Scope

Intraoperative neuromonitoring in generaldoes not strive to be diagnostic.  Itsfunction is to assess changes during specific stages of a surgical procedure.

Environment

Intraoperative neuromonitoring is performedin an electrically hostile environment. Special equipment and techniques are used to minimize the effects of 60cycle, electrocautery, radiofrequency, carrier and other electrical noise fromthe operating room.

Anesthesia

Anesthesia greatly affects the ability torecord reproducible signals during surgery. For example:

.Gas anesthesia causes changes in SSEPamplitude and latency in a dose-dependant, but non-linear fashion

.High levels of pentothal or propofolimpede the ability to record EEG

.The level of muscle relaxation must becarefully titrated in order to obtain meaningful EMG or evoked EMG activity

.Low doses of nitrous oxide or propofolobliterate certain types of motor evoked potentials