Vagus nerve neuromonitoring during carotid endarterectomy.

To determine the causes and site(s) of nerve injury and to identify potential predictors of vocal fold paralysis (VFP) after carotid endarterectomy (CEA) by application of intraoperative neuromonitoring (IONM). A total of 68 CEA patients were enrolled in this study. A 3-step IONM procedure was designed to obtain vocal fold EMG data at V1 (just after identification of the vagus nerve [VN]), V2 (just before arteriotomy), and V3 (just before wound closure). We also performed IONM before/after hemostasis near the VN using bipolar forceps and before/after dissection of the VN. All patients underwent laryngoscopy to assess postoperative VFP. One patient showed loss of EMG signals between V2 and V3 and developed VFP that persisted for 11 months. The other 62 patients had no loss of EMG signals, but 2 patients had confirmed VFP for 1 month after CEA. There were no changes of EMG signal before and after VN dissection or hemostasis with bipolar forceps near the VN.