IONM in Vascular Surgery
Introduction
Carotid endarterectomy
A carotid endarterectomy is a procedure to remove plaque buildup from the carotid artery, which supplies the brain with blood and oxygen. The carotid arteries lie on both sides of the neck and each branches into the internal and external carotid arteries. The region where the internal and external carotid arteries branch (or bifurcate) is susceptible to plaque buildup. The procedure involves making a small incision in the carotid artery and removing the plaque buildup, which is categorized by the degree of stenosis (mild, moderate, severe, total occlusion) and diameter of arterial reduction (<50%, 50-69%, 70-99%, 100%). The procedure requires a bypass shunt or artery clamp in order to work on the region containing the plaque buildup. A bypass shunt is commonly used to maintain cerebral blood flow but increases the risk of embolic stroke if plaque, air or debris is released in the vessels during shunt placement.
EEG and SSEPs are the most common modalities used to monitor ischemic events in the brain during a carotid endarterectomy.