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.