Long-Term results of surgery compared with nonoperative treatment for lumbar degenerative spondylolisthesis in the spine patient outcomes research trial (SPORT)

Study Design. Randomized trial with a concurrent observational cohort study. Objective. To compare 8-year outcomes between surgery and nonoperative care and among different fusion techniques for symptomatic lumbar degenerative spondylolisthesis (DS). Summary of Background Data. Surgical treatment of DS has been shown to be more effective than nonoperative treatment out to 4 years. This study sought to further determine the longterm (8-year) outcomes. Methods. Surgical candidates with DS from 13 centers with at least 12 weeks of symptoms and confirmatory imaging were offered enrollment in a randomized controlled trial (RCT) or observational cohort study (OBS). Treatment consisted of standard decompressive laminectomy (with or without fusion) versus standard nonoperative care. Primary outcome measures were the Short Form-36 (SF-36) bodily pain and physical function scores and the modified Oswestry Disability Index at 6 weeks, 3 months, 6 months, and yearly up to 8 years. Results. Data were obtained for 69% of the randomized cohort and 57% of the observational cohort at the 8-year follow up. Intent-To-Treat analyses of the randomized group were limited by high levels of nonadherence to the randomized treatment. Astreated analyses in the randomized and observational groups showed significantly greater improvement in the surgery group on all primary outcome measures at all time points through 8 years. Outcomes were similar among patients treated with uninstrumented posterolateral fusion, instrumented posterolateral fusion, and 3608 fusion. Conclusion. For patients with symptomatic DS, patients who received surgery had significantly greater improvements in pain and function compared with nonoperative treatment through 8 years of follow-up. Fusion technique did not affect outcomes.