Objective To investigate the value of intraoperative neurophysiological monitoring in surgery for cauda equina and conus medullaris lesions.Methods The clinical data of 110 patients with cauda equina and conus medullaris lesions were analyzed retrospectively. Microsurgery was performed for all lesions under intraoperative neurophysiological monitoring. Somatosensory evoked potential (SEP) and motor evoked potential (MEP) were used to monitor spinal cord function, and electromyography was used to determine the extent of tumor resection.Results A total of 92 patients (83.6%) received complete resection of lesions under microscope, and 18 patients (16.4%) received subtotal or partial resection. Postoperative follow-up was performed for 1-58 months, and physical examination of the nervous system and Japanese Orthopaedic Association scoring showed that 102 patients (92.8%) had improvement in the function of spinal nerves, 4 patients (3.6%) had no changes, and 4 patients (3.6%) had reduced function of spinal nerves. As for comparison of the latency period and amplitude of SEP and the latency period of MEP before and after the resection of lesions, the patients with improvement and reduction in the function of spinal nerves had significant changes in the indicators for neurophysiological monitoring (P<0.05), while the patients with no changes in the function of spinal nerves had no significant changes in these indicators (P>0.05); the changes in the indicators for neurophysiological monitoring were basically consistent with postoperative improvement in the function of spinal nerves.Objective Intraoperative neurophysiological monitoring can monitor the functional integrity of spinal nerves, and its combination with microsurgical techniques can significantly increase the total resection rate of cauda equina and conus medullaris lesions, reduce postoperative complications, and improve the efficacy and safety of surgery.