The Effect of Body Mass Index on Surgical Outcomes Following Aseptic Short-Segment Revision Lumbar Fusions: A Retrospective Study.

Abstract

This study investigated the association among preoperative body mass index (BMI) and surgical outcomes, reoperation rate, and 1-year patient-reported outcome measures (PROMs) following 1-3 level revision lumbar fusion. Patients who underwent a 1-3 level revision lumbar fusion from 2011-2021 were included. Patients were grouped into BMI classes: normal (18.5-24.99), overweight (25.0-29.99), obese class 1 (30.0-34.99), and obese class 2+ (≥35.0). Demographics, surgical characteristics, 1-year reoperations, 90-day readmissions, and 1-year PROMs were compared between cohorts. PROMs included the Short Form-12 Physical Component Score, Mental Component Score, Oswestry Disability Index, Visual Analog Scale Back pain score, and Visual Analog Scale Leg pain score. In total, 743 patients were identified: 115 normal weight, 254 overweight, 206 obese class 1, and 168 obese class 2+. Operative time (P = 0.007) and length of stay (LOS) (P = 0.002) were longer in patients with higher BMI. Multivariate regression demonstrated obese class 2+ was independently associated with longer operative times (estimate: 32.43; P = 0.008) and LOS (estimate: 0.68; P = 0.044). There were no differences in readmission (P = 0.285) or reoperation rates (P = 0.727). All patients received a similar benefit between preoperative and 1-year PROMs. While more obese revision lumbar fusion patients experienced longer operative times and LOS, these patients ultimately experienced similar improvements from surgical intervention at 1 year postoperatively. Regardless of BMI class, all patients had comparable rates of readmission within 90 days and reoperation. These findings support previous lumbar fusion literature and suggest an indicated revision lumbar fusion in higher BMI class patients does not lead to further reoperations or worse PROMs.