Degenerative Lumbar Spondylolisthesis Surgery
When considering surgical treatment variations with data from the Spine Patient Outcomes Research Trial (SPORT), 7% were treated with decompression alone, 21% were treated with non-instrumented fusion, and 71% were treated with fusion surgery 1).
A meta-analysis in 2014 found that inclusion of fusion surgery with instrumentation provided no benefit as evaluated by patient-reported outcomes in patients with lumbar spondylolisthesis 2).
The role of arthrodesis in the surgical management of lumbar spondylolisthesis remains controversial. Azad et al., hypothesized that practice patterns and outcomes for this patient population may vary widely.
They calculated arthrodesis rates, inpatient and long term costs, and key quality indicators (e.g. reoperation rates). Using linear and logistic regression models, they then calculated expected quality indicator values, adjusting for patient-level demographic factors, and compared these values to the observed values, to assess quality variation apart from differences in patient populations.
They identified a cohort of 67,077 patients (60.7% female, mean age of 59.8 years (SD, 12.0) with lumbar spondylolisthesis who received either laminectomy or laminectomy with arthrodesis. The majority of patients received arthrodesis (91.8%). Actual rates of arthrodesis varied from 97.5% in South Dakota to 81.5% in Oregon. Geography remained a significant predictor of arthrodesis even after adjusting for demographic factors (p<0.001). Marked geographic variation was also observed in initial costs ($32,485 in Alabama to $78,433 in Colorado), two-year post-operative costs ($15,612 in Arkansas to $34,096 in New Jersey), length of hospital stay (2.6 days in Arkansas to 4.5 in Washington, D.C.), 30-day complication rates (9.5% in South Dakota to 22.4% in Maryland), 30-day readmission rates (2.5% in South Dakota to 13.6% in Connecticut), and reoperation rates (1.8% in Maine to 12.7% in Alabama).
There is marked geographic variation in the rates of arthrodesis in treatment of spondylolisthesis within the United States. This variation remains pronounced after accounting for patient-level demographic differences. Costs of surgery and quality outcomes also vary widely. Further study is necessary to understand the drivers of this variation 3).
Lumbar interbody fusion for degenerative lumbar spondylolisthesis treatment showed better results in terms of fusion rate and sacral slope, but which did not translate into better clinical outcomes. Further randomized and prospective studies are necessary to elucidate the optimal therapeutic options 4).
Surgery is widely used and has recently been shown to be more effective than nonoperative treatment when the results were followed over two years. Questions remain regarding the long-term effects of surgical treatment compared with those of nonoperative treatment.
The standard surgical treatment for degenerative spondylolisthesis with lumbar stenosis is lumbar fusion following standard laminectomy. Although this strategy is widely adopted, it is not supported by class I evidence. This strategy assumes that degenerative spondylolisthesis worsens the outcome of laminectomy by causing postoperative instability. However, instability may be reduced or prevented by the use of less invasive decompression techniques.
In a trial involving patients who underwent surgery for degenerative lumbar spondylolisthesis, most of whom had symptoms for more than a year, decompression alone was noninferior to decompression with instrumented fusion over a period of 2 years. Reoperation occurred somewhat more often in the decompression-alone group than in the fusion group. (NORDSTEN-DS ClinicalTrials.gov number, NCT02051374.) 5)
Spoor et al. present a novel noninstrumented surgical approach for patients with isthmic spondylolisthesis, with clinical and radiographic results.
Charts of patients who underwent this technique were reviewed. The procedure consisted of nerve root decompression by reconstruction of the intervertebral foramen. This was achieved by removal of the pedicle followed by noninstrumented posterolateral fusion in which autologous bone graft from the right iliac crest was used. Outcomes regarding radicular complaints, bony fusion, progression of the slip, and complications were evaluated using patient history and radiographs obtained at follow-up intervals of 3-18 months after surgery. RESULTS A total of 58 patients with a mean age of 47 years were treated with this method. Partial removal of the pedicle was performed in 93.1% of the cases, whereas in 6.9% of the cases the entire pedicle was removed. The mean duration of surgery was 216.5 ± 54.5 minutes (range 91-340 minutes). The mean (± SD) duration of hospitalization was 10.1 ± 2.9 days (range 5-18 days). After 3 months of follow-up, 86% of the patients reported no leg pain, and this dropped to 81% at last follow-up. Radiographic follow-up showed bony fusion in 87.7% of the patients. At 1 year, 5 patients showed progression of the slip, which in 1 patient prompted a second operation within 1 year. No major complications occurred. CONCLUSIONS Treatment of isthmic spondylolisthesis by reconstruction of the intervertebral neuroforamen and posterolateral fusion in situ is a safe procedure and has comparable results with the existing techniques. Cost-effectiveness research comparing this technique to conventional instrumented fusion techniques is necessary to evaluate the merits for both patients and society 6).
Lumbar laminectomy plus lumbar spinal fusion: may be indicated for patients with degenerative lumbar spondylolisthesis, lumbar spinal stenosis and radiculopathy, adult degenerative scoliosis (ADS), or instability.
Surgery for lumbar spondylolisthesis is indicated if symptoms are disabling and interfere with work, if the condition is progressive, or if there is a significant neurological deficit. The ideal surgical treatment remains controversial 7).
Lumbar fusion for spondylolisthesis tends to yield more consistent outcomes than fusion for degenerative disc disease and discogenic low back pain.
NASS Guidelines
The North American Spine Society's (NASS) Evidence-Based Clinical Guideline for the Diagnosis and Treatment of Degenerative Lumbar Spondylolisthesis features evidence-based recommendations for diagnosing and treating degenerative lumbar spondylolisthesis. The guideline updates the 2008 guideline on this topic and is intended to reflect contemporary treatment concepts for symptomatic degenerative lumbar spondylolisthesis as reflected in the highest quality clinical literature available on this subject as of May 2013. The NASS guideline on this topic is the only guideline on degenerative lumbar spondylolisthesis included in the Agency for Healthcare Research and Quality's National Guideline Clearinghouse (NGC).
Purpose: The purpose of this guideline is to provide an evidence-based educational tool to assist spine specialists when making clinical decisions for patients with degenerative lumbar spondylolisthesis. This article provides a brief summary of the evidence-based guideline recommendations for diagnosing and treating patients with this condition.
Study design: A systematic review of clinical studies relevant to degenerative spondylolisthesis was carried out.
Methods: This NASS spondyolisthesis guideline is the product of the Degenerative Lumbar Spondylolisthesis Work Group of NASS' Evidence-Based Guideline Development Committee. The methods used to develop this guideline are detailed in the complete guideline and technical report available on the NASS website. In brief, a multidisciplinary work group of spine care specialists convened to identify clinical questions to address in the guideline. The literature search strategy was developed in consultation with medical librarians. Upon completion of the systematic literature search, evidence relevant to the clinical questions posed in the guideline was reviewed. Work group members used the NASS evidentiary table templates to summarize study conclusions, identify study strengths and weaknesses, and assign levels of evidence. Work group members participated in webcasts and in-person recommendation meetings to update and formulate evidence-based recommendations and incorporate expert opinion when necessary. The draft guidelines were submitted to an internal peer review process and ultimately approved by the NASS Board of Directors. Upon publication, the Degenerative Lumbar Spondylolisthesis guideline was accepted into the NGC and will be updated approximately every 5 years.
Results: Twenty-seven clinical questions were addressed in this guideline update, including 15 clinical questions from the original guideline and 12 new clinical questions. The respective recommendations were graded by strength of the supporting literature, which was stratified by levels of evidence. Twenty-one new or updated recommendations or consensus statements were issued and 13 recommendations or consensus statements were maintained from the original guideline.
Conclusions: The clinical guideline was created using the techniques of evidence-based medicine and best available evidence to aid practitioners in the care of patients with degenerative lumbar spondylolisthesis. The entire guideline document, including the evidentiary tables, literature search parameters, literature attrition flow chart, suggestions for future research, and all of the references, is available electronically on the NASS website at https://www.spine.org/Pages/ResearchClinicalCare/QualityImprovement/ClinicalGuidelines.aspx and will remain updated on a timely schedule 8).
Techniques
Posterior lumbar interbody fusion
The optimal surgical management of lumbar spinal stenosis patients with spondylolisthesis remains controversial.
The best medical evidence available in the literature confirms the utility of fusion for improving patient outcomes following decompression for stenosis associated with spondylolisthesis. The majority of evidence from other studies comparing outcomes after decompression alone or decompression combined with PLF in patients with stenosis and spondylolisthesis also favors the performance of PLF. The medical evidence regarding the use of pedicle screw fixation in this patient population is rated as Class III and is inconsistent. A consistent benefit associated with the use of pedicle screw fixation has been reported in patients with preoperative instability or kyphosis. Iatrogenic instability following decompression is associated with poor outcomes and may also be treated with PLF involving supplemental instrumentation. The precise definition of instability or kyphosis has varied among researchers and requires further study 9).
In 165 consecutive patients who underwent unilateral laminotomy with bilateral decompression (ULBD), the patients were prospectively followed with a standardized questionnaire, short-form 36 (SF-36), and standing lumbar x-rays for a maximum follow-up period of 5 years. According to the presence or absence of degenerative spondylolisthesis, the patients were divided into two groups: an olisthesis group and a non-olisthesis group.
The average SF-36 physical score and bodily pain score improved substantially immediately after surgery. This improvement was maintained up to 5 years postoperatively. Progression of slippage was uncommon in both groups, with an overall incidence of 8% at 5 years follow-up. There was no significant difference in the average physical score, the bodily pain score, or the rate of progression of slippage between the olisthesis and non-olisthesis groups.
It indicates that preoperative degenerative spondylolisthesis does not worsen the outcome of patients with lumbar stenosis undergoing ULBD. These results suggest that lumbar fusion is often unnecessary in patients with degenerative spondylolisthesis and lumbar stenosis if the posterior decompression technique is ULBD 10).