Intraoperative recording of parietal SEP can miss hemodynamic infarction during carotid endarterectomy: a case study

Serial recording of median nerve somatosensory evoked potentials (SEPs) provides reliable intraoperative information on critical lowering of brain perfusion which compares favorably with other monitoring methods. However, single-channel parietal SEP recording may not detect hemodynamic cerebral infarctions affecting the pre-rolandic area. Following left carotid endarterectomy for high-grade symptomatic stenosis in a 66-year-old male, predominantly motor hemiparesis and aphasia were detected which were largely reversible. Pre- and intraoperative SEPs were normal. Postoperative SEPs showed significant interhemispheric amplitude differences. Postoperative CT examinations demonstrated hemodynamic watershed-type infarctions. This rare complication of carotid endarterectomy was not detected by intraoperative single-channel parietal SEP monitoring.