original articleT h e n e w e n gl a n d j o u r n a l o f m e d i c i nen engl j med 358;8 www.nejm.org february 21, 2008794Surgical versus Nonsurgical Therapy for Lumbar Spinal StenosisJames N. Weinstein, D.O., M.S., Tor D. Tosteson, Sc.D., Jon D. Lurie, M.D., M.S., Anna N.A. Tosteson, Sc.D., Emily Blood, M.S., Brett Hanscom, M.S., Harry Herkowitz, M.D., Frank Cammisa, M.D., Todd Albert, M.D., Scott D. Boden, M.D., Alan Hilibrand, M.D., Harley Goldberg, D.O., Sigurd Berven, M.D., and Howard An, M.D., for the SPORT Investigators*From the Departments of Orthopedics (J.N.W., E.B., B.H.), Community and Fam-ily Medicine (T.D.T., J.D.L., A.N.A.T.), and Medicine ( J.D.L., A.N.A.T.), Dartmouth Medical School, Hanover, NH, and Dart-mouth–Hitchcock Medical Center, Leba-non, NH; William H. Beaumont Hospital, Royal Oak, MI (H.H.); Hospital for Spe-cial Surgery, New York (F.C.); Rothman Institute at Thomas Jefferson University, Philadelphia (T.A., A.H.); Emory Spine Cen-ter, Emory University, Atlanta (S.D.B.); Kaiser Permanente, San Francisco (H.G.); University of California at San Francisco, San Francisco (S.B.); and Rush–Presbyte-rian–St. Luke’s Medical Center, Chicago (H.A.). Address reprint requests to Dr. Weinstein at the Dartmouth Institute for Health Policy and Clinical Practice, Depart-ment of Orthopedics, Dartmouth Medical School, 1 Medical Center Dr., Lebanon, NH 03756, or at [email protected].*Investigators in the Spine Patient Out-comes Research Trial (SPORT) are listed in the Appendix.N Engl J Med 2008;358:794-810.Copyright © 2008 Massachusetts Medical Society.A b s t r a c tBackgroundSurgery for spinal stenosis is widely performed, but its effectiveness as compared with nonsurgical treatment has not been shown in controlled trials.MethodsSurgical 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.ResultsA 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 ran-domized 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.ConclusionsIn the combined as-treated analysis, patients who underwent surgery showed sig-nificantly more improvement in all primary outcomes than did patients who were treated nonsurgically. (ClinicalTrials.gov number, NCT00000411.)Surgical v ersus Nonsurgical Ther apy for Spinal S tenosisn engl j med 358;8 www.nejm.org february 21, 2008795Spinal stenosis is a narrowing of the spinal canal with encroachment on the neu-ral structures by surrounding bone and soft tissue. Patients typically present with radicular leg pain or with neurogenic claudication (pain in the buttocks or legs on walking or standing that re-solves with sitting down or lumbar flexion). Spi-nal stenosis is the most common reason for lum-bar spine surgery in adults over the age of 65 years.1,2 Indications for surgery appear to vary widely, and rates of procedures vary by at least a factor of 5 across geographic areas.3,4 Radio-graphic evidence of stenosis is frequently asymp-tomatic; thus, careful clinical correlation between symptoms and imaging is critical.5,6A 2005 Cochrane review found that the pau-city and heterogeneity of evidence limited conclu-sions regarding surgical efficacy for spinal steno-sis. The trials comparing surgical with nonsurgical treatment were generally small and involved pa-tients both with and without degenerative spon-dylolisthesis.7-12 We know of no randomized trials of isolated spinal stenosis without degen-erative spondylolisthesis.In the Spine Patient Outcomes Research Trial (SPORT), we report on the 2-year outcomes of patients with spinal stenosis without degenera-tive spondylolisthesis to analyze the relative ef-ficacy of surgical versus nonsurgical treatment.M e t h o d sStudy DesignSPORT was an investigator-initiated study con-ducted in 11 states at 13 U.S. medical centers with multidisciplinary spine practices. The study included both a randomized cohort and a con-current observational cohort of patients who de-clined to undergo randomization.13-16 This de-sign allowed for improved generalizability of the findings.17 The ethics committee at each partici-pating institution approved a standardized pro-tocol. An independent data and safety monitoring board evaluated interim safety and efficacy out-comes at 6-month intervals.13-16,18 Stopping rules were provided on the basis of the alpha spending function of DeMets and Lan.19Patient PopulationAll patients had a history of neurogenic claudica-tion or radicular leg symptoms for at least 12 weeks and confirmatory cross-sectional imaging showing lumbar spinal stenosis at one or more levels; all patients were judged to be surgical can-didates. Patients with degenerative spondylolis-thesis were studied separately.16 Patients with lumbar instability (which was defined as transla-tion of more than 4 mm or 10 degrees of angular motion between flexion and extension on upright lateral radiographs) were excluded. The type of nonsurgical care before enrollment was not pre-specified but included physical therapy (68% of patients), epidural injections (56%), chiropractic (28%), the use of antiinflammatory drugs (55%), and the use