Lumbar Microdiscectomy in Obese Patients: A Multicenter Observational Study.

OBJECTIVE

To evaluate the association between obesity and outcomes after microdiscectomy for lumbar disc herniation.

METHODS

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.

RESULTS

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).

CONCLUSIONS

Although they had more minor complications, obese individuals experienced improvement after lumbar microdiscectomy for lumbar disc herniation similar to that of nonobese individuals.