Assessment: intraoperative neurophysiology. Report of the Therapeutics and Technology Assessment Subcommittee of the American Academy of Neurology.

Experience to date in both humans and controlled animal research studies substantiates that several electrophysiology tests and monitoring techniques are safe and efficacious, to a variable degree, as commonly applied in the operating room for the following procedures: EEG or SEP to monitor for cerebral ischemia; ECoG and SEP sensory cortex identification to define the limits of cortical resection; SEP spinal cord monitoring; BAEP and cranial nerve EMG monitoring during posterior fossa procedures; functional localization of cortex with direct cortical stimulation in expert hands; and EMG and compound muscle and nerve action potential measurements of various peripheral nervous system structures. All these techniques need to be applied by a well-trained, knowledgeable physician-neurophysiologist or personnel directly under his or her supervision. Clinical situations need to be chosen carefully, avoiding those in which the nervous system is only at low risk.