Does Greater Body Mass Index Increase the Risk for Revision Procedures Following a Single-Level Minimally Invasive Lumbar Discectomy?

STUDY DESIGN Retrospective analysis of a prospectively maintained surgical registry. OBJECTIVE To examine the association between body mass index (BMI) and the risk for undergoing a revision procedure following a single-level minimally invasive (MIS) lumbar discectomy (LD). SUMMARY OF BACKGROUND DATA Studies conflict as to whether greater BMI contributes to recurrent herniation and the need for revision procedures following LD. Patients and surgeons would benefit from knowing whether greater BMI is a risk factor to guide the decision whether to pursue an operative versus non-operative treatment. METHODS Patients undergoing a single-level MIS LD were retrospectively identified in our institution's prospectively maintained surgical registry. BMI was categorized as normal weight (<25 kg/m), overweight (25-30 kg/m), obese (30-40 kg/m), or morbidly obese (≥40 kg/m). Multivariate analysis was used to test for association with undergoing a revision procedure during the first 2 postoperative years. The model was demographics, comorbidities, and operative level. RESULTS A total of 226 patients were identified. Of these, 56 (24.8%) were normal weight, 80 (35.4%) were overweight, 66 (29.2%) were obese, and 24 (10.6%) were morbidly obese. A total of 23 patients (10.2%) underwent a revision procedure in the first 2 postoperative years. The 2-year risk for revision procedure was 1.8% for normal weight patients, 12.5% for overweight patients, 9.1% for obese patients, and 25.0% for morbidly obese patients. In the multivariate-adjusted analysis model, BMI category was independently associated with undergoing a revision procedure (P = 0.038). CONCLUSION These findings indicate that greater BMI is an independent risk factor for undergoing a revision procedure following a LD. These findings conflict with recent studies that have found no difference between obese and non-obese patients in regards to risk for recurrent herniation and/or revision procedures. Patients with greater BMI undergoing LD should be informed they could have an elevated risk for revision procedures. LEVEL OF EVIDENCE 4.