The comparison of somatosensory evoked potential and motor evoked potential monitoring for cerebral ischemia during carotid endarterectomy

Objective The objective of this retrospective study is to investigate the relationship between the postoperative cerebral ischemia and somatosensory evoked potential(SSEP) or motor evoked potential(MEP) monitoring, during carotid endarterectomy. Methods Eighty-four patients undergoing carotid endarterectomy(CEA) undergoing general anesthesia with monitoring of bilateral SSEP and MEP were retrospectively reviewed between September 2011 and July 2014. The rates of successful assessment of SSEP and MEP and changes in SSEP and MEP monitoring were investigated. Postoperative cerebral ischemia assessed by CT and the correlation between the significant changes of intraoperative evoked potential and postoperative neurological dysfunction was studied. Results Multimodal SSEP monitoring was achieved in 81 patients, whereas MEP was recorded in 68 cases. Significant SSEP changes occurred in 11 patients and MEP in 29 patients. Five patients showed permanent postoperative neurological deficit. Significant SSEP changes were related with postoperative neurological dysfunction(P 0.05). Conclusions Our data suggest that SSEP were significantly associated with postoperative cerebral ischemia. However, the small number of patients limits the conclusiveness of these findings. MEP monitoring could not prevent a postoperative motor deficit in all patients. Key words: Carotid endarterectomy; Somatosensory evoked potential; Motor evoked potential; Neurological dysfunction