Long-Term Results of Surgery Compared with Nonoperative Treatment for Lumbar Degenerative Spondylolisthesis in the Spine Patient Outcomes Research Trial (SPORT)

Abstract

Study Design

Randomized trial with a concurrent observational cohort study

Objective

To compare eight-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 four years. This study sought to further determine the long-term (8-year) outcomes.

Methods

Surgical candidates with DS from thirteen centers with at least twelve 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 six weeks, three months, six months and yearly up to eight years.

Results

Data were obtained for 69% of the randomized cohort and 57% of the observational cohort at the eight-year follow up. Intent-to-treat analyses of the randomized group were limited by high levels of nonadherence to the randomized treatment. As-treated 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 eight years. Outcomes were similar among patients treated with uninstrumented posterolateral fusion, instrumented posterolateral fusion, and 360° fusion.

Conclusion

For patients with symptomatic DS, patients who received surgery had significantly greater improvements in pain and function compared to nonoperative treatment through eight years of follow-up. Fusion technique did not affect outcomes.