation in selective case.
Degenerative; Fusion device; Interspinous; Lumbar disease; Posterior; Adjacent segmental degeneration
In this prospective study, our aim was to compare the clinical outcome of posterior lumbar interbody fusion (PLIF) and posterolateral fusion (PLF) in spondylolisthesis. A total of 138 patients with spondylolisthesis were randomly assigned to two groups: those operated on with pedicle screw fixation and posterior lumbar interbody fusion by autografting (PLIF), and those operated on with pedicle screw fixation and posterolateral fusion by autografting (PLF). The patients were followed-up for four years. Clinical evaluation was carried out using the Oswestry disability index (ODI) and pain index (VAS). Radiography was performed preoperatively and postoperatively to assess the fusion. Both surgical procedures were effective, but the PLF group showed more complications related to hardware biomechanics. There was no significant statistical difference in clinical and functional outcome in the two groups. The PLIF group presented a better fusion rate than the PLF group.
This study is to compare the therapeutic effect of posterior lumbar interbody fusion (PLIF) and transforaminal lumbar interbody fusion (TLIF) with pedicle screw fixation on treatment in adult degenerative spondylolisthesis. A retrospective analysis of 187 patients to compare the complications and associated predictive factors of the two techniques of one level lumbar fusion. Ninety-one had PLIF with two cages and pedicle fixation (group 1), and ninety-six had TLIF with one cage and pedicle fixation (group 2). The two groups had similar age and sex distribution, and level of pain. Inclusion criteria and outcome measurements were identical in both groups. The two groups were operated on with autograft and cage with pedicle fixation. Before surgery and at the 2-year follow-up, pain (VAS) and functional disability (JOA) were quantified. The results showed there were no intraoperative deaths in our study. In the end 176 cases had 2-year follow-up while 11 cases were lost to follow-up. The follow-up rate was 93.4% (85/91) in the PLIF group and 94.8% (91/96) in the TLIF group. All patients had bone fusion, and there were no cases of cage extrusion. The pain index improved from 7.08 ± 1.13 to 2.84 ± 0.89 in PLIF patients and improved from 7.18 ± 1.09 to 2.84 ± 0.91 in TLIF patients (P < 0.001). There were 42 cases of excellent, 29 cases of good, 11 cases of general, and 3 cases of poor results in PLIF group. There were 46 cases of excellent, 31 case of good, 12 case of general, and 2 cases of poor results in TLIF group. The JOA score in all patients was 84.1% of good or excellent (83.5% in PLIF and 84.6% in TLIF, P > 0.05). The average preoperative slip was 30.1 ± 7.2% in PLIF group while in the TLIF it was 31.4 ± 8.3%. Immediately post operatively it was reduced to 7.3 ± 2.1% and 7.4 ± 2.7% and at last F/U it was 8.1 ± 2.8% and 8.2 ± 2.6%, respectively. The average of reduction rate was 75.2 ± 6.4% in PLIF and 75.4 ± 6.2 in TLIF on the initial post operatively X-ray, and 72.6 ± 5.2% and 72.4 ± 5.4% on the follow-up. The percentage rate, reduction rate and lost of reduction rate between the two groups was similar (P > 0.05). The average pre operative disk and foramen height in the PLIF group improved from 6.8 ± 2.3 and 14.2 ± 1.7 preoperatively to 11.6 ± 1.5 and 18.7 ± 1.8 post operatively, respectively. At last follow up there was minimal lost of correction down to 11.24 ± 1.2 and 18.1 ± 1.8, respectively. Similarly in the TLIF group, pre operative disk and foramen height were improved from 6.7 ± 1.7 and 14.1 ± 1.8 to 11.4 ± 1.6 and 18.5 ± 1.6 immediately post operative. At last follow up minimal lost of correction was noted with average disc height of 11.3 ± 1.4 and 18.2 ± 1.7. Both techniques achieve statistical significance in restoration of disc and foraminal (P < 0.01); however, there was no statistical difference between the two techniques. In conclusion, interbody fusion with either a PLIF technique or a TLIF technique provides good outcomes in the treatment of adult degenerative spondylolisthesis. The TLIF procedure is simpler and is as safe and effective as the PLIF technique.
Spondyolisthesis; Interverterbral fusion; Internal fixation
spondylolisthesis is a condition in which a vertebra slips out of the proper position onto the bone below it as a result of pars interarticularis defect. The slipped segment produces abnormal positioning of the vertebrae in relation to each other along the spinal column and causes mechanical back pain and neural breach.
Materials and methods
A randomized and double blinded study consisted of 41 patients aged 36-69 years (18 females and 28 males) treated for symptomatic spondylolisthesis between December,2006 and December, 2009. All patients were randomly distributed into two groups I and II. Twenty patients were in Group I; they underwent reduction of the slipped vertebrae by using Reduction-Screw Technique and posterior lumbar interbody fixation (PLIF). Group II consisted of twenty one patients who underwent only surgical fixation (PLIF) without reduction. All patients in this study had same pre and post operative management.
only one case had broken rod in group I that required revision. Superficial wound infection was experienced in two patients and one patient, from group II, developed wound hematoma. The outcome in both groups was variable on the short term but was almost the same on the long term follow up.
surgical management of symptomatic low grade spondylolisthesis should include neural decompression and surgical fixation. Reduction of slipped vertebral bodies is unnecessary as the ultimate outcome will be likely similar.
spondylolisthesis; surgical fixation; reduction; outcome; neural decompression; ODI
Degenerative lumbar spinal stenosis (DLSS) has become increasingly common and is characterized by multilevel disc herniation and lumbar spondylolisthesis, which are difficult to treat. The current study aimed to evaluate the short-term clinical outcomes and value of the combined use of microendoscopic discectomy (MED) and minimally invasive transforaminal lumbar interbody fusion (MI-TLIF) for the treatment of multilevel DLSS with spondylolisthesis, and to compare the combination with traditional posterior lumbar interbody fusion (PLIF). A total of 26 patients with multilevel DLSS and spondylolisthesis underwent combined MED and MI-TLIF surgery using a single cage and pedicle rod-screw system. These cases were compared with 27 patients who underwent traditional PLIF surgery during the same period. Data concerning incision length, surgery time, blood loss, time of bed rest and Oswestry Disability Index (ODI) score prior to and following surgery were analyzed statistically. Statistical significance was reached in terms of incision length, blood loss and the time of bed rest following surgery (P<0.05), but there was no significant difference between the surgery time and ODI scores of the two groups. The combined use of MED and MI-TLIF has the advantages of reduced blood loss, less damage to the paraspinal soft tissue, shorter length of incision, shorter bed rest time, improved outcomes and shorter recovery times and has similar short-term clinical outcomes to traditional PLIF.
microendoscopic discectomy; minimally invasive transforaminal lumbar interbody fusion; posterior lumbar interbody fusion; lumbar spinal stenosis; lumbar spondylolisthesis
The aim of the study was to evaluate clinical and radiographic outcome of patients treated with a modified Grob technique analysing the advantages related to increased mechanical stability.
30 patients that underwent “in situ” fusion for L5-S1 spondylolisthesis were evaluated. All patients presented a low-dysplastic developmental L5-S1 spondylolisthesis. Patients were divided into two groups: A, in which L5-S1 pedicle instrumentation associated with transsacral screw fixation was performed, and B, in which L5-S1 pedicle instrumentation associated with a posterolateral interbody fusion (PLIF) was performed.
Patients treated with transdiscal L5-S1 fixation observed a faster resolution of the symptoms and a more rapid return to daily activities, especially at 3–6 months’ follow-up. The technique is reliable in giving an optimal mechanical stability to obtain a solid fusion.
The advantages of this technique are lower incidence of neurologic complications, speed of execution and faster return to normal life.
Spondylolisthesis; Surgical technique; Fusion; Back pain; Radicular pain
The original description of the paraspinal posterior approach to the lumbar spine was for spinal fusion, especially regarding lumbosacral spondylolisthesis treatment. In spite of the technical details described by Wiltse, exact location of the area where the sacrospinalis muscle has to be split remains somewhat unclear. The goal of this study was to provide topographic landmarks to facilitate this surgical approach. Thirty cadavers were dissected in order to precisely describe the anatomy of the trans-muscular paraspinal approach. The level of the natural cleavage plane between the multifidus and the longissimus part of the sacrospinalis muscle was noted and measurements were done between this level and the midline at the level of the spinous process of L4. A natural cleavage plane between the multifidus and the longissimus part of the sacrospinalis muscle was present in all cases. There was a fibrous separation between the two muscular parts in 55 out of 60 cases. The mean distance between the level of the cleavage plane and the midline was 4 cm (2.4–5.5 cm). In all cases, small arteries and veins were present, precisely at the level of the cleavage plane. We found it possible to easily localize the anatomical cleavage plane between the multifidus part and the longissimus part of the sacrospinalis muscle. First the superficial muscular fascia is opened near the midline, exposing the posterior aspect of the sacrospinalis muscle. Then, the location of the muscular cleft can be found by identifying the perforating vessels leaving the anatomical inter-muscular space.
Paraspinal approach; Lumbar spine; Lumbosacral spondylolisthesis; Sacrospinalis muscle; Minimally invasive approach
In order to minimize perioperative invasiveness and improve the patients’ functional capacity of daily living, we have performed minimally invasive lumbar decompression and posterolateral fusion (MIS-PLF) with percutaneous pedicle screw fixation for degenerative spondylolisthesis with spinal stenosis. Although several minimally invasive fusion procedures have been reported, no study has yet demonstrated the efficacy of MIS-PLF in degenerative spondylolisthesis of the lumbar spine. This study prospectively compared the mid-term clinical outcome of MIS-PLF with those of conventional PLF (open-PLF) focusing on perioperative invasiveness and patients’ functional capacity of daily living.
Materials and methods
A total of 80 patients received single-level PLF for lumbar degenerative spondylolisthesis with spinal stenosis. There were 43 cases of MIS-PLF and 37 cases of open-PLF. The surgical technique of MIS-PLF included making a main incision (4 cm), and neural decompression followed by percutaneous pedicle screwing and rod insertion. The posterolateral gutter including the medial transverse process was decorticated and iliac bone graft was performed. The parameters analyzed up to a 2-year period included the operation time, intra and postoperative blood loss, Oswestry-Disability Index (ODI), Roland-Morris Questionnaire (RMQ), the Japanese Orthopaedic Association score, and the visual analogue scale of low back pain. The fusion rate and complications were also reviewed.
The average operation time was statistically equivalent between the two groups. The intraoperative blood loss was significantly less in the MIS-PLF group (181 ml) when compared to the open-PLF group (453 ml). The postoperative bleeding on day 1 was also less in the MIS-PLF group (210 ml) when compared to the open-PLF group (406 ml). The ODI and RMQ scores rapidly decreased during the initial postoperative 2 weeks in the MIS-PLF group, and consistently maintained lower values than those in the open-PLF group at 3, 6, 12, and 24 months postoperatively. The fusion rate was statistically equivalent between the two groups (98 vs. 100%), and no major complications occurred.
The MIS-PLF utilizing a percutaneous pedicle screw system is less invasive compared to conventional open-PLF. The reduction in postoperative pain led to an increase in activity of daily living (ADL), demonstrating rapid improvement of several functional parameters. This superiority in the MIS-PLF group was maintained until 2 years postoperatively, suggesting that less invasive PLF offers better mid-term results in terms of reducing low back pain and improving patients’ functional capacity of daily living. The MIS-PLF utilizing percutaneous pedicle screw fixation serves as an alternative technique, eliminating the need for conventional open approach.
Minimally invasive spine surgery; Posterolateral fusion; Percutaneous pedicle screw; Degenerative spondylolisthesis; Lumbar spine
This is a retrospective case series to evaluate clinical variables, complications and outcome of 50 patients who underwent anterior lumbar interbody fusion (ALIF) supplemented with posterior percutaneous pedicle screw fixation for degenerative conditions of the lumbar spine. Twenty-four patients underwent single-level fusion and 26 patients had a two-level fusion for a total of 76 levels fused. The mean lengths of the anterior and posterior (including repositioning) portions of the procedure were 131 and 102 min, respectively. The mean estimated blood loss for the entire procedure was 288 ml. The overall adverse event rate was 12%. The mean VAS score for leg pain, VAS score for back pain and mean ODI all improved postoperatively. This study found that ALIF using allograft bone and rhBMP-2 combined with percutaneous pedicle screw fixation had a high fusion rate and a low incidence of perioperative complications. Patient outcomes showed significant improvements in back and leg pain and physical functioning.
Lumbar arthrodesis; Anterior lumbar interbody fusion (ALIF); Percutaneous pedicle screw fixation
Traditional surgical management of lumbosacral spondylolisthesis is technically challenging and is associated with significant complications. The advent of minimally invasive surgical techniques offers patients treatment alternatives with lower operative morbidity risk. The combination of percutaneous pedicle screw reduction and an axial presacral approach for lumbosacral discectomy and fusion offers an alternative procedure for the surgical management of low-grade lumbosacral spondylolisthesis.
Three patients who had L5-S1 grade 2 spondylolisthesis and who presented with axial pain and lumbar radiculopathy were treated with a minimally invasive surgical technique. The patients-a 51-year-old woman and two men (ages 46 and 50)-were Caucasian. Under fluoroscopic guidance, spondylolisthesis was reduced with a percutaneous pedicle screw system, resulting in interspace distraction. Then, an axial presacral approach with the AxiaLIF System (TranS1, Inc., Wilmington, NC, USA) was used to perform the discectomy and anterior fixation. Once the axial rod was engaged in the L5 vertebral body, further distraction of the spinal interspace was made possible by partially loosening the pedicle screw caps, advancing the AxiaLIF rod to its final position in the vertebrae, and retightening the screw caps. The operative time ranged from 173 to 323 minutes, and blood loss was minimal (50 mL). Indirect foraminal decompression and adequate fixation were achieved in all cases. All patients were ambulatory after surgery and reported relief from pain and resolution of radicular symptoms. No perioperative complications were reported, and patients were discharged in two to three days. Fusion was demonstrated radiographically in all patients at one-year follow-up.
Percutaneous pedicle screw reduction combined with axial presacral lumbar interbody fusion offers a promising and minimally invasive alternative for the management of lumbosacral spondylolisthesis.
The results of posterolateral screw fixation using the Buck technique performed on 24 patients with painful isthmic spondylolysis and up to grade I spondylolisthesis in the lumbar spine are reported. The average age at operation was 29 years and average follow-up was 5 years with a range of 13 months to 12 years. Operations were performed for persistent disabling low back pain. At review 21 patients were either free of pain or complained of only occasional backache and discomfort. All but two patients were satisfied with the operation and rated the result as excellent or good. It is concluded that Buck screw fixation is a safe and reliable method of treatment for painful Grade I spondylolisthesis due to isthmic spondylolysis in the young active adult with a low complication rate.
Paraspinal muscle damage is inevitable during conventional posterior lumbar fusion surgery. Minimal invasive surgery is postulated to result in less muscle damage and better outcome. The aim of this study was to monitor metabolic changes of the paraspinal muscle and to evaluate paraspinal muscle damage during surgery using microdialysis (MD). The basic interstitial metabolisms of the paraspinal muscle and the deltoid muscle were monitored using the MD technique in eight patients, who underwent posterior lumbar fusion surgery (six male and two female, median age 57.7 years, range 37–74) and eight healthy individuals for different positions (five male and three female, age 24.1 ± 0.8 years). Concentrations of glucose, glycerol, and lactate pyruvate ratio (L/P) in both tissues were compared. In the healthy group, the glucose and glycerol concentrations and L/P were unchanged in the paraspinal muscle when the body position changed from prone to supine. The glucose concentration and L/P were stable in the paraspinal muscle during the surgery. Glycerol concentrations increased significantly to 243.0 ± 144.1 μM in the paraspinal muscle and 118.9 ± 79.8 μM in the deltoid muscle in the surgery group. Mean glycerol concentration difference (GCD) between the paraspinal muscle and the deltoid tissue was 124.1 μM (P = 0.003, with 95% confidence interval 83.4–164.9 μM). The key metabolism of paraspinal muscle can be monitored by MD during the conventional posterior lumbar fusion surgery. The glycerol concentration in the paraspinal muscle is markedly increased compared with the deltoid muscle during the surgery. It is proposed that GCD can be used to evaluate surgery related paraspinal muscle damage. Changing body position did not affect the paraspinal muscle metabolism in the healthy subjects.
Glucose; Lactate pyruvate ratio; Glycerol; Paraspinal muscle; Microdialysis
Percutaneous techniques may be helpful to reduce approach-related morbidity of conventional open surgery. The aim of the study was to evaluate the feasibility and safety of mini-open posterior lumbar interbody fusion for instabilities and degenerative disc diseases. From May 2005 until October 2008, 20 patients affected by monosegmental instability and disc herniation underwent mini-open lumbar interbody fusion combined with percutaneous pedicle screw fixation of the lumbar spine. Clinical outcome was assessed using the Visual Analog Scale, Oswestry Disability Index, and Short Form Health Survey-36. The mean follow-up was 24 months. The mean estimated blood loss was 126 ml; the mean length of stay was 5.3 days; the mean operative time was 171 min. At 24-month follow-up, the mean VAS score was 2.1, mean ODI was 27.1%, and mean SF-36 was 85.2%. 80 screws were implanted in 20 patients. 74 screws showed very good position, 5 screws acceptable, and 1 screw unacceptable. A solid fusion was achieved in 17 patients (85%). In our opinion, mini-open TLIF is a valid and safe treatment of lumbar instability and degenerative disc diseases in order to obtain faster return to daily activities.
Percutaneous pedicle screw; Minimally invasive fusion; Disc herniation
Opinions have varied regarding the optimal treatment of an unstable Hangman’s fracture. C2 pedicle screw instrumentation is a biomechanically strong fixation which although done through a simple posterior approach, is a technically demanding procedure. This prospective, non-randomized multicentre study included 15 consecutive patients with displaced type II traumatic spondylolisthesis of the axis. There were nine males and six females with a mean age of 37 years at surgery. The cause of injury was a road traffic accident in 11 patients and a fall from height in 4 patients. All patients had a single stage reduction and direct transpedicular screw fixation through the C2 pedicles. During follow-up, clinical evaluation and plain X-rays were performed at each visit; at 6-month follow-up, additional dynamic lateral flexion/extension views and a CT scan were performed. The average follow-up period was 32 months (range 25–56 months). At final follow-up, all patients were asymptomatic and regained a good functional outcome with no limitation of range of motion; all the patients showed solid union with no implant failure. There were no neurological complications. At 6-month follow-up, CT evaluation showed fusion in all patients and an adequate position of 28 screws. Two pedicle screws (6.6%) showed minimal (defined as <2 mm) intrusion; one into the spinal canal and the other into the vertebral foreamen. Transpedicular screw fixation through the C2 pedicles is a safe and effective method in treating type II traumatic spondylolisthesis of the axis resulting in good clinical and radiological outcomes. Adequate reduction was achieved and motion segments were preserved with its use.
Hangman’s fracture; Transpedicular screw; Motion preservation; Cervical spine
The technique of posterior lumbar interbody fusion allows decompression of the spinal canal and interbody fusion through one posterior incision. A number of techniques exist to achieve additional posterior stability. The literature reports wide variation in outcomes for these different techniques. We assessed retrospectively the clinical and radiological outcome of posterior lumbar interbody fusion (PLIF) supplemented with an instrumented postero-lateral fusion (IPLF) using a pedicle screw system. Between July 1987 and April 1997, 60 patients underwent PLIF + IPLF. Clinical outcome was measured with physical examination in the outpatient setting and a patient questionnaire (patient satisfaction, analgesic use, return to work, Oswestry Disability Index). Radiological outcome was assessed with serial radiographs. If doubt existed regarding fixation, flexion/extension radiographs and plain tomograms were performed. The mean age was 44 years (range 19–69 years). The average follow-up was 5.3 years (range 1–10 years). Eighty percent of patients returned sufficiently completed questionnaires; 83% of these patients rated their outcome as good or excellent. Fifty percent of patients were able to return to full-time employment. All patients showed radiographic evidence of stable fixation. Four patients sustained a neurological complication, three of which resolved completely. The combination of PLIF with IPLF demonstrates clinical success, a stable circumferential fixation and a low complication rate.
Key words Posterior lumbar ¶interbody fusion; Instrumented ¶postero-lateral fusion; Surgical ¶technique; Clinical outcome; Radiological outcome
Posterior lumbar interbody fusion (PLIF) using threaded cages has gained wide popularity for lumbosacral spinal disease. Our biomechanical tests showed that PLIF using a single diagonal cage with unilateral facetectomy does add a little to spinal stability and provides equal or even higher postoperative stability than PLIF using two posterior cages with bilateral facetectomy. Studies also demonstrated that cages placed using a posterior approach did not cause the same increase in spinal stiffness seen with pedicle screw instrumentation, and we concluded that cages should not be used posteriorly without other forms of fixation. On the other hand, placement of two cages using a posterior approach does have the disadvantage of risk to the bilateral nerve roots. We therefore performed a prospective study to determine whether PLIF can be accomplished by utilizing a single diagonal fusion cage with the application of supplemental transpedicular screw/rod instrumentation. Twenty-seven patients underwent a PLIF using one single fusion cage (BAK, Sulzer Spine-Tech, Minneapolis, MN, USA) inserted posterolaterally and oriented anteromedially on the symptomatic side with unilateral facetectomy and at the same level supplemental fixation with a transpedicular screw/rod system. The internal fixation systems included 12 SOCON spinal systems (Aesculap AG, Germany) and 15 TSRH spinal systems (Medtronic Sofamor Danek, USA). The inclusion criteria were grade 1 to 2 lumbar isthmic spondylolisthesis, lumbar degenerative spondylolisthesis, and recurrent lumbar disc herniations with instability. Patients had at least 1 year of low back pain and/or unilateral sciatica and a severely restricted functional ability in individuals aged 28–55 years. Patients with more than grade 2 spondylolisthesis or adjacent-level degeneration were excluded from the study. Patients were clinically assessed prior to surgery by an independent assessor; they were then reassessed at 1, 3, 6, 12, 18, and 24 months postoperatively by the same assessor and put into four categories: excellent, good, fair, and poor. Operative time, blood loss, hospital expense, and complications were also recorded. All patients achieved successful radiographic fusion at 2 years, and this was achieved at 1 year in 25 out of 27 patients. At 2 years, clinical results were excellent in 15patients, good in 10, fair in 1, and poor in 1. Regarding complications, one patient had a postoperative motor and sensory deficit of the nerve root. Reoperation was required in one patient due to migration of pedicle screws. No implant fractures or deformities occurred in any of the patients. PLIF using diagonal insertion of a single threaded cage with supplemental transpedicular screw/rod instrumentation enables sufficient decompression and solid interbody fusion to be achieved with minimal invasion of the posterior spinal elements. It is a clinically safer, easier, and more economical means of accomplishing PLIF.
Lumbar Fusion cage Implant Transpedicular screw Interbody
Grade 5 spondylolisthesis or spondyloptosis is a rare condition. Generally, the surgical management of spondyloptosis includes multi-staged procedures instead of one-staged procedures. One-stage treatment for spondyloptosis is very rare. A 15-year-old girl with L5-S1 spondyloptosis was admitted with severe low back pain. There was no history of trauma. The patient underwent L5 laminectomy, L5-S1 discectomy, resection of sacral dome, reduction, L3-L4-L5-S1 pedicular screw fixation, and interbody-posterolateral fusion through the posterior approach. The reduction was maintained with bilateral L5-S1 discectomy, resection of the sacral dome, and transpedicular instrumentation from L3 to S1. In this particular case, one-staged approach was adequate for the treatment of L5-S1 spondyloptosis. One-staged surgery using the posterior approach may be adequate for the treatment of L5-S1 spondyloptosis while avoiding the risks inherent in anterior approaches.
Internal reduction; pedicular fixation; spondylolisthesis; spondyloptosis
Iliac screw fixation has been used to prevent premature loosening of sacral fixation and to provide more rigid fixation of the sacropelvic unit. We describe our technique for iliac screw placement and review our experience with this technique.
Thirteen consecutive patients who underwent spinopelvic fixation using iliac screws were enrolled. The indications for spinopelvic fixation included long segment fusions for spinal deformity and post-operative flat-back syndrome, symptomatic pseudoarthrosis of previous lumbosacral fusions, high-grade lumbosacral spondylolisthesis, lumbosacral tumors, and sacral fractures. Radiographic outcomes were assessed using plain radiographs, and computed tomographic scans. Clinical outcomes were assessed using the Oswestry Disability Index (ODI) and questionnaire about buttock pain.
The median follow-up period was 33 months (range, 13-54 months). Radiographic fusion across the lumbosacral junction was obtained in all 13 patients. The average pre- and post-operative ODI scores were 40.0 and 17.5, respectively. The questionnaire for buttock pain revealed the following: 9 patients (69%) perceived improvement; 3 patients (23%) reported no change; and 1 patient (7.6%) had aggravation of pain. Two patients complained of prominence of the iliac hardware. The complications included one violation of the greater sciatic notch and one deep wound infection.
Iliac screw fixation is a safe and valuable technique that provides added structural support to S1 screws in long-segment spinal fusions. Iliac screw fixation is an extensive surgical procedure with potential complications, but high success rates can be achieved when it is performed systematically and in appropriately selected patients.
Spinopelvic fixation; Iliac screws; Lumbosacral fusion; Outcome; Complication
We retrospectively evaluated 488 percutaneous pedicle screws in 110 consecutive patients that had undergone minimally invasive transforaminal lumbar interbody fusion (MITLIF) to determine the incidence of pedicle screw misplacement and its relevant risk factors. Screw placements were classified based on postoperative computed tomographic findings as “correct”, “cortical encroachment” or as “frank penetration”. Age, gender, body mass index, bone mineral density, diagnosis, operation time, estimated blood loss (EBL), level of fusion, surgeon’s position, spinal alignment, quality/quantity of multifidus muscle, and depth to screw entry point were considered to be demographic and anatomical variables capable of affecting pedicle screw placement. Pedicle dimensions, facet joint arthritis, screw location (ipsilateral or contralateral), screw length, screw diameter, and screw trajectory angle were regarded as screw-related variables. Logistic regression analysis was conducted to examine relations between these variables and the correctness of screw placement. The incidence of cortical encroachment was 12.5% (61 screws), and frank penetration was found for 54 (11.1%) screws. Two patients (0.4%) with medial penetration underwent revision for unbearable radicular pain and foot drop, respectively. The odds ratios of significant risk factors for pedicle screw misplacement were 3.373 (95% CI 1.095–10.391) for obesity, 1.141 (95% CI 1.024–1.271) for pedicle convergent angle, 1.013 (95% CI 1.006–1.065) for EBL >400 cc, and 1.003 (95% CI 1.000–1.006) for cross-sectional area of multifidus muscle. Although percutaneous insertion of pedicle screws was performed safely during MITLIF, several risk factors should be considered to improve placement accuracy.
Risk factor; Percutaneous; Pedicle screw; Minimally invasive; TLIF
Although percutaneous posterior-ring tension-band metallic plate and percutaneous iliosacral screws are used to fix unstable posterior pelvic ring fractures, the biomechanical stability and compatibility of both internal fixation techniques for the treatment of Denis I, II and III type vertical sacral fractures remain unclear.
Using CT and MR images of the second generation of Chinese Digitized Human “male No. 23”, two groups of finite element models were developed for Denis I, II and III type vertical sacral fractures with ipsilateral superior and inferior pubic ramus fractures treated with either a percutaneous metallic plate or a percutaneous screw. Accordingly, two groups of clinical cases that were fixed using the above-mentioned two internal fixation techniques were retrospectively evaluated to compare postoperative effect and function. Parallel analysis was performed with a finite element model controlled trial and a case control study.
The difference of the postoperative Majeed standards and outcome rates between two case groups was no statistically significant (P > 0.05). Accordingly, the high values of the maximum displacements/stresses of the plate-fixation model group approximated those of the screw-fixation model group. However, further simulation of Denis I, II and III type fractures in each group of models found that the biomechanics of the plate-fixation models became increasingly stable and compatible, whereas the biomechanics of the screw-fixation models maintained tiny fluctuations. When treating Denis III fractures, the biomechanical effects of the pelvic ring of the plate-fixation model were better than the screw-fixation model.
Percutaneous plate and screw fixations are both appropriate for the treatment of Denis I and II type vertical sacral fractures; whereas percutaneous plate fixation appears be superior to percutaneous screw fixation for Denis III type vertical sacral fracture. Biomechanical evidence of finite element evaluations combined with clinical evidence will contribute to our ability to distinguish between indications that require plate or screw fixation for vertical sacral fractures.
Vertical sacral fractures; Percutaneous internal fixation; Biomechanical stability; Biomechanical compatibility; Finite element model controlled trial; Clinical case study
Nerve root decompression with instrumented spondylodesis is the most frequently performed surgical procedure in the treatment of patients with symptomatic low-grade spondylolytic spondylolisthesis. Nerve root decompression without instrumented fusion, i.e. Gill's procedure, is an alternative and less invasive approach. A comparative cost-effectiveness study has not been performed yet. We present the design of a randomised controlled trial on cost-effectiveness of decompression according to Gill versus instrumented spondylodesis.
All patients (age between 18 and 70 years) with sciatica or neurogenic claudication lasting more than 3 months due to spondylolytic spondylolisthesis grade I or II, are eligible for inclusion. Patients will be randomly allocated to nerve root decompression according to Gill, either unilateral or bilateral, or pedicle screw fixation with interbody fusion. The main primary outcome measure is the functional assessment of the patient measured with the Roland Disability Questionnaire for Sciatica at 12 weeks and 2 years. Other primary outcome measures are perceived recovery and intensity of leg pain and low back pain. The secondary outcome measures include, incidence of re-operations, complications, serum creatine phosphokinase, quality of life, medical consumption, costs, absenteeism, work perception, depression and anxiety, and treatment preference. The study is a randomised prospective multicenter trial in which two surgical techniques are compared in a parallel group design. Patients and research nurse will not be blinded during the follow-up period of 2 years.
Currently, nerve root decompression with instrumented fusion is the golden standard in the surgical treatment of low-grade spondylolytic spondylolisthesis, although scientific proof justifying instrumented spondylodesis over simple decompression is lacking. This trial is designed to elucidate the controversy in best surgical treatment of symptomatic patients with low-grade spondylolytic spondylolisthesis.
In posterior lumbar interbody
vertebral fusion operations, variously sized, rectangular
shaped, defatted, freeze-dried, gas-sterilised cortical bone
allografts were used in combination with cancellous bone
autografts from excised posterior elements. Single-level fusion,
with or without internal fixation, was undertaken in 38 patients
aged 50 years or less with disc herniation or a failed
discectomy (the younger group) and in 33 women aged 60 years or
more with degenerative spondylolisthesis (the older group). Of
the various observable indicators of union, changes in the
allograft-host interface alone proved to be of practical use.
The incidence of nonunion in patients managed with pedicle
screws, with a hook and rod system or without internal fixation
was 0 of 8 patients; 1 of 14 patients; and 3 of 16 patients,
respectively, in the younger group, and 0 of 11 patients; 0 of 8
patients; and 2 of 14 patients, respectively, in the older
group. Of the six patients with nonunion, three had persistent
low back pain and only two had mobility of the fused segment
which was evident on lateral radiographs during flexion and
extension. No patient had graft collapse. The decrease in the
height of the intervertebral space, chiefly due to settlement of
the allograft into the vertebral bodies, in the younger and
older groups averaged 1.1 and 1.6 mm, respectively. We concluded
that this simplified technique is mechanically sound and
effective in maintaining the height of the intervertebral space.
Even when the graft failed to unite, fibrous union could be
obtained without graft collapse. Combination with a simple
internal fixator, such as a compression rod, facilitates bone