Lumbar Microdiscectomy in Obese Patients: A Multicenter Observational Study.

Abstract

To evaluate the association between obesity and outcomes after microdiscectomy for lumbar disc herniation. The primary outcome measure was change in Oswestry Disability Index (ODI) at 1 year after surgery. Obesity was defined as body mass index (BMI) ≥30. Prospective data were retrieved from the Norwegian Registry for Spine Surgery. We enrolled 4932 patients, 4018 nonobese and 914 obese. For patients with complete 1-year follow-up (n = 3381) the mean improvement in ODI was 31.2 points (95% confidence interval 30.4-31.9, P < 0.001). Improvement in ODI was 31.4 points in nonobese and 30.1 points in obese patients (P = 0.182). Obese and nonobese patients were as likely to achieve a minimal clinically important difference (84.2 vs. 82.7%, P = 0.336) in ODI (≥10 points improvement). Obesity was identified as a negative predictor for ODI improvement in a multiple regression analysis (BMI 30-34.99; P < 0.001, BMI ≥35; P = 0.029). Obese and nonobese patients experienced similar improvement in Euro-Qol-5 scores (0.48 vs. 0.49 points, P = 0.441) as well as back pain (3.7 vs. 3.5 points, P = 0.167) and leg pain (4.7 vs. 4.8 points, P = 0.654), as measured by the Numeric Rating Scale. Duration of surgery was shorter for nonobese patients (55.7 vs. 65.3 minutes, P ≤ 0.001). Nonobese patients experienced fewer complications compared with obese patients (6.1% vs. 8.3%, P = 0.017). Obese patients had slightly longer hospital stays (2.0 vs. 1.8 days, P = 0.004). Although they had more minor complications, obese individuals experienced improvement after lumbar microdiscectomy for lumbar disc herniation similar to that of nonobese individuals.