Obesity and Workers’ Compensation in the Setting of Minimally Invasive Lumbar Decompression

Abstract

To investigate the influence of body mass index (BMI) on perioperative outcomes, postoperative patient-reported outcome measures (PROMs), and minimal clinically important difference (MCID) achievement among workers' compensation (WC) claimants undergoing minimally invasive lumbar decompression (MIS-LD). WC patients diagnosed with herniated nucleus pulposus undergoing single-level MIS-LD were identified. Patients were divided into 3 groups: Non-obese (<30 kg/m2), Obese I (≥30 and <35 kg/m2), and Obese II/III (≥35 kg/m2). PROMs were collected preoperatively and at 6 weeks, 12 weeks, 6 months, 1 year, and 2 years postoperatively. The predictive influence of BMI grouping on mean PROM scores was computed using simple linear regression. To compare PROMs between groups, post hoc pairwise comparisons of adjusted means were utilized. MCID achievement was compared between groups with χ2 analysis. A total of 81 patients were in the Non-obese cohort, and 43 and 45 in the Obese I and Obese II/III cohorts, respectively. Visual analog scale (VAS) leg, Oswestry Disability Index (ODI), and 12-Item Short Form Physical Composite Score (SF-12 PCS) were worse in the Obese I cohort at 12 weeks, and SF-12 PCS was lower in the Obese I vs. Obese II/III subgroup analysis (P ≤ 0.045, all). MCID achievement rates for ODI were higher for the Non-obese group at 12 weeks and overall (P ≤ 0.049, both). MCID attainment for VAS back was higher among the Non-obese cohort at 6-weeks (P= 0.022). Patients with higher levels of obesity were more likely to experience longer length of stay and delayed discharge following MIS-LD. Increasing BMI was generally not a significant predictor of postoperative pain, disability, or physical health PROMs at most timepoints. MCID achievement rates for disability relief were significantly higher for non-obese patients.