Surgical treatment of symptomatic degenerative lumbar spondylolisthesis by decompression and instrumented fusion

Degenerative spondylolisthesis is characterized by the slippage of one vertebral body over the one below, with association of intervertebral disc degeneration and degenerative arthritis of the facet joints, which cause spinal stenosis. The aim of this study was to evaluate the clinical and radiographic results of 22 patients with symptomatic degenerative spondylolisthesis, operated on by decompressive laminectomy and instrumented posterolateral fusion associated with interbody fusion (PLIF). Mean age at surgery was 64 years (range, 57–72). Clinical results were evaluated on a questionnaire at the last follow-up visit concerning postoperative low back and leg pain, restriction of daily life activities, and resumption of sports activity. Lumbar spine radiographs were used to evaluate the status of fixation devices, the reduction of the spondylolisthesis, the lumbar sagittal balance and the presence of spinal fusion. No intraoperative or postoperative complications were encountered. There were no superficial or deep infections, fixation device loosening, or hardware removal. Mean follow-up time was 4 years (range, 3–6 years). Clinical outcome was excellent or good in 19 patients and fair in 3 patients. Preoperatively, mean forward vertebral slipping on neutral lateral radiographs was 5 mm, while postoperatively it decreased to 3 mm. Preoperatively, mean sagittal motion was 3 mm and angular motion was 8°, while postoperatively these values decreased to 1 mm and 1°, respectively. This study demonstrated that spinal decompression followed by transpedicular instrumentation associated with PLIF technique is a valid surgical option for the treatment of degenerative spondylolisthesis with symptomatic spinal stenosis. Clinical outcome, intended as relief of pain and resumption of activity, was improved significantly and fusion rate was high.     

In-hospital postoperative radiographs for instrumented single-level degenerative spinal fusions: utility after intraoperative fluoroscopy

Background contextThere is a paucity of literature examining the clinical yield of in-hospital postoperative radiographs for patients who have had instrumented single-level spinal fusions with intraoperative fluoroscopic guidance. Many spinal surgeons consider postoperative standing radiographs to be the appropriate standard of care, even in patients who have an uneventful postoperative course.PurposeTo evaluate the additional clinical yield and cost-effectiveness of in-hospital postoperative standing radiographs for patients undergoing instrumented single-level cervical and lumbar fusions in which intraoperative fluoroscopy is used. Are postoperative standing radiographs necessary before hospital discharge?Study designRetrospective review of 100 consecutive degenerative spinal surgical cases in which intraoperative fluoroscopic imaging was compared with immediate postoperative radiographs using a vertebral grid mapping technique.MethodsA retrospective review of 100 consecutive patients who had an instrumented single-level cervical (30) or lumbar (70) fusion for a degenerative spinal condition performed by the same surgeon using intraoperative fluoroscopy. All patients had a documented uneventful postoperative hospitalization without evidence of new postoperative neurologic finding. All patients had both anteroposterior (AP) and lateral intraoperative fluoroscopic images and same-hospitalization standing AP and lateral radiographic images, which were performed within 72 hours postoperatively. Intraoperative and postoperative images were compared by two observers independently using a vertebral grid mapping technique to locate screw position and control magnification differences. Study parameters included screw tip position grids, interbody graft position, segmental sagittal plane alignment, spondylolisthesis grade, and hospital charges for patient imaging and interpretation.ResultsEarly instrumentation failure and/or screw position change was not observed in any patient. Seventy-four patients demonstrated a grid match for all screw tip positions on both true AP and lateral radiographs. Twenty-six patients had either a postoperative AP or lateral radiograph that was clinically malrotated and precluded comparison with the intraoperative true fluoroscopic images. Segmental sagittal alignment difference between intraoperative fluoroscopic and postoperative radiographic sagittal images averaged only 1.2° (range, 0–9) and was not statistically significant (paired Student t test, p=.88). Significant difference between intraoperative and immediate postoperative interbody graft position and spondylolisthesis grade was not demonstrated in any patient. Patient hospital billing charges for postoperative AP and lateral radiographic imaging with interpretation averaged $600.ConclusionsIn patients who have a single-level instrumented fusion and a documented uneventful postoperative course, in-hospital postoperative standing AP and lateral radiographs do not appear to provide additional clinically relevant information when intraoperative fluoroscopy is properly used. Fluoroscopy also demonstrated more consistent accuracy and a potential for significant cost savings.     

L4-5 degenerative spondylolisthesis. The results of treatment by decompressive laminectomy without fusion

The results of the treatment of L4-5 degenerative spondylolisthesis by decompressive laminectomy and partial facetectomy without fusion are presented. Patients who met the following criteria were studied: 1) A slip of at least 10%; 2) No compensation/litigation issues involved; 3) No prior surgery; and 4) Follow-up of at least 18 months. Twenty-four patients with an average follow-up of 34 months (range, 18 to 71 months) are reported. The average preoperative slip measured 7 mm (17%; range, 4-12 mm). Sixteen patients, including all patients less than 60 years of age, underwent preoperative supine lateral flexion-extension radiographs for evaluation of instability. No patient had greater than 2 mm of increase in slip on flexion-extension testing. During decompression, the structural integrity of the pars interarticularis and facet joints are preserved. There were 20 good, three fair, and one poor results. The average postoperative slip measured 8 mm (20%; range, 4-11 mm), and no patient had an increase in slip of greater than 4 mm. In the absence of objective instability on preoperative flexion-extension lateral radiographs in L4-5 degenerative spondylolisthesis, decompressive laminectomy with preservation of the structural integrity of the pars interarticularis and articular processes does not require routine spinal fusion and produced satisfactory clinical results.     

The safety and efficacy of OP-1 (rhBMP-7) as a replacement for iliac crest autograft for posterolateral lumbar arthrodesis: minimum 4-year follow-up of a pilot study.

BACKGROUND CONTEXT: Although autogenous bone is still considered to be the gold standard graft material for promoting spinal fusion, other bone graft substitutes have been developed in an attempt to improve arthrodesis rates and avoid the complications associated with the procurement of autograft. The bone morphogenetic proteins (BMPs) represent a family of osteoinductive growth factors that are known to stimulate the osteoblastic differentiation of stem cells. Osteogenic protein-1 (OP-1) Putty is a commercially available BMP preparation that is already approved for use in humans. Previous clinical studies involving patients with degenerative spondylolisthesis have reported that the efficacy and safety of OP-1 Putty is comparable to that of autograft at both 1- and 2-year follow-up. PURPOSE: The purpose of this study was to evaluate the intermediate-term efficacy and safety of OP-1 Putty as an alternative to autogenous bone by comparing the 4-year radiographic, clinical, and safety data of these same patients who underwent decompression and uninstrumented fusion with either OP-1 Putty or iliac crest autograft. STUDY DESIGN/SETTING: A prospective, randomized, controlled, multicenter clinical pilot study. PATIENT SAMPLE: Thirty-six patients undergoing decompressive laminectomy and single-level uninstrumented fusion for degenerative spondylolisthesis and symptomatic spinal stenosis were randomized in a 2:1 fashion to receive either OP-1 Putty (24 patients) or autogenous iliac crest bone graft (12 patients). OUTCOME MEASURES: Patient-reported outcome measures consisting of Oswestry Disability Index and Medical Outcomes Study 36-Item Short Form Health Survey (SF-36) scores were used to evaluate clinical efficacy. Perioperative data including operative time, estimated blood loss, and duration of hospital stay were also recorded for each surgery. Postoperatively, a neurological examination and an assessment of donor-site pain (if applicable) were performed at every follow-up visit. Radiographic fusion success was defined as the presence of continuous bridging bone formation between the transverse processes at the level of the spondylolisthesis with minimal motion evident on dynamic lateral x-ray films. The primary efficacy endpoint was the overall success rate, a composite measure derived from both radiographic and clinical parameters. The safety of OP-1 Putty was confirmed by comparing the nature and frequency of all adverse events and complications that were prospectively observed in either of the groups. METHODS: Thirty-six patients with degenerative spondylolisthesis and symptoms of neurogenic claudication underwent decompressive laminectomy and single-level uninstrumented fusion with either OP-1 Putty or autograft. All patients were evaluated at 6 weeks and 3, 6, 9, 12, and 24 months, after which time they were instructed to return on a yearly basis. Multiple neuroradiologists blinded to the assigned treatment reviewed static and dynamic X-ray films with digital calipers to assess fusion status according to the presence of continuous bridging bone across the transverse processes as well as the amount of residual motion evident at the level of interest. Oswestry Disability Index surveys and SF-36 questionnaires were used to assess clinical outcomes. RESULTS: At the 48-month time point, complete radiographic and clinical data were available for 22 of 36 patients (16 OP-1 Putty and 6 autograft) and 25 of 36 patients (18 OP-1 Putty and 7 autograft), respectively. Radiographic evidence of a solid arthrodesis was present in 11 of 16 OP-1 Putty patients (68.8%) and 3 of 6 autograft patients (50%). Clinically successful outcomes defined as at least a 20% improvement in preoperative Oswestry scores were experienced by 14 of 19 OP-1 Putty patients (73.7%) and 4 of 7 autograft patients (57.1%); these clinical findings were corroborated by similar increases in SF-36 scores. The respective overall success rates of the OP-1 Putty and autograft group were 62.5% and 33.3%. In this study, there were no incidents of local or systemic toxicity, ectopic bone production, or other adverse events directly related to the use of OP-1 Putty. CONCLUSION: Despite the challenges associated with obtaining a solid uninstrumented fusion in patients with degenerative spondylolisthesis, the rates of radiographic fusion, clinical improvement, and overall success associated with the use of OP-1 Putty were at least comparable to that of the autograft controls for at least 48 months after surgery. These results appear to validate the short-term results previously reported for OP-1 Putty and suggest that this material may potentially represent a viable bone graft substitute for certain fusion applications.     

Imaging characteristics of “dynamic” versus “static” spondylolisthesis: analysis using magnetic resonance imaging and flexion/extension films

Background contextTraditionally, the “dynamic” and “static” types of spondylolisthesis have been lumped into a single group in the literature. The goal of this study was to define the radiographic characteristics of “dynamic” and “static” spondylolisthesis with the use of magnetic resonance imaging (MRI) and flexion/extension radiographs.PurposeDescribe the characteristic findings present on MRI and flexion/extension radiographs that are associated with dynamic versus static spondylolisthesis.Study designRetrospective radiographic/imaging study.MethodsFrom 2009 to 2011, patients who underwent elective primary posterior spinal fusion for the diagnosis of spondylolisthesis had their plain films assessed for the degree of spondylolisthesis and were designated “dynamic” or “static,” as defined by historical measures. Axial and sagittal T2 MRIs were evaluated for associated facet fluid (FF), facet cysts, interspinous fluid (ISF), and facet hypertrophy. These finding were then statistically evaluated for associations between dynamic and static spondylolisthesis on flexion/extension radiographs and characteristic MRI findings.ResultsNinety patients were included in the study with 114 levels examined for spondylolisthesis. Patients with greater than 3 mm of instability on flexion/extension films were more likely to have FF (p=.018) and ISF (p<.001). Of the patients who had a greater than 3 mm of instability, 39.5% did not demonstrate spondylolisthesis on the sagittal MRI reconstruction. If ISF was present on MRI, there was a positive predictive value of 69.0% that there would be greater than 3 mm instability on flexion/extension films. Absence of FF on MRI had a positive predictive value of 75.6% for instability less than 3 mm on flexion/extension films. In the presence of ISF on MRI, the likelihood ratio of finding more than 3 mm of instability on flexion/extension films was 3.68. The presence of FF on MRI had a likelihood ratio of 1.43 for instability. A total of 36.8% of all spondylolisthesis reduced when supine on MRI.ConclusionsThe presence of FF and/or ISF is associated with instability greater than 3 mm in flexion/extension radiographs.     

Increased risk of symptomatic progression of instability following decompression for lumbar canal stenosis in patients receiving chronic glucocorticoids therapy

Background

Lumbar decompression surgery is a commonly used treatment for degenerative lumbar spinal stenosis; however, some patients develop symptomatic spinal instability following decompression surgery. The objective of this study was to reveal risk factors for delayed instability following decompression surgery for lumbar spinal stenosis.

A pilot safety and efficacy study of OP-1 putty (rhBMP-7) as an adjunct to iliac crest autograft in posterolateral lumbar fusions

The ability of bone morphogenetic proteins (BMPs) to induce bone formation has led to an increasing interest in the potential for their use in fusion surgery. The purpose of this multi-center clinical pilot study was to evaluate the safety of one such BMP—osteogenic protein 1, in the form of OP-1 putty—combined with autograft for intertransverse process fusion of the lumbar spine in patients with symptomatic spinal stenosis and degenerative spondylolisthesis following spinal decompression. Twelve patients with spinal stenosis and degenerative lumbar spondylolisthesis underwent laminectomy and partial or complete medial facetectomy as required for decompression of the neural elements followed by intertransverse process fusion by placing iliac crest autograft and OP-1 putty between the decorticated transverse processes. No instrumentation was used. Patients were followed clinically using the Oswestry scale and radiographically using static and dynamic radiographs to assess their fusion status. Independent and blinded radiologists assessed the films for the presence of bridging bone between the transverse processes and measured translation and angulation on dynamic films using digital calipers. In addition to bridging bone, less than or equal to 5° of angular motion and less than or equal to 2 mm of translation were required to classify the patients as successfully fused, as per the definition of successful fusion provided by the FDA for use in clinical trials involving investigational devices to attain spinal fusion. Radiographic outcome was compared to a historical control (autograft alone fusion without instrumentation for the treatment of degenerative spondylolisthesis). All adverse events were recorded prospectively. The results showed 9 of the 12 patients (75%) obtained at least a 20% improvement in their preoperative Oswestry score, while 6 of 11 patients (55%) with radiographic follow-up achieved a solid fusion by the criteria used in this study. Bridging bone on the anteroposterior film was observed in 10 of the 11 patients (91%). No systemic toxicity, ectopic bone formation, recurrent stenosis or other adverse events related to the OP-1 putty implant were observed. A successful fusion was observed in slightly over half the patients in this study, using stringent criteria without adjunctive spinal instrumentation. This study did not demonstrate the superiority of OP-1 combined with autograft over an autograft alone historical control, in which the fusion rate was approximately 45%. The lack of adverse events related to the OP-1 putty implant in this study is in agreement with other studies supporting the safety of bone morphogenetic proteins in spinal surgery.     

Facet fusion in the lumbosacral spine: a 2-year follow-up study

OBJECTIVE: A clinical and radiological follow-up study was undertaken to assess the safety, efficacy, and complication rate associated with instrumented facet fusion of the lumbar and lumbosacral spine. METHODS: This study involved 99 patients with degenerative lumbar disorders who were treated surgically at the authors' neurosurgical department and followed for more than 2 years. Eighty-two patients underwent one-level fusion for the treatment of Grade I or II degenerative spondylolisthesis and accompanying spinal canal stenosis (44 patients) or recurrent disc herniation (38 patients). Seventeen patients underwent two-level fusion for the treatment of either double instances of the above indications (seven patients) or concurrent stenosis at the adjacent level (10 patients). RESULTS: There were no technique-related complications. The overall 2-year success rate of fusion was 96%; the success rates by fusion type were 99% in one-level fusions and 88% in two-level fusions. Degenerative spondylolisthesis had the highest success rate at 100%, whereas the success rate in patients who had not responded to previous discectomy was 93%. Patients with concurrent stenosis experienced the lowest success rate: 80%. Excellent or good clinical results were obtained for 85% of patients with one-level fusions and for 65% of patients with two-level fusions. CONCLUSION: Instrumented facet fusion alone is a simple, safe, and effective surgical option for the treatment of patients with single-level disorders, especially patients with degenerative spondylolisthesis.     

Does fusion status following posterolateral lumbar fusion in the treatment for stable lumbar degenerative spondylolisthesis affect the long-term surgical outcomes? A propensity score-weighted analysis of consecutive patients

BackgroundThe surgical strategy of lumbar degenerative spondylolisthesis (LDS) is controversial, especially regarding whether or not fusion should be used. Although some reports have indicated that decompression combined with fusion may be better than decompression alone in the treatment of LDS, the effect of fusion status after uninstrumented posterolateral lumbar fusion (PLF) on the outcomes of patients with stable LDS remains unknown. This study aimed to evaluate the surgical outcomes of uninstrumented PLF for stable LDS and clarify whether radiographic fusion status could affect surgical outcomes.MethodsA total of 93 consecutive patients who had undergone single-level uninstrumented PLF for Meyerding grade I LDS without preoperative dynamic instability with a minimum follow-up period of 5 years were retrospectively studied. Patients were divided into two groups: nonunion (52 patients) and union (41 patients). The primary outcomes were the 5-year percent recovery of postoperative Japanese Orthopaedic Association (JOA) scores, Oswestry Disability Index (ODI), Visual analog scale (VAS) scores, and reoperation rate. The outcome scores were compared between the groups using the inverse probability weighting method using propensity scores.ResultsThe union and nonunion groups had comparable weighted means of the 5-year postoperative clinical score for the percent recovery of the JOA score (70.2% vs. 71.1%, P = 0.86), ODI (14.5 vs.14.6, P = 0.98), VAS of low back pain (20.3 vs. 18.7 mm, P = 0.72), and VAS of leg pain (24.0 vs. 19.4 mm, P = 0.43). The reoperation rate was 2.4% (one case of adjacent segment pathology) in the union group and 0% in the nonunion group (P = 0.44).ConclusionThe fusion status following uninstrumented PLF had no significant effect on the 5-year postoperative clinical outcomes and reoperation rate in patients with Meyerding grade I LDS without dynamic instability.     

Cervical kinematics after fusion and bryan disc arthroplasty

INTRODUCTION: Disc arthroplasty has been shown to provide short-term clinical results that are comparable with those attained with traditional anterior cervical discectomy and fusion. One proposed benefit of arthroplasty is the ability to prevent or delay adjacent level operations by retaining motion at the target level and eliminating abnormal adjacent activity. This paper compares motion parameters for single-level anterior cervical discectomy and fusion and disc replacement patients at the index level and adjacent segments. METHODS: Radiographic data from patients enrolled in a prospective, randomized clinical trial were selected for kinematic assessment of cervical motion. All patients received either a single-level fusion with allograft and anterior cervical plate (Atlantis anterior cervical plate, n=13) or a single-level artificial cervical disc (Bryan Cervical Disc prosthesis, n=9) at either C5/C6 or C6/C7. Flexion, extension, and neutral lateral radiographs were obtained preoperatively, immediately postoperatively, and at regular intervals up to 24-month time points. Cervical vertebral bodies were tracked on the digital radiographs using quantitative motion analysis software (QMA, Medical Metrics) to calculate the functional spinal unit motion parameters including range of motion (ROM), translation, and center of rotation. If visible, the functional spinal unit parameters were obtained at the operative level, and also the level above and the level below. RESULTS: As expected, significantly (P<0.006 at 3, 6, 12, and 24 mo) more flexion/extension motion was retained in the disc replacement group than the plated group at the index level. The disc replacement group retained an average of 6.7 degrees at 24 months. In contrast, the average ROM in the fusion group was 2.0 degrees at the 3-month follow-up and gradually decreased to 0.6 degrees at 24 months. The flexion/extension ROM both above and below the operative level was not statistically different for the disc-replaced and fusion patients, however, mobility increased for both groups over time. The anterior/posterior translation that occurs with flexion/extension motion remained unchanged for the disc replacement group at the level above the target disc preoperatively and postoperatively. In contrast, the translation increased for the level above the fusion. At the 6-month follow-up, the increase in translation was significantly greater for patients that were fused (P<0.02) than for patients that received a disc replacement. This change was not significant at 12 months. DISCUSSION: Previous studies have shown the Bryan disc to maintain mobility at the level of the prosthesis. The long-term clinical benefit of maintenance of motion is postulated to be the ability to delay or avoid adjacent level operations. This study reveals that there is no difference in flexion/extension ROM at the level above and below either a fusion or Bryan arthroplasty. There is, however, an increase in anterior/posterior translation at the cephalad adjacent level in patients with arthrodesis while the Bryan arthroplasty retains normal translation for the same amount of flexion/extension at the adjacent level. CONCLUSION: The Bryan disc may delay adjacent level degeneration by preserving preoperative kinematics at adjacent levels.     

Microsurgical treatment of juxta facet cysts of the lumbar spine

OBJECTIVES: Juxta facet cysts are a common cause of low back and radicular pain. They are mostly associated with degenerative facet joints and spondylolisthesis. The study focuses on long-term outcomes after microsurgical treatment without fusion. METHOD: From April 2002 to April 2004, 31 patients (23 female and 8 male) underwent microsurgical resection of lumbar juxta facet cysts. The patient age ranged from 31 to 83 years (mean 67.2 years). The most affected level was L4-L5 (19 patients), followed by L3-L4 (9 patients). Fourteen patients additionally had spondylolisthesis of the involved segment. All patients had signs of nerve root compression and had received conservative treatment preoperatively. We performed limited bone removal (sparing the facet joints) and cyst resection in 27 patients. In four patients, cyst resection and standard laminectomy were performed owing to spinal stenosis. RESULTS: Conservative treatment was without any effect in all patients. At follow-up, 12-30 months after surgery, excellent to good outcome was achieved in 25 of 31 patients (80.7%), and 6 patients (19.3%) showed fair results. Persistent low back pain was more common in patients with spondylolisthesis than in the other group (6/14 vs 3/17); this may be due to instability. Spondylolisthesis did not progress or become mobile after surgery radiographically in any of our patients. CONCLUSIONS: Conservative therapy does not adequately improve symptoms in patients with intraspinal juxta facet cysts and radicular signs. Juxta facet cysts can be treated effectively with a minimally invasive microsurgical approach. This may be of particular significance when the cysts are associated with spondylolisthesis, minimizing the risk of instability and the need for fusion. In a selected group of patients with persistent low back pain, fusion may become necessary to improve symptoms.     

Bone regrowth after surgical decompression for lumbar spinal stenosis.

We reviewed 40 patients treated surgically for lumbar stenosis at an average time of 8.6 years after operation. In 32, total laminectomy had been performed and in eight bilateral laminotomy, both at one or more levels. Of the 16 patients with degenerative spondylolisthesis, ten had had a concomitant spinal fusion. Patients were assigned to one of four groups according to the amount of bone regrowth: group 0 had no regrowth and groups I, II, and III, had mild, moderate or marked regrowth, respectively. Only 12% of the patients showed no bone regrowth; 48% were assigned to group I, 28% to group II and 12% to group III. Imaging studies showed varying degrees of recurrent stenosis in patients with moderate or marked bone regrowth. All patients with degenerative spondylolisthesis showed bone regrowth, which was more severe in those who had not had a fusion. The clinical results were satisfactory in most of the patients with mild or no bone regrowth and significantly less good in those with moderate or marked regrowth. In the group with degenerative spondylolisthesis, the proportion of satisfactory results was significantly higher in patients who had had spinal fusion. The long-term results of surgery for lumbar stenosis depend both upon the amount of bone regrowth and the degree of postoperative vertebral stability.     

Spinal stenosis in grade I degenerative lumbar spondylolisthesis: a comparative study of outcomes following laminoplasty and laminectomy with instrumented spinal fusion

The management of grade I lumbar degenerative spondylolisthesis remains controversial. There have been few reports comparing any form of surgery with conservative treatment. As for surgical management, the need for arthrodesis with instrumentation has not been established. A series of 53 patients with single-level spinal stenosis at L4/5 due to grade I degenerative spondylolisthesis entered into a study to compare outcomes of two surgical methods of treatment with those of a control group treated conservatively: group 1, 19 patients treated by decompression laminectomy combined with posterolateral fusion and pedicle screw instrumentation; group 2, 18 patients treated by decompression of the spinal canal using a laminoplasty technique to preserve the integrity of the midline structure; group 3, 16 patients treated conservatively after being recommended that they have surgery. We compared the 2-year results among the three groups. Alleviation of symptoms was noted in groups 1 and 2, whereas the controls (group 3) showed no improvement. There was no significant difference in the degree of clinical improvement between groups 1 and 2. Spondylolisthesis was controlled in group 1, but it did not lead to better clinical results than those achieved in group 2. Our findings indicate that the technique for decompressing the spinal canal with preservation of the posterior elements of its roof can be useful for treating patients with grade I degenerative spondylolisthesis with symptoms of spinal stenosis.     

Low risk for vertebral slipping after decompression with facet joint preserving technique for lumbar spinal stenosis

Summary The incidence and magnitude of vertebral slipping after decompression for central lumbar spinal stenosis were determined in a prospective study of 60 consecutive patients. Mean patient age was 64 (35–83) years, and 35 patients were men. In all cases, laminectomy was performed using a facet joint preserving undercutting technique. Plain radiographs were obtained before and 1 year after surgery. Vertebral slipping and disc degeneration were measured. Preoperative degenerative olisthesis was seen in 19 of the 60 patients. Further slipping had occurred in 6 of these patients by 1 year post-operatively. Of the remaining 41 patients, only 1 showed a postoperative slipping. Improvement concerning leg pain was reported by 45 patients, and there was no difference in patients with or without postoperative slipping. It is concluded that decompression with a facet joint preserving technique yielded a low risk for post-operative vertebral slipping. The risk for slip was higher in patients with preoperative degenerative olisthesis but was still less than 1/3. Vertebral slipping did not influence the outcome of the operation at 1 year. Our results do not support the routine use of spinal fusion in connection with decompression for lumbar spinal stenosis.     

Uninstrumented in situ fusion for high-grade childhood and adolescent isthmic spondylolisthesis: long-term outcome

BACKGROUND: Intermediate-term radiographic studies have shown that anterior and circumferential techniques result in high fusion rates in patients with high-grade spondylolisthesis, whereas posterolateral fusion is less successful. We are not aware of any long-term comparative studies in which these three methods have been evaluated with regard to functional outcome, including systematic spinal mobility and trunk strength measurements. METHODS: Sixty-nine of eighty-three consecutive patients with high-grade isthmic spondylolisthesis who underwent posterolateral (twenty-one), anterior (twenty-three), or circumferential (twenty-five) uninstrumented spondylodesis between 1977 and 1991 participated in the study. The average duration of follow-up was 17.2 years. Radiographs that were made preoperatively and at the time of the most recent follow-up were assessed with regard to fusion quality and degenerative changes. Outcome was assessed at the time of the most recent follow-up by independent observers on the basis of a physical examination, spinal mobility and nondynamometric trunk strength measurements, and Oswestry Disability Index scores. RESULTS: The mean preoperative vertebral slip was 61% in the posterolateral fusion group, 63% in the anterior fusion group, and 71% in the circumferential fusion group. The final fusion rate was 86% (eighteen of twenty-one) in the posterolateral fusion group, 100% (twenty-three of twenty-three) in the anterior fusion group, and 96% (twenty-four of twenty-five) in the circumferential fusion group. A decrease in lumbar intervertebral disc height at the first mobile level superior to the fusion was noted in five patients in the posterolateral fusion group, seven patients in the anterior fusion group, and one patient in the circumferential fusion group (p = 0.037). The mean Oswestry Disability Index score was 9.7 for the posterolateral fusion group, 8.9 for the anterior fusion group, and 3.0 for the circumferential fusion group (p = 0.035). Nondynamometric trunk strength measurements corresponded with referential values. Abnormally low lumbar flexion affected the posterolateral and circumferential fusion groups more often than the anterior fusion group (p = 0.0015). The percentage of slip showed inverse correlations with lumbar flexion, lumbar extension, and trunk side-bending. CONCLUSIONS: As assessed on the basis of patient-based outcomes, circumferential in situ fusion provided slightly better long-term results than did posterolateral or anterior in situ fusion. When the radiographic and functional results were combined with the patient-based outcomes, the overall differences between the three groups were small.     

腰椎退行性多节段滑脱的手术治疗

目的 探讨腰椎退行性多节段滑脱的手术治疗方法.方法 2005年3月至2008年9 月,采用后路彻底减压、复位、椎弓根内螺钉固定360°融合治疗多节段腰椎滑脱患者25例.其中男性7例,女性18例;年龄38-75岁,平均56.6岁.滑脱均为退行性变化引起,类型有:前滑脱12例,后滑脱2例,混合滑脱11例.患者均行腰椎后路减压融合手术,术后随访6个月-4年,根据 Lenke 标准评价脊柱植骨融合情况,根据 Henderson 标准评价临床疗效.结果 术后25例患者均获得完全 复位.植骨融合结果:Lenke A级23例,B级2例;临床疗效Henderson评价结果:优16例,良6例,可 3例.结论 多节段腰椎退变滑脱发病机制和治疗方法与单节段腰椎滑脱不尽相同,后路彻底减压, 适度复位,后外侧植骨融合结合椎间融合能获得较好的临床效果.多节段滑脱复位时应根据滑脱的类型选择不同方法.     

A 2-year follow-up pilot study evaluating the safety and efficacy of op-1 putty (rhbmp-7) as an adjunct to iliac crest autograft in posterolateral lumbar fusions

The ability of bone morphogenetic proteins (BMPs) to induce bone formation has led to a multitude of investigations into their use as bone graft substitutes in spinal surgery. The purpose of this multi-center clinical pilot study was to evaluate the safety and efficacy of BMP-7 (osteogenic protein 1, OP-1), in the form of a putty, combined with autograft for intertransverse process fusion of the lumbar spine in patients with symptomatic spinal stenosis and degenerative spondylolisthesis following spinal decompression. Twelve patients with spinal stenosis and degenerative lumbar spondylolisthesis underwent a laminectomy and partial or complete medial facetectomy as required for decompression of the neural elements, followed by an intertransverse process fusion by placing iliac crest autograft and OP-1 putty between the decorticated transverse processes. No instrumentation was used. Patients were followed clinically using the Oswestry scale and SF-36 outcome forms, and radiographically using static and dynamic radiographs to assess their fusion status over a 2-year period. Independent and blinded radiologists assessed the films for the presence of bridging bone between the transverse processes and measured translation and angulation on dynamic films using digital calipers. Radiographic outcome was compared to a historical control (autograft alone fusion without instrumentation for the treatment of degenerative spondylolisthesis). All adverse events were recorded prospectively. The results showed eight of the nine evaluable patients (89%) obtained at least a 20% improvement in their preoperative Oswestry score, while five of ten patients (50%) with radiographic follow-up achieved a solid fusion by the criteria used in this study. Bridging bone on the anteroposterior film was observed in seven of the ten patients (70%). No systemic toxicity, ectopic bone formation, recurrent stenosis or other adverse events related to the OP-1 putty implant were observed. A successful fusion was observed in slightly over half the patients in this study, using stringent criteria without adjunctive spinal instrumentation. This study did not demonstrate the statistical superiority of OP-1 combined with autograft over an autograft alone historical control, in which the fusion rate was 45%. There were no adverse events related to the OP-1 putty implant in this study, which supports findings in other studies suggesting the safety of bone morphogenetic proteins in spinal surgery.     

Instrumented Facet Fusion for the Degenerative Lumbar Disorders

Summary  A new, simple, minimally morbid procedure used to treat degenerative lumbar spinal disorders is described. The authors based their treatment on the McBride technique of facet fusion, which was modified and supplemented with pedicle screw fixation.  The first 32 consecutive patients with degenerative spondylolisthesis and failed back surgery syndrome were treated, and followed for more than a year. Surgically, 26 patients had a single level fusion, and 6 patients had a two level fusion. Postoperative radiographs and computed tomography (CT) scans were evaluated to determine the fusion status.  There were no specific complications related with the facet fusion. Thirty of 32 (93.8%) had solid fusions according to the computed tomographic criteria. Two patients showed a questionable union on CT scan but motion was less than 5 degrees on dynamic films. While 96.2% (25/26) of patients with a single level procedure had solid fusion, rate of union in the patients with two level procedures was 83.3% (5/6).  This preliminary study of 32 patients shows that instrumented facet fusion appears to be a safe and effective procedure for lumbar spine fusions, demonstrating a high fusion rate with rarely serious complications.     

Radiographic analysis of transforaminal lumbar interbody fusion for the treatment of adult isthmic spondylolisthesis

The radiographs of 35 consecutive adult patients with isthmic spondylolisthesis who underwent a transforaminal lumbar interbody fusion (TLIF) with one or two Brantigan carbon fiber cages and pedicle screw instrumentation were evaluated. Anterolisthesis, disk space height, and slip angle were measured in preoperative and postoperative standing neutral radiographs. Anterolisthesis was reduced and disk space height was increased with the TLIF procedure. Average slip angle, however, was not significantly altered. The restoration of lordosis across the listhetic disk space correlated with a more anterior placement of the interbody cage within the disk space. The TLIF technique, performed with the Brantigan cage and pedicle screw instrumentation, appears to be able to restore disk height and reduce forward translation in patients with isthmic spondylolisthesis, but improvement in sagittal alignment is dependent upon anterior placement of the interbody device.     

椎弓根螺钉固定小关节融合术治疗Ⅰ度腰椎滑脱临床效果评价

目的评价椎弓根螺钉固定小关节融合术治疗Ⅰ度腰椎滑脱的临床效果。方法回顾性分析2005年10月至2008年7月收治的35例单节段Ⅰ度腰椎滑脱行小关节融合患者的临床资料。其中男性8例,女性27例;年龄27～88岁,平均年龄61.1岁。术前和末次随访时采用VAS、ODI评分进行临床评价,融合情况采用X线片及CT平扫并矢状位重建进行评价。结果 35例患者均获随访,随访时间14～48个月,平均25.4个月。术后滑脱复位率为75.8%,术前、术后及末次随访的滑脱率比较差异均有统计学意义（P=0.000）;末次随访VAS和ODI评分与术前比较差异均有统计学意义（P=0.000）。末次随访患者主观优良率为94.3%。X线片和CT评价融合率分别为94.3%和97.1%。并发症有出现退变性侧凸2例（分别在术后15和17个月随访时发现）,术后14个月出现上方邻近节段后滑脱1例,术后早期出现伤口延迟愈合行清创术1例。结论椎弓根螺钉固定小关节融合术治疗Ⅰ度腰椎滑脱是一种简单易行的手术方式,其融合率及手术效果满意。