Abstract

Background: Surgery is the preferred treatment for symptomatic intramedullary lesions. Intraoperative neurophysiological monitoring (IONM) has recently emerged as a crucial tool in spinal surgery, enhancing safety through real-time assessment of spinal cord function. Its use is particularly beneficial during intramedullary tumor resection, helping to reduce the risk of neurological impairment and improve postoperative outcomes. Objective: Our study aims to evaluate the efficacy and outcomes of intraoperative neurophysiological monitoring for intramedullary tumor resection surgery in Vietnam and to identify some key predictive factors for tumor resectability. Methods: A prospective study on 41 patients treated with neurosurgery using multimodal intraoperative neurophysiological monitoring between January 2022 and February 2024 at the Neurosurgery Center, Hanoi, Viet Nam. Results: Gross total tumor resection was achieved in 26/41 patients (63.4%) with the mean tumor length was 49.9 mm. Among them, 21 cases (51.2%) were ependymoma, 15 cases (36.6%) were diffuse gliomas and 5 cases (12.2%) were other types (including hemangioblastoma, and metastases). Early outcomes assessed at 6 months using the modified McCormick Scale (MCS) revealed that 23.1 % showed no change, 76.9% patients demonstrated improvement. Univariate demonstrated intraoperative motor evoked potentials (MEPs) changes, tumor length and tumor transverse diameter were predictive factors for the resectability; preoperative McCormick Scale and somatosensory evoked potentials (SSEPs) changes were predictors for postoperative outcomes. Multivariate analysis revealed that tumor length was the only independent factor predicting tumor resectability. Conclusion: Our study demonstrated the efficacy of IONM in improving surgical outcomes for patients undergoing intramedullary tumor resection. The outcomes of patients with intramedullary tumors post-surgery with IONM were significantly affected by the preoperative McCormick Scale and SSEPs changes during surgery. Predictive factors for resectability were tumor size in preoperative Magnetic Resonance Imaging (MRI) and intraoperative MEPs changes.

Key words: Intraoperative neurophysiological monitoring, Somatosensory evoked potential.