Surgery for Herniated Lumbar Disc in Daily Tobacco Smokers: A Multicenter Observational Study.

OBJECTIVE:To compare clinical outcomes at 1 year following single-level lumbar microdiscectomy in daily tobacco smokers and nonsmokers. METHODS:Data were collected through the Norwegian Registry for Spine Surgery. The primary endpoint was a change in the Oswestry Disability Index (ODI) at 1 year. Secondary endpoints were change in quality of life measured with EuroQol 5 Dimensions (EQ-5D), leg and back pain measured with a numerical rating scale (NRS), and rates of surgical complications. RESULTS:A total of 5514 patients were enrolled, including 3907 nonsmokers and 1607 smokers. A significant improvement in ODI was observed for the entire cohort (mean, 31.1 points; 95% confidence interval [CI], 30.4-31.8; P < 0.001). Nonsmokers experienced a greater improvement in ODI at 1 year compared with smokers (mean, 4.1 points; 95% CI, 2.5-5.7; P < 0.001). Nonsmokers were more likely to achieve a minimal important change (MIC), defined as an ODI improvement of ≥10 points, compared with smokers (85.5% vs. 79.5%; P < 0.001). Nonsmokers experienced greater improvements in EQ-5D (mean difference, 0.068; 95% CI, 0.04-0.09; P < 0.001), back pain NRS (mean difference, 0.44; 95% CI, 0.21-0.66; P < 0.001), and leg pain NRS (mean difference, 0.54; 95% CI, 0.31-0.77; P < 0.001). There was no difference between smokers and nonsmokers in the overall complication rate (6.2% vs. 6.7%; P = 0.512). Smoking was identified as a negative predictor for ODI change in a multiple regression analysis (P < 0.001). CONCLUSIONS:Nonsmokers reported a greater improvement in ODI at 1 year following microdiscectomy, and smokers were less likely to experience an MIC. Nonetheless, significant improvement was also found among smokers.