Neurophysiologic monitoring for treatment of upper lumbar disc herniation with percutaneous endoscopic lumbar discectomy: A case report on the significance of an increase in the amplitude of motor evoked potential responses after decompression and literature review

INTRODUCTION: Intraoperative neurophysiological monitoring (IONM) has been widely used in spinal surgery. There is lack of report about IONM for the treatment of upper lumbar disc herniation (HIVD) with percutaneous endoscopic lumbar discectomy (PELD), the relationship between an immediate increase in amplitude of intraoperative MEP after decompression and improvement of the treated levels is rarely studied. Here we reported a surgical case in which an elderly patient with HIVD underwent PELD with IONM and there was a distinct increase in the amplitude of MEP after decompression, showing an immediate improvement of the treated levels. PRESENTATION OF CASE: A 60-year-old male patient underwent PELD to remove the large disc fragments extruded upward into L2-3 intervertebral space. The nucleus pulposus was successfully removed and an increase in the amplitude of MEP responses after decompression was observed. Pain was alleviated immediately after operation and no complication and recurrence was observed at 1 year follow-up. DISCUSSION: This is a surgical case of PELD for HIVD with IONM. In this study, we reviewed related studies on PELD for HIVD with IONM and discussed the relationship between an immediate increase in amplitude of intraoperative MEP and the outcomes of the treated level. CONCLUSION: We conclude an immediate increase in amplitude of MEP after decompression can be considered as an improvement of the treated levels. IONM can not only be used to prevent the risk of neurological injury in PELD for HIVD, but also be helpful to surgeon to judge the efficacy of decompression via an immediate increase in amplitude of intraoperative MEP.