Neurophysiological intraoperative monitoring in spine surgery

Abstract

Intraoperative neurophysiological monitoring (IONM) makes it possible to determine the status of neurological function during surgery. It guides the surgeon and minimises the risk of injury. This paper describes the different techniques available for IONM in spine surgery (somatosensory evoked potentials, motor evoked potentials, neurography, electromyography, reflexes and dermatomic evoked potentials), which neurophysiologists employ depending on the nerve structures at risk. In order for monitoring to be successful, coordination between all members of the surgical team is essential. In the event of IONM registering alterations, the neurophysiologist must first check the integrity of the recording system. The anaesthetist should then assess blood pressure, oxygen levels, ventilation and haematocrit values, and revert recent anaesthetic changes. Finally, the surgeon must stop the procedure and try to determine the cause of the event, and correct it if possible.