Impact of anesthesia on transcranial electric motor evoked potential monitoring during spine surgery: A review of the literature

Object: Transcranial motor evoked potential (TcMEP) monitoring is frequently used in complex spinal surgeries to prevent neurological injury. Anesthesia, however, can significantly affect the reliability of TcMEP monitoring. Understanding the impact of various anesthetic agents on neurophysiological monitoring is therefore essential. Methods: A literature search of the National Library of Medicine database was conducted to identify articles pertaining to anesthesia and TcMEP monitoring during spine surgery. Twenty studies were selected and reviewed. Results: Inhalational anesthetics and neuromuscular blockade have been shown to limit the ability of TcMEP monitoring to detect significant changes. Hypothermia can also negatively affect monitoring. Opioids, however, have little influence on TcMEPs. Total intravenous anesthesia regimens can minimize the need for inhalational anes thetics. Conclusions: In general, selecting the appropriate anesthetic regimen with maintenance of a stable concentration of inhalational or intravenous anesthetics optimizes TcMEP monitoring.