Accuracy of intraoperative neurophysiological monitoring in predicting postoperative neurological decline in intradural extramedullary spinal tumor surgery: a systematic review and meta-analysis

The role of intraoperative neurophysiological monitoring (IONM) in intradural extramedullary (IDEM) tumor surgery remains unestablished. Therefore, the purpose of this study was to systematically review and meta-analyze the recent literature on the accuracy of IONM in the resection of IDEM tumors.The study was conducted according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. The PubMed, Embase, and Cochrane databases were searched for English-language papers published from inception until February 19, 2025. The study was found eligible if it reported the complete data on the accuracy of motor evoked potentials (MEPs), somatosensory evoked potentials (SSEPs), D-wave monitoring, or multimodal IONM (mIONM - defined as a combination of more than one of the abovementioned modalities) in patients with IDEM tumors. Each modality's accuracy was evaluated using the Hierarchical Summary Receiver Operating Characteristic (HSROC) curve for predicting short-term (immediate postoperative) and long-term postoperative deficits (minimum of 3 months after discharge).From a total of 3220 papers, 16 studies met the eligibility criteria. Additionally, one study was found based on references analysis, resulting in the inclusion of 17 papers. MEPs significantly predicted the occurrence of both short-term (AUROC = 0.72; p < 0.0001) and long-term (AUROC = 0.91; p = 0.006) new motor deficits. Conversely, D-wave failed to accurately predict motor deficits (AUROC = 0.83; p = 0.1094, and AUROC = 0 in the short- and long-term observation, respectively). Similarly, SSEPs showed low accuracy in predicting short-term (AUROC = 0.55; p = 0.7461) and long-term (AUROC = 0.53; p = 0.3953) sensory deficits. Conversely, mIONM was found to accurately predict short-term (AUROC = 0.75; p = 0.001) and long-term (AUROC = 0.70; p = 0.005) new neurological deficits.MEPs and mIONM constitute the sole modalities that can accurately predict motor and neurological deficits, respectively. Contrarily, the low sensitivity of SSEPs for predicting sensory deficits underlines its efficacy in IDEM tumor surgery. Although D-wave did not achieve satisfactory accuracy, its application seems reasonable to prevent permanent motor deficits.