====== Vagus nerve monitoring ======
Surgery for tumors around the [[jugular foramen]] has significant risks of [[dysphagia]] and [[vocal cord palsy]] due to possible damage to the lower [[cranial nerve]] functions. For its treatment, long-term tumor control by maximum [[resection]] while avoiding permanent neurological damage is required. To accomplish this challenging goal, Matsushima et al. developed an intraoperative continuous [[vagus nerve]] monitoring system and herein report their experience with this novel [[neuromonitoring]] method.

Fifty consecutive patients with tumors around the jugular foramen (34 [[jugular foramen schwannoma]]s, 11 [[meningioma]]s, 3 [[hypoglossal schwannoma]]s, and 2 others) who underwent microsurgical resection under continuous vagus nerve [[monitoring]] within an 11-year period were retrospectively investigated. Evoked vagus nerve electromyograms were continuously monitored by direct 1-Hz stimulation to the nerve throughout the microsurgical procedure.

The average resection rate was 96.2%, and no additional surgery was required in any of the patients during the follow-up period (average 65.0 months). Extubation immediately after surgery and oral feeding within 10 days postoperatively were each achieved in 49 patients (98.0%). In 7 patients (14.0%), dysphagia and/or hoarseness were mildly worsened postoperatively at the latest follow-up, but tracheostomy or gastrostomy was not required in any of them. Amplitude preservation ratios on intraoperative vagus nerve electromyograms were significantly smaller in patients with postoperative worsening of dysphagia and/or hoarseness (cutoff value 63%, sensitivity 86%, specificity 79%).

Intraoperative continuous vagus nerve monitoring enables real-time and quantitative assessment of vagus nerve function and is important for avoiding permanent [[vagus nerve palsy]] while helping to achieve sufficient resection of tumors around the jugular foramen
((Matsushima K, Kohno M, Ichimasu N, Tanaka Y, Nakajima N, Yoshino M. Intraoperative continuous [[vagus nerve monitoring]] with repetitive direct stimulation in surgery for [[jugular foramen tumor]]s. J Neurosurg. 2021 Feb 19:1-8. doi: 10.3171/2020.8.JNS202680. Epub ahead of print. PMID: 33607614.)).