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spondylolisthesis, rehabilitation, surgery, treatment. BACKGROUND. It is not known whether surgery is more effective than nonsurgical treatment for the.
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Is surgery more effective than nonsurgical treatment for the management of patients with degenerative spondylolisthesis? Original article Weinstein JN et al. (2007) Surgical versus nonsurgical treatment for lumbar degenerative spondylolisthesis. N Engl J Med 356: 2257–2270

KEYWORDS lumbar degenerative spondylolisthesis, rehabilitation, surgery, treatment

function measurements using the Medical Outcomes Study 36-Item Short-form General Health Survey (SF-36) and overall score on the modified Oswestry Disability Index (both 100point scales). Secondary outcome measures included patient-reported improvement and satisfaction with current symptoms and care.

BACKGROUND

RESULTS

It is not known whether surgery is more effective than nonsurgical treatment for the management of patients with degenerative spondylolisthesis with spinal stenosis.

A total of 304 patients were included in the randomized cohort, and 303 were included in the observational group; all patients had similar baseline demographic characteristics. Surgery was assigned to 159 patients in the randomized group, and to 173 patients in the observational group. In the randomized group of patients, crossover rates were 40% in each treatment direction after 1 year, compared with more moderate figures in the observational group (17% crossover to surgery and 3% crossover to nonsurgical treatment). No statistically significant differences were shown on intention-to-treat analyses between the two treatments in the randomized group. As-treated analysis of the randomized and observational groups showed significant improvements after 3 months in patients who underwent surgery, increasing after 1 year and lasting until 2 years. At 2 years, the effect of surgery was 18.1 (95% CI 14.6–21.7) for pain and 18.3 (95% CI 14.6–21.9) for physical function on the SF-36 questionnaire, and –16.7 on the Oswestry Disability Index (95% CI –19.5 to –13.9).

SYNOPSIS

OBJECTIVE

The objective of this study was to compare the effects of surgical versus nonsurgical intervention on pain and physical function in patients with degenerative spondylolisthesis. DESIGN AND INTERVENTION

The Spine Patient Outcomes Research Trial (SPORT) included two separate patient cohort studies: a randomized trial and an observational study. Patients included in both studies had symptoms of degenerative spondylolisthesis confirmed by radiography for a duration longer than 12 weeks. Patients with spondylosis and isthmic spondylolisthesis were excluded from the study. Patients in the randomized trial were randomly allocated to receive either surgical treatment with decompressive laminectomy or standard nonsurgical treatment. Patients in the observational study received the treatment of their choice. All patients were assessed after 6 weeks of treatment, and again at months 3, 6, 12 and 24. Both intention-to-treat and as-treated analyses were performed. OUTCOME MEASURES

The primary outcome measure of this study was improvement in pain and physical

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CONCLUSION

The authors conclude that patients who undergo surgical treatment of degenerative spondylolisthesis and spinal stenosis experience increased improvements in pain and function after 2 years compared with patients who receive nonsurgical treatment.

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C O M M E N TA RY JN Alastair Gibson* and Chye-Yew Ng The need for improved clinical evidence that supports surgical practice in the treatment of degenerative disc disease was highlighted in a recent Cochrane Review of randomized controlled trials.1 Weinstein and colleagues now report results from the second cohort of patients in the $21 million national Spine Patients Outcomes Research Trial (SPORT), funded by the National Institutes of Health. Data from the first part of the trial, which compared surgical and nonsurgical treatments for lumbar disc herniation, was published in 2006;2 the data regarding spinal stenosis as a single disease entity is awaited. The SPORT disc trial received much attention from both the scientific and general press. A recent editorial in The Spine Journal discussed concerns about the validity of the trial results,3 most of them relating to the interpretation of the spondylolisthesis data. By the end of the 2-year study, the crossover rates in the randomized group were approximately 40% in each direction. This means that the intention-to-treat analysis, which showed no statistically significant differences between the groups in any primary outcome measure, is liable to underestimate the treatment effect of surgery. By contrast, the as-treated analysis of the combined data from the randomized and observational cohorts has a diminished internal validity. The treatment choice is not precisely controlled for known and unknown factors that might be associated with each outcome, even though the two groups are similar at baseline. This would lead to an overestimate of the treatment effect of surgery. The true results probably lie somewhere between those stated for the two different analyses. If the results from the SPORT study are accepted, then care should be taken with their translation to common surgical practice. In the nonoperative group the protocol was ‘usual’ care, recommended to include at least active physical therapy and education. The issue with this is similar to that levied against the Swedish lumbar fusion trial,4 as many patients will have considered their treatment to have ‘already failed’, leading to potentially negative expectations. In the surgical group, the intervention was

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not standardized; a posterior decompressive laminectomy was performed, with or without bilateral single-level fusion, which could be with iliac bone alone or supplemented by posterior pedicle-screw instrumentation. We do know from a recent meta-analysis that spinal fusion and decompression produces better clinical outcomes than simple decompression.5 This heterogeneity of treatment limits the conclusions that can be drawn; however, accepting this fact, it is interesting to note that the combined surgical group gained relief from their symptoms rapidly, with improvements observed as early as 6 weeks postoperatively. These benefits were maintained for 2 years, which is generally accepted as a ‘worthwhile’ period. In many Western countries the population is increasingly ageing, and, consequently, the incidence of spinal stenosis is rising. Overall, the underlying message from this article is that surgery will produce greater improvements in pain and function than nonsurgical treatment when stenosis occurs in the presence of a degenerative spondylolisthesis; however, much better comparative data supporting specific surgical and nonsurgical interventions are still required. The cost-effectiveness analysis, which is expected to be published towards the end of 2007, should indicate whether the benefits achieved by surgery warrant the use of limited state health resources. References 1 Gibson JN and Waddell G (2005) Surgery for degenerative lumbar spondylosis: updated Cochrane Review. Spine 30: 2312–2320 2 Weinstein JN et al. (2006) Surgical vs nonoperative treatment for lumbar disk herniation: the Spine Patient Outcomes Research Trial (SPORT): a randomized trial. JAMA 296: 2441–2450 3 Angevine PD and McCormick PC (2007) Inference and validity in the SPORT herniated disc randomized clinical trial. The Spine J 7: 387–391 4 Fritzell P et al. (2001) 2001 Volvo Award Winner in Clinical Studies: Lumbar fusion versus nonsurgical treatment for chronic low back pain: a multicenter randomized controlled trial from the Swedish Lumbar Spine Study Group. Spine 26: 2521–2534 5 Martin CR et al. (2007) The surgical management of degenerative lumbar spondylolisthesis: a systematic review. Spine 32: 1791–1798

JNA Gibson is a Consultant Spinal Surgeon and C-Y Ng is a Spinal Registrar, both at the Royal Infirmary of Edinburgh. JNA Gibson is also a Senior Lecturer at the University of Edinburgh, Scotland.

Acknowledgments The synopsis was written by Jasmine Farsarakis, Associate Editor, Nature Clinical Practice.

Competing interests The authors declared no competing interests.

Correspondence *University Department of Orthopaedic Surgery The Royal Infirmary of Edinburgh Little France Edinburgh EH16 4SU UK j.n.a.gibson@ blueyonder.co.uk Received 11 September 2007 Accepted 19 November 2007 Published online 18 December 2007 www.nature.com/clinicalpractice doi:10.1038/ncprheum0705

PRACTICE POINT A surgical option should be explored for patients with lumbar degenerative spondylolisthesis and accompanying spinal stenosis

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