Wikipedia defines Intraoperative neurophysiological Monitoring as the following:
Intraoperative neurophysiological monitoring (IONM) or intraoperative neuromonitoring is the use of electrophysiological methods such as electroencephalography (EEG), electromyography (EMG), and evoked potentials to monitor the functional integrity of certain neural structures (e.g., nerves, spinal cord and parts of the brain) during surgery. Neuromonitoring employs various electrophysiologic modalities, such as extracellular single unit and local field recordings, SSEP, transcranial electrical motor evoked potentials (TCeMEP), EEG, EMG, and auditory brainstem response (ABR). For a given surgery, the set of modalities used depends in part on which neural structures are at risk and are ordered by your surgeon. IONM techniques have significantly reduced the rates of morbidity and mortality without introducing additional risks and therefore reduce health care costs.
There are 2 main reasons that a surgeon will utilize IONM during surgery:
- To reduce the risk to the patient of iatrogenic damage, which is damage induced inadvertently by a physician or surgeon during medical treatment or procedure, to the nervous system.
- To provide functional guidance to the surgeon and anesthesiologist.
To accomplish these objectives, the Interpreting physician/oversight physician is a part of the surgical team and obtains and interprets both triggered and spontaneous electrophysiologic signals from the patient throughout the course of the operation via a remote real-time computer connection which is being maintained and monitored by an IONM technician inside the OR. Patients who benefit from IONM are those undergoing operations involving the nervous system or which pose risk to its anatomic or physiologic integrity. The interpreting physician can thus observe and document the electrophysiologic signals in real-time in the operating area during the surgery. The signals change according to various factors, including anesthesia, tissue temperature, surgical stage, and tissue stresses. Differentiating the signal changes along the timeline of surgical stages is the joint task of the surgical triad: surgeon, anesthesiologist, and interpreting physician.