MRI Radiological Predictors of Requiring Microscopic Lumbar Discectomy After Lumbar Disc Herniation

Abstract

Study Design: Retrospective cohort study. Objective: To investigate radiological differences in lumbar disc herniations (herniated nucleus pulposus [HNP]) between patients receiving microscopic lumbar discectomy (MLD) and nonoperative patients. Methods: Patients with primary treatment for an HNP at a single academic institution between November 2012 to March 2017 were divided into MLD and nonoperative treatment groups. Using magnetic resonance imaging (MRI), axial HNP area; axial canal area; HNP canal compromise; HNP cephalad/caudal migration and HNP MRI signal (black, gray, or mixed) were measured. T test and chi-square analyses compared differences in the groups, binary logistic regression analysis determined odds ratios (ORs), and decision tree analysis compared the cutoff values for risk factors. Results: A total of 285 patients (78 MLD, 207 nonoperative) were included. Risk factors for MLD treatment included larger axial HNP area (P 70.52 mm2 (75.5%, P =.01) and HNP canal compromise >20.0% (71.1%, P =.05) cutoffs. MLD risk in patients with cephalad/caudal migration >6.8 mm (40.5% alone) increased when combined with axial HNP area and HNP canal compromise (52.4%, 50%; P