The Cochrane review of surgery for lumbar disc prolapse and degenerative lumbar spondylosis

STUDY DESIGN: A Cochrane review of randomized controlled trials.

OBJECTIVES: To collate the scientific evidence on surgical management for lumbar-disc prolapse and degenerative lumbar spondylosis.

SUMMARY OF BACKGROUND DATA: Surgical investigations and interventions account for as much as one third of the health care costs for spinal disorders, but the scientific evidence for most procedures still is unclear.

METHODS: A highly sensitive search strategy identified all published randomized controlled trials. Cochrane methodology was used for meta-analysis of the results.

RESULTS: Twenty-six randomized controlled trials of surgery for lumbar disc prolapse and 14 trials of surgery for degenerative lumbar spondylosis were identified. Methodologic weaknesses were found in many of the trials. Only one trial directly compared discectomy and conservative management. Meta-analyses showed that surgical discectomy produces better clinical outcomes than chemonucleolysis, which is better than placebo. Three trials showed no difference in clinical outcomes between microdiscectomy and standard discectomy, but in three other studies, both produced better results than percutaneous discectomy. Three trials showed that inserting an interposition membrane after discectomy does not significantly reduce scar formation or alter clinical outcomes. Five heterogeneous trials on spinal stenosis and degenerative spondylolisthesis permit very limited conclusions. There were nine trials of instrumented versus noninstrumented fusion: Meta-analysis showed that instrumentation may facilitate fusion but does not improve clinical outcomes.

CONCLUSIONS: There is now strong evidence on the relative effectiveness of surgical discectomy versus chemonucleolysis versus placebo. There is considerable evidence on the clinical effectiveness of discectomy for carefully selected patients with sciatica caused by lumbar disc prolapse that fails to resolve with conservative management. There is no scientific evidence on the effectiveness of any form of surgical decompression or fusion for degenerative lumbar spondylosis compared with natural history, placebo, or conservative management. The Cochrane reviews will be updated continuously as other trials become available.