Intraoperative Neurophysiological Monitoring for Intradural Extramedullary Spinal Tumors Excision

Background: Spinal neurosurgery often uses intraopera-tive neurophysiological monitoring (IONM), but its efficacy for IDEM spinal tumors is less established. Technological ad-vancements in imaging, neuromonitoring, and minimally in-vasive techniques are being used to improve functional results and minimize complications. A comprehensive clinical and radiological evaluation was performed. Somatosensory evoked potentials (SEPs) and motor evoked potentials (MEPs) moni-toring were performed during surgery. Postoperative neurolog-ical outcome was evaluated immediately after surgery and at 6 months follow-up. Aim of Study: To evaluate the immediate and six-month outcomes of IDEM spinal tumor surgery using IONM in pa-tients with or without neurological deficits. Patients and Methods: This prospective study was carried out on 30 patients with IDEM spinal tumors who underwent surgery with IONM. Results: The study involved 30 IDEM tumor patients who underwent IONM surgery, with the majority being females (63.33%) and most having preoperative grade I Modified Mc-Cormick scale (MMS) scores (43.33%). The surgery involved total laminectomy in 20 patients (66.67%), total laminectomy with fixation in 6 (20%), and partial laminectomy in 4 (13.33%) patients. Histopathological findings revealed meningioma in 36.67% of patients, followed by schwannoma in 13.33%, neu-rofibroma in 23.33%, ependymomas in 16.67%, dermoid cysts in 6.67%, and hemangiopericytoma in 3.33%. In a study of 24 patients without deficit, 79.16% had stable IONM, while 20.83% experienced transient minor changes before recovery and continued surgery. In the deficit group, 66.67% experienced minor changes, followed by deterioration and surgery stops in 33.33% of patients. The study found a correlation between the MMS preoperatively, histopathological findings, and hospital stay for both groups with and without deficitafter a 6-months follow-up. Sensitivity decreased from 66.7% to 33.3% at 6 months, specificity from 92.6% to 91.7%, and Accuracy from 90.0% to 80.0% at 6 months. NPV worsene from 96.2% to 84.6%. Mc Nemar test (1 and 0.687), and Kappa tests 0.687 and 0.286, respectively. The rise in false negatives contributed to the decline in accuracy, indicating a need for improved test reliability. Conclusion: IONM techniques like SSEPs, MEPs, EMG, and D-waves are increasingly used in spinal procedures to pre-vent neurological complications. It accurately predicts immedi-ate neurological deficit after IDEM spinal tumor excision, but its predictive value for deficit 6 months post-surgery is lower.