Anterior spondylodesis for spondylolisthesis: isthmic and degenerative types

Is Stand-Alone Anterior Lumbar Interbody Fusion a Safe and Efficacious Treatment for Isthmic Spondylolisthesis of L5-S1?

STUDY DESIGN

A systematic review.

OBJECTIVE

The objective of this study was to determine the safety and efficacy of stand-alone anterior lumbar interbody fusion (sa-ALIF) for the treatment of symptomatic isthmic spondylolisthesis of L5-S1 by assessing the level of available clinical and radiographic evidence.

METHODS

A systematic review utilizing Medline, Embase, and Scopus online databases was undertaken. Clinical, radiographic, and adverse outcome data were extracted for the relevant isthmic spondylolisthesis cases with the intention of undertaking a meta-analysis.

RESULTS

The database search between January 1980 and December 2015 yielded 23 articles that concerned sa-ALIF for isthmic spondylolisthesis of L5-S1. Only in 9 of the 23 articles data could be extracted specific to sa-ALIF for isthmic spondylolisthesis of L5-S1. There was considerable inconsistency in the standards for reporting outcomes of the surgery due to which meta-analysis could not be undertaken, and hence each article was reviewed.

CONCLUSIONS

There was insufficient evidence to support the safety and efficacy of sa-ALIF for the treatment of isthmic spondylolisthesis of L5-S1. Although sa-ALIF is widely documented in the literature, there was insufficient evidence to support its use in treating this specific pathology. The unique pathological and anatomical situation that isthmic spondylolisthesis of L5-S1 presents must be recognized and its treatment with sa-ALIF should be well thought out.

Stand-alone anterior lumbar interbody fusion for treatment of degenerative spondylolisthesis

We sought to evaluate the clinical and radiologic efficacy of stand-alone anterior lumbar interbody fusion (ALIF) for low grade degenerative spondylolisthesis, the favoured surgical management approach at our institution. The optimal approach for surgical management of spondylolisthesis remains contentious. We performed a prospective analysis of all consecutive patients with low grade lumbar spondylolisthesis who underwent ALIF between 2009 and 2013 by a single surgeon (n=27). The mean age was 64.9 years with a male to female ratio of 14:13. There were 32 levels operated and the average preoperative spondylolisthesis was 14.8%, which reduced to 6.4% postoperatively and 9.4% at the latest follow-up (p=0001). Postoperative disc height was increased to 175% of preoperative values and was statistically significant (p<0.001) and remained improved with an overall change of 139% at the latest follow-up. The radiological fusion rate was 91%. The 12-Item Short Form Health Survey (SF-12) mental and physical component summary improved from 31.7 to 43.0 (p=0.007) and from 35.4 to 51.7 (p=0.0026), respectively. The mean visual analogue scale pain score improved from 7.6 to 2.2 (p<0.001), and the mean Oswestry disability index improved from 56.9 to 17.8% (p<0.0001). The overall clinical success rate was 93%. The posterior disc height correlated with spondylolisthesis reduction (p=0.04) and the only clinical factor affecting reduction was body mass index (p=0.04). The present study provides encouraging short term results for stand-alone ALIF as a procedure for low grade lumbar degenerative spondylolisthesis. Future studies should include adequately powered, prospective, multicentre registry studies with long term follow-up to allow a better assessment of the relative benefits and risks.

Comparison of functional outcomes following surgical decompression and posterolateral instrumented fusion in single level low grade lumbar degenerative versus isthmic spondylolisthesis

Background

The two most common types of surgically treated lumbar spondylolisthesis in adults include the degenerative and isthmic types. The aim of this study was to compare the functional outcomes of surgical decompression and posterolateral instrumented fusion in patients with lumbar degenerative and isthmic spondylolisthesis.

Methods

In this retrospective study, we reviewed the clinical outcomes in surgically treated patients with single level, low grade lumbar degenerative, and isthmic spondylolisthesis (groups A and B, respectively) from August 2007 to April 2011. We tried to compare paired settings with similar initial conditions. Group A included 52 patients with a mean age of 49.2 ± 6.1 years, and group B included 52 patients with a mean age of 47.3 ± 7.4 years. Minimum follow-up was 24 months. The surgical procedure comprised neural decompression and posterolateral instrumented fusion. Pain and disability were assessed by a visual analog scale (VAS) and the Oswestry Disability Index (ODI), respectively. The Wilcoxon and Mann-Whitney U-tests were used to compare indices.

Results

The most common sites for degenerative and isthmic spondylolisthesis were at the L4-L5 (88.5%) and L5-S1 (84.6%) levels, respectively. Surgery in both groups significantly improved VAS and ODI scores. The efficacy of surgery based on subjective satisfaction rate and pain and disability improvement was similar in the degenerative and isthmic groups. Notable complications were also comparable in both groups.

Conclusions

Neural decompression and posterolateral instrumented fusion significantly improved pain and disability in patients with degenerative and isthmic spondylolisthesis. The efficacy of surgery for overall subjective satisfaction rate and pain and disability improvement was similar in both groups.

Outcomes of anterior lumbar interbody fusion in low-grade isthmic spondylolisthesis in adults: a continuous series of 65 cases with an average follow-up of 6.6 years

INTRODUCTION

Surgical treatment of isthmic spondylolisthesis continues to be controversial. The fusion procedure can either be instrumented using a posterior and/or anterior approach or non-instrumented. The role of associated decompression, reduction of the slippage, disc height restoration and lordosis restoration has not definitely been established. The goal of this study was to evaluate the efficacy of anterior approach for interbody fusion (ALIF) without any reduction maneuver.

MATERIALS AND METHODS

Sixty-five patients with isthmic spondylolisthesis were operated on, using an ALIF. The average patient age was 40 years. The preoperative maximum walking time was 20 minutes. Ten patients had radiculopathy. The average preoperative Beaujon Hospital disability index was 9/20. Standard static and dynamic X-rays were evaluated in all patients; a CT scan was performed in 33 patients 1 year after the surgery. The olisthetic vertebra had slipped by an average of 12 mm. Thirty-five of the spondylolisthesis cases had abnormal vertebral motion.

RESULTS

At an average follow-up of 6.6 years, lumbar pain and radicular pain had been reduced by 4.6 and 5 points on the visual analogue scale, respectively. Twenty-seven patients could walk for an unlimited amount of time. Three patients still had radiculopathy. The Beaujon Hospital disability index had improved by an average of 7.3 points. The fusion rate was 91%. The slippage had decreased by 30%, despite no specific reduction maneuvers at the time of surgery. The disc height had increased by 177%. On the sagittal plane, lordosis had improved by 5°, without any changes in the pelvic parameters.

CONCLUSION

In situ ALIF provides results that are comparable to those obtained with other techniques. This study confirms the essential role of fusion in achieving good functional results, given that hypermobility of the olisthetic level contributes to the symptoms generation.

LEVEL OF EVIDENCE

Level IV. Retrospective study.

Role of lumbar interspinous distraction on the neural elements

The interspinous distraction devices are used to treat variable pathologies ranging from facet syndrome, diskogenic low back pain, degenerative spinal stenosis, diskopathy, spondylolisthesis, and instability. The insertion of a posterior element with an interspinous device (ISD) is commonly judged responsive to a relative kyphosis of a lumbar segment with a moderate but persistent increase of the spinal canal and of the foraminal width and area, and without influence on low-grade spondylolisthesis. The consequence is the need of shared specific biomechanical concepts to give for each degenerative problem the right indication through a critical analysis of all available experimental and clinical biomechanical data. We reviewed systematically the available clinical and experimental data about kyphosis, enlargement of the spinal canal, distraction of the interspinous distance, increase of the neural foramina, ligamentous structures, load of the posterior annulus, intradiskal pressure, strength of the spinous processes, degeneration of the adjacent segment, complications, and cost-effectiveness of the ISD. The existing literature does not provide actual scientific evidence over the superiority of the ISD strategy, but most of the experimental and clinical data show a challenging potential. These considerations are applicable with different types of ISD with only few differences between the different categories. Despite--or because of--the low invasiveness of the surgical implantation of the ISD, this technique promises to play a major role in the future degenerative lumbar microsurgery. The main indications for ISD remain lumbar spinal stenoses and painful facet arthroses. A clear documented contraindication is the presence of an anterolisthesis. Nevertheless, the existing literature does not provide evidence of superiority of outcome and cost-effectiveness of the ISD strategy over laminectomy or other surgical procedures. At this time, the devices should be used in clinical randomized independent trials in order to obtain more information concerning the most advantageous optimal indication or, in selected cases, to treat tailored indications.

Iatrogenic spinal deformity

Patients with postoperative spinal deformities are being identified with increasing frequency as the number of instrumented spinal operations increases. Thus, it is important for the neurosurgeon to understand ways to minimize postoperative deformity and to understand its operative and nonoperative management. A variety of intra- and postoperative risk factors have been associated with postoperative deformity, including patient age, operative positioning, preoperative medical condition, and the use of prior radiation therapy. The evaluation of all patients who have been suspected of iatrogenic deformity should include a detailed physical examination, plain x-rays, and computed tomographic or magnetic resonance imaging, depending on the condition. Conservative therapy includes physical therapy and pain control, which may be effective in some patients. However, patients with flat-back syndrome typically require reoperation. A wide variety of reoperative procedures may be performed, depending on the area of the pathological deformity, extent of disease, and patient condition.

The radiographic results and neurologic complications of instrumented reduction and fusion of high-grade spondylolisthesis without decompression of the neural elements: a retrospective review of 44 patients

STUDY DESIGN

A retrospective review of all cases of high-grade spondylolisthesis treated by 1 surgeon between the years 1991 and 2003.

OBJECTIVE

To report the radiographic results and neurologic complications following instrumented posterior reduction and fusion without decompression of the neural elements.

SUMMARY OF BACKGROUND DATA

Despite a large number of published reviews of the clinical results of operative intervention, controversy remains about the surgical treatment of high-grade spondylolisthesis.

METHODS

A retrospective review of the clinical charts and radiographs of all patients with L5-S1 spondylolisthesis and more than 50% anterior displacement of L5 on S1 who were treated by the same surgical team at 1 institution.

RESULTS

With this technique, an average reduction in the displacement of L5 on S1 from 64% to 38% was achieved. At a minimum 2-year follow-up (41 patients), we have detected 5 cases with evidence of pseudarthrosis or loss of reduction (11.4%). Overall, a neurologic complication rate of 9.1% occurred in this series, with a 2.3% chance of a persistent motor deficit. We did not detect any loss of bowel or bladder function after surgery. At last follow-up, and after revision procedures, we were able to achieve good or fair clinical results in 40 (90.9%) of 44 patients.

CONCLUSIONS

These data suggest that a posterior instrumented reduction and fusion of high-grade spondylolisthesis without decompression of the neural elements can be accomplished with acceptable radiographic and clinical results.

Fusion for low-grade adult isthmic spondylolisthesis: a systematic review of the literature

The objective of this study was to evaluate which fusion technique provides the best clinical and radiological outcome for adult low-grade lumbar isthmic spondylolisthesis, and to assess the overall clinical and radiological outcome of each fusion technique. A systematic review was performed. Medline, Embase, Current Contents, and Cochrane databases as well as reference lists of selected articles were searched. Randomised controlled trials (RCTs) were used to evaluate the best treatment; controlled studies and non-controlled studies were used to determine the outcomes after surgery. Two independent reviewers evaluated the studies with the methodological checklists of van Tulder and Jadad for the randomised studies and of Cowley for the non-randomised studies. The search resulted in 684 references and eventually 29 studies met the inclusion criteria, of which eight were RCTs, four were prospective, and 17 were retrospective case series. Ten of the case series did not clearly identify consecutive patient selection. All the eight RCTs evaluated the effect of different techniques of posterolateral fusion (PLF). Evidence was found that the PLF was superior to non-operative treatment (exercise). Circumferential fusion was compared to PLF, but no difference could be found. PLF with or without instrumentation was evaluated in three studies, but no benefits from additional instrumentation were found. Other comparisons within PLF showed no effect of decompression, alternative instrumentation, or bone graft substitute. The 21 case series included 24 patient groups. PLF was used in 15 groups, good or excellent clinical outcome varied from 60 to 98% and fusion rate varied from 81 to 100%. Anterior interbody fusion was used in five groups, good or excellent clinical outcome varied from 85 to 94% and fusion rate varied from 47 to 90%. Posterior interbody fusion was used in two groups, good or excellent clinical outcome was 45% and fusion rate was 80 and 95%, respectively. Reduction, loss of reduction, and lordotic angles before and after the treatment was reported in only four studies. Average reduction achieved was 12.3%, average loss of reduction at follow-up was 5.9%. Preoperative lordotic angles were too heterogeneous to pool the results. Adjacent segment degeneration was not reported in any of the publications. A wide variety of complications were reported in 18 studies and included neurological complications, instrument failure, and infections. Fusion for low-grade isthmic spondylolisthesis has better outcomes than non-operative treatment. The current study could not identify the best surgical technique (PLF, PLIF, ALIF, instrumentation) to perform the fusion. However, instrumentation and/or decompression may play a beneficial role in the modern practice of reduction and fusion for low-grade isthmic spondylolisthesis, but there are no studies yet available to confirm this. The outcomes of fusion are generally good, but reports vary widely.

A critical analysis of the literature regarding surgical approach and outcome for adult low-grade isthmic spondylolisthesis

OBJECTIVE

A systematic review of the radiographic and clinical outcomes of adult patients undergoing surgery for low-grade isthmic spondylolisthesis was performed to determine whether conclusions could be made regarding the optimal choice of surgically managing adult low-grade isthmic spondylolisthesis.

METHODS

We tabulated the radiographic and clinical outcomes of patients who underwent a posterior procedure alone, an anterior procedure alone, or a combined anterior and posterior procedure. We also evaluated the influence of covariates such as laminectomy, spinal internal fixation, smoking, and secondary gain issues on these outcomes. Patients were pooled, and a chi analysis was performed to determine the relationship between surgical approach and patient outcome. A covariate analysis was performed to determine the influence of a laminectomy, spinal fixation, smoking, and secondary gain issues on these outcomes.

RESULTS

The available literature consisted primarily of retrospective case series, with only 4 of 34 reports being prospective randomized controlled studies. Patients with combined anterior and posterior procedures were most likely to achieve a solid fusion and a successful clinical outcome. The use of spinal fixation also increased the chance of fusion and successful clinical outcome.

CONCLUSIONS

A pooling of the surgical literature on adult low-grade spondylolisthesis indicates that a combined anterior and posterior procedure most reliably achieves fusion and a successful clinical outcome. The literature, however, is primarily retrospective and heterogeneous with respect to indications for surgery and methods of evaluating outcome, providing a compelling rationale for a prospective randomized controlled trial of the various surgical approaches to this problem.

Adult low-grade acquired spondylolytic spondylolisthesis: evaluation and management

STUDY DESIGN

Literature review.

OBJECTIVE

To discuss the presentation and evaluation of adult patients with acquired spondylolytic spondylolisthesis of low-grade severity and to review surgical treatment options.

SUMMARY OF BACKGROUND DATA

Low-grade adult acquired spondylolytic spondylolisthesis is one of the most common forms of spondylolisthesis.

METHODS

Literature review.

RESULTS

Adults with symptomatic low-grade spondylolytic spondylolisthesis are treated predominantly nonoperatively, with activity modification, physiotherapy, nonsteroidal anti-inflammatory agents, and local injections. Surgical treatment is reserved for individuals with intractable back pain and/or radicular symptoms. A number of surgical options exist, including direct pars repair, and fusion with or without decompression. Fusion can be achieved by providing anterior column support alone, posterior support alone, or a combined circumferential approach; the optimal method by which fusion should be achieved has not been established.

CONCLUSIONS

The management of low-grade acquired spondylolytic spondylolisthesis requires a thoughtful and individualized approach, recognizing the frequently benign natural history of the deformity and the potentially good clinical outcomes from surgery in those select patients with intolerable back and leg pain. While fusion is the mainstay of surgical management, a prospective randomized study would be extremely useful to delineate the optimal fusion technique.

Comparison of the mechanical behavior of the lumbar spine following mono- and bisegmental stabilization

OBJECTIVE

To determine whether the mechanical behavior of the entire lumbar spine differs following mono- and bisegmental stabilization.

DESIGN

The mechanical behavior of the lumbar spine was studied using the finite element method.

BACKGROUND

Nonunion is somewhat more frequent after bi- than after monosegmental stabilization of the spine. Little is known about differences between the mechanical behavior associated with these procedures.

METHODS

A three-dimensional nonlinear finite element model of the lumbar spine with internal spinal fixators and bone grafts was used to study mechanical behavior after mono- and bisegmental fixation with and without stabilization of the bridged vertebra. Finite element analyses were performed to determine the influence of four different graft positions, five loading conditions, and six different pretensions in the longitudinal fixator rod. The following parameters were considered: the maximum contact pressure at the interface between the bone graft and vertebral body, the force transmitted by the bone graft, and the size of the contact area between the graft and the vertebral body.

RESULTS

Our model shows no clear differences between mono- and bisegmental fixation. Additional stabilization of the bridged vertebra exerts a partly adverse influence on the parameters studied. Pretension in the bridged region has a strong effect on the mechanical behavior.

CONCLUSIONS

The mechanical behavior of the lumbar spine after mono- and bisegmental stabilization is similar. Thus biological factors and the surgical procedure are probably decisive in determining the fusion rate.

RELEVANCE

Knowledge of the mechanical behavior after stabilization of the spine may help to improve the fusion rate. Our results suggest that the mechanical factors studied have only a minor influence on fusion rate and that other factors, such as incomplete resection of cartilage plate and poor local blood supply, are more decisive.

Standardized evaluation of long-term results after anterior lumbar interbody fusion

A total of 113 patients, excluding those with tumor, spondylitis, and idiopathic scoliosis, underwent anterior lumbar interbody fusion (ALIF) with autologous iliac crest graft between 1984 and 1991 at our department. The proportion of these who were failed back patients was higher than that reported in the literature. Evaluation of functional outcome was feasible in 80 patients, utilizing Oswestry and Marburg scores, which were closely intercorrelated. The overall results yielded an improvement in the Oswestry score of 35.7 percentage points. A subset of 52 patients who were evaluated twice, showed the same results at an average of 6.6 years as they did at 2.3 years following surgery. Functional results showed a weak correlation with postoperative height loss of the intervertebral space. Influencing factors for the functional result were: postoperative compensation claim, age, and obesity. Of the professional people involved, 19.4% did not return to any occupation. Patients satisfied with the result had significantly greater functional improvement. Younger patients with additional dorsal distraction prior to ALIF for reduction of severe spondylolisthesis fared better than patients with ALIF alone. The rate of complications was low and did not contribute to the postoperative functional result. On the basis of these results further prospective studies have been designed and are currently underway.