Reoperation for Recurrent Intervertebral Disc Herniation in the Spine Patient Outcomes Research Trial Analysis of Rate, Risk Factors, and Outcome

Study Design. This study was a post-hoc subgroup analysis of prospectively collected data in the Spine Patient Outcomes Research Trial (SPORT). Objective. The aim of this study was to determine the risk factors for and to compare the outcomes of patients undergoing revision disc excision surgery in SPORT. Summary of Background Data. Risk factors for reherniation and outcomes after revision surgery have not been well-studied. This information is critical for proper patient counseling and decision-making. Methods. Patients who underwent primary discectomy in the SPORT intervertebral disc herniation cohort were analyzed to determine risk factors for undergoing revision surgery. Risk factors for undergoing revision surgery for reherniation were evaluated using univariate and multivariate analysis. Primary outcome measures consisted of Oswestry Disability Index (ODI), the Sciatica Bothersomeness index (SBI), and the Short Form 36 (SF-36) at 6 weeks, 3 months, 6 months, and yearly to 4 years. Results. Of 810 surgical patients, 74 (9.1%) received revision surgery for reherniation. Risk factors for reherniation included: younger age (hazard ratio [HR] 0.96 [0.94-0.99]), lack of a sensory deficit (HR 0.61 [0.37-0.99]) lack of motor deficit (HR 0.54 [0.32-0.91]), and higher baseline ODI score (HR 1.02 [1.01-1.03]). The time-adjusted mean improvement from baseline to 4 years was less for the reherniation group on all outcome measures (Bodily Pain Index [BP] 39.5 vs. 44.9, P = 0.001; Physical Function Index [PF] 37.1 vs. 44.5, P< 0.001; ODI 33.9 vs. 38.3, P< 0.001; SBI 8.7 vs. 10.5, P< 0.001). At 4 years, only SBI (-9 vs. -11.4, P = 0.002) was significantly lower in the reherniation group. Conclusion. Younger patients with higher baseline disability without neurological deficit are at increased risk of undergoing revision surgery for reherniation. Those considering revision surgery for reherniation will likely improve significantly following surgery, but possibly not as much as with primary discectomy.