Intraoperative neuromonitoring (IONM) plays a critical role in assessing neural integrity and guiding surgical decision-making. The effects of traditional anesthetic agents on IONM are well-established, though the impact of novel anesthetics and adjunct analgesics remains unclear. This scoping review aims to evaluate the effects of novel anesthetic and adjunct analgesic agents on somatosensory evoked potentials (SSEPs) and motor evoked potentials (MEPs) in the intraoperative setting. A comprehensive literature search was conducted using Medline, Cochrane Central, CINAHL, Scopus, LILACS, and Embase, from inception to February 2025. Randomized controlled trials, observational studies, and case series assessing the effects of lidocaine, ketamine, dexmedetomidine, methadone, magnesium, gabapentinoids, xenon, and remimazolam on IONM were included in the review. Backward citation searching was also performed on the included studies. A total of 53 studies met inclusion criteria, comprising 30 randomized and 23 nonrandomized studies. Lidocaine, when administered within analgesic dosing, had minimal impact on SSEPs and MEPs. Ketamine exhibited augmentative, neutral, or suppressive effects on IONM, which appeared to be dependent on the dosing regimen. Dexmedetomidine demonstrated mixed effects on IONM, potentially due to dose-dependent hemodynamic alterations and its unique pharmacokinetic properties. Methadone and magnesium showed minimal impact on IONM, while xenon was associated with clinically relevant suppression of evoked potentials. Remimazolam appeared to maintain neuromonitoring integrity at clinically relevant doses. The effects of novel anesthetic and adjunct analgesic agents on IONM are variable and dose-dependent, necessitating individualized anesthetic strategies. Future research should focus on larger randomized trials with standardized protocols to better define their roles in a neuromonitoring-compatible anesthetic regimen.
Ma et al. (Tue,) studied this question.