Surgical versus nonsurgical therapy for lumbar spinal stenosis

Abstract

Background: Surgery for spinal stenosis is widely performed, but its effectiveness as compared with nonsurgical treatment has not been shown in controlled trials.

Methods: Surgical candidates with a history of at least 12 weeks of symptoms and spinal stenosis without spondylolisthesis (as confirmed on imaging) were enrolled in either a randomized cohort or an observational cohort at 13 U.S. spine clinics. Treatment was decompressive surgery or usual nonsurgical care. The primary outcomes were measures of bodily pain and physical function on the Medical Outcomes Study 36-item Short-Form General Health Survey (SF-36) and the modified Oswestry Disability Index at 6 weeks, 3 months, 6 months, and 1 and 2 years.

Results: A total of 289 patients were enrolled in the randomized cohort, and 365 patients were enrolled in the observational cohort. At 2 years, 67% of patients who were randomly assigned to surgery had undergone surgery, whereas 43% of those who were randomly assigned to receive nonsurgical care had also undergone surgery. Despite the high level of nonadherence, the intention-to-treat analysis of the randomized cohort showed a significant treatment effect favoring surgery on the SF-36 scale for bodily pain, with a mean difference in change from baseline of 7.8 (95% confidence interval, 1.5 to 14.1); however, there was no significant difference in scores on physical function or on the Oswestry Disability Index. The as-treated analysis, which combined both cohorts and was adjusted for potential confounders, showed a significant advantage for surgery by 3 months for all primary outcomes; these changes remained significant at 2 years.

Conclusions: In the combined as-treated analysis, patients who underwent surgery showed significantly more improvement in all primary outcomes than did patients who were treated nonsurgically. (ClinicalTrials.gov number, NCT00000411 [ClinicalTrials.gov].).

Copyright 2008 Massachusetts Medical Society.

Figures

Figure 1 (facing page). Enrollment, Randomization, and Follow-up

The numbers of patients who withdrew from the study, died, or underwent surgery are cumulative during the 2-year follow-up period.

Figure 2. Primary Outcomes in the Randomized and Observational Cohorts during 2 Years of Follow-up

The graphs show both the intention-to-treat and the as-treated analyses for the randomized cohort (column on left) and the as-treated analysis for the observational cohort (column on right). Results for bodily pain and physical function are scores on the Medical Outcomes Study 36-item Short-Form General Health Survey (SF-36), ranging from 0 to 100, with higher score indicating less severe symptoms. The Oswestry Disability Index (bottom row) ranges from 0 to 100, with lower scores indicating less severe symptoms. The horizontal dashed line in each of the four SF-36 graphs represents normal values adjusted for age and sex. The I bars represent 95% confidence intervals. At 0 months, the floating data points represent the observed mean scores for each study group, whereas the data points on plot lines represent the overall means used in the adjusted analyses.