Impact of Intraoperative Neurophysiological Monitoring on Supratentorial Meningioma Surgery: A Systematic Review

Objectives: Our objective was to systematically evaluate the role of intraoperative neurophysiological monitoring (IONM) in supratentorial meningioma surgery, focusing on intraoperative changes, surgical decision-making, and postoperative neurological outcomes. Methods: A PRISMA-guided systematic review was conducted across PubMed, Scopus, and Cochrane databases. Nine studies, including 576 supratentorial meningioma (STM) cases identified across the source cohorts, were analyzed. Data extraction included study design, tumor location, monitoring modalities, intraoperative neurophysiological changes, and postoperative outcomes. Risk of bias was assessed using ROBINS-I, the JBI Critical Appraisal Checklist, or QUADAS-2, according to study design. Results: IONM modalities varied widely and included motor and somatosensory evoked potentials, cortical stimulation, and electromyography. Substantial heterogeneity was observed. Postoperative deficits occurred in both monitored and unmonitored patients (5.2-66%), including cases with preserved intraoperative signals, suggesting false negatives. IONM influenced intraoperative decision-making in selected cases, particularly for tumors near motor areas. However, its impact on postoperative outcomes remains unclear. Conclusions: Intraoperative motor cortex identification was the most consistently reported finding with a surgical impact. Available data from the literature are inconclusive about the role of IONM in reducing postoperative neurological morbidity.