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Two new randomized trials address surgery for herniated disk and spondylolisthesis.
Dutch researchers randomized 283 patients with 6 to 12 weeks of severe sciatica secondary to a herniated lumbar disk to either early microdiskectomy (within 2 weeks of randomization) or conservative treatment. Eighty-nine percent of those randomized to surgery actually underwent the procedure, and 39% of those randomized to conservative treatment crossed over to surgery during the first year. From about 4 weeks to 12 weeks, patients in the surgical group improved faster than those in the nonsurgical group on scores for disability, leg pain, and back pain. Thereafter, scores in the two groups converged, with differences disappearing at 1 year.
A U.S. study examined a different problem — lumbar degenerative spondylolisthesis with spinal stenosis, causing neurogenic claudication or radicular pain. About 300 patients (mean age, 66) were randomized to surgery (posterior decompressive laminectomy with fusion) or no surgery. At 1 year, about 40% of patients in each group had crossed over to the other treatment. In intention-to-treat analyses, the groups did not differ in disability, pain, and function at 2 years. The researchers also compared patients who actually underwent surgery and those who did not. For this as-treated analysis, the randomized cohort was combined with 303 observed patients who declined randomization. Surgical patients had significantly better 2-year outcomes than nonsurgical patients, after adjusting for baseline differences between groups.
Peul WC et al. Surgery versus prolonged conservative treatment for sciatica. N Engl J Med 2007 May 31; 356:2245-56.
Weinstein JN et al. Surgical versus nonsurgical treatment for lumbar degenerative spondylolisthesis. N Engl J Med 2007 May 31; 356:2257-70.
Comment
The herniated disk study supports the conventional wisdom regarding sciatica caused by a lumbar disk: Early surgery is associated with quicker recovery, but 1-year outcomes are similar to outcomes in patients who begin with conservative treatment and undergo surgery only if symptoms do not improve.
Interpretation of the study of symptomatic degenerative spondylolisthesis with spinal stenosis is more complex because of the high crossover rate in both groups. Surgery appears more favorable than a nonoperative approach, but this conclusion rests upon an as-treated analysis, which reintroduces some of the confounding that randomization avoids.