Intraoperative Neurophysiological Monitoring in Neurosurgery

Intraoperative neurophysiological monitoring (IONM) refers to the use of different neurophysiological techniques for functional assessment and real-time monitoring of at-risk neural networks during surgery, in order to detect early and potentially reversible neurophysiological dysfunctions and guide changes in the management of surgery and/or anesthesia. IONM has been extensively used to assess the function of the brain, brainstem, spinal cord, cranial nerves, and peripheral nerves during neurosurgery, and is now an essential tool for many surgical procedures. IONM protocol is chosen based on the particular type of surgery and inherent risks. For IONM to be effective and reliable, close collaboration is necessary between all the actors that make up the monitoring team, generally composed of a clinical neurophysiologist, a neurophysiology technician, a neurosurgeon, and an anesthesiologist. The close interaction between the team personnel allows the correct interpretation of the alterations of the monitored signals, necessary to distinguish changes related to surgical, anesthetic, and physiological factors.