Risk Factors for Reoperation in Patients Treated Surgically for Lumbar Stenosis: A Subanalysis of the 8-year Data From the SPORT Trial.

STUDY DESIGN: A retrospective subgroup analysis was performed on surgically treated patients from the lumbar spinal stenosis (SpS) arm of the Spine Patient Outcomes Research Trial (SPORT), randomized, and observational cohorts.

OBJECTIVE: To identify risk factors for reoperation in patients treated surgically for SpS and compare outcomes between patients who underwent reoperation with those who did not.

SUMMARY OF BACKGROUND DATA: SpS is one of the most common indications for surgery in the elderly; however, few long-term studies have identified risk factors for reoperation.

METHODS: A post-hoc subgroup analysis was performed on patients from the SpS arm of the SPORT, randomized and observational cohorts. Baseline characteristics were analyzed between reoperation and no-reoperation groups using univariate and multivariate analysis on data 8 years postoperation.

RESULTS: Of the 417 study patients, 88% underwent decompression only, 5% noninstrumented fusion, and 6% instrumented fusion. At the 8-year follow-up, the reoperation rate was 18%; 52% of reoperations were for recurrent stenosis or progressive spondylolisthesis, 25% for complication or other reason, and 16% for new condition. Of patients who underwent a reoperation, 42% did so within 2 years, 70% within 4 years, and 84% within 6 years. Patients who underwent reoperation were less likely to have presented with any neurological deficit (43% reop vs. 57% no reop, P = 0.04). Patients improved less at follow-up in the reoperation group (P < 0.001).

CONCLUSION: In patients undergoing surgical treatment for SpS, the reoperation rate at 8-year follow-up was 18%. Patients with a reoperation were less likely to have a baseline neurological deficit. Patients who did not undergo reoperation had better patient reported outcomes at 8-year follow-up compared with those who had repeat surgery.

LEVEL OF EVIDENCE: 2.