Neuroimaging study of interlaminar percutaneous endoscopic lumbar discectomy

Objective To utilize the magnetic resonance neurography (MRN) as a feasible tool for measuring the anatomical parameters of lumbar spinal nerves, and further to evaluate the neuro-safety of interlaminar percutaneous endoscopic lumbar discectomy. Methods Thirty healthy adult volunteers without significant history of low back pain or lumbar deformity were selected in our hospital from September 2016 to December 2016. All subjects accepted MRN. The nerve roots of L2-S1 were measured at the starting point of dural sac, and the angles between nerve roots and dural sac were measured. The distances between L2-L5 nerve roots and the edge of ipsilateral dural sac were measured and analyzed statistically. Results All MRN showed a gradual increase in the origin of the nerve roots from L2 to S1. The origin of the root was found to be below the corresponding disc for the L2 to L4 roots. There were 70% of the L5 roots originated below the L4/5 disc, 26.7% at the L4/5 disc, and 3.3% above the L4/5 disc; about 70% of the S1 roots originated above the L5/S1 disc. There were no statistically significant differences in the angles between dural sac and both left and right nerve roots (P>0.05). The angels between the nerve root and the dural sac from L5 and S1 was smaller than those from L2, L3, and L4 (P 0.05). Conclusion MRN is a feasible tool to measure the anatomical parameters of the lumbar spinal nerve, and there is a safe neurological area of the percutaneous endoscopic lumbar discectomy through the interlaminar approach. Key words: Magnetic resonance neurography; Interlaminar approach; Percutaneous endoscopic lumbar discectomy