Predicting conservative treatment failure in patients with lumbar disc herniation. Single center, case-control study

•Percentage of spinal canal compromise ratio was an independent predictor of surgery.•Each increase in that ratio by 1% above 23% augmented the chance of surgery by 6%.•Leg paresthesia increased the risk of surgery over 5 fold. The aim of this study was to identify independent predictors of conservative treatment failure in patients presenting due to lumbar disc herniation-associated low back pain and sciatica. This is a single institution, case-control study including 240 patients that were selected for microsurgical or conservative treatment due to lumbar disc herniation in a 2,5-year period. Bivariate and multivariate analyses were performed in order to identify independent predictors among demographic, clinical and radiographic factors. Statistically significant differences were observed between conservatively and surgically managed groups in bivariate analysis. Logistic regression models further revealed that leg paresthesia (p = 0,003; OR = 5,136) and percentage of spinal canal stenosis ratio (p