Knowledge of anatomical relationships of the vagus nerve with internal jugular vein and common carotid artery in the neck necessary for vagus nerve stimulation(VNS) surgery

Abstract

A precise understanding of the anatomy is essential to perform vagus nerve stimulation(VNS) therapy for refractory epilepsy. We evaluated the anatomical relationships of the cervical vagus nerve with the carotid artery and jugular vein on the basis of findings during VNS surgery. We investigated the anatomical relationships among the vagus nerve(VN), common carotid artery(CCA), and internal jugular vein(IJV) in 73 patients who underwent VNS surgery at our hospital from December 2010 to January 2015, classified the position of the VN into 5 categories, and studied the frequency of each category. The position of the VN was medial to the IJV and ventral to the CCA(type 1)in 8 patients(10.9%), medial to the IJV and lateral to the CCA(type 2) in 4(5.5%), dorsomedial to the IJV and ventral to the CCA(type 3) in 51(70%), dorsomedial to the IJV and lateral to the CCA(type 4) in 7(9.5%), and dorsal to the CCA(type 5) in 3(4.1%). This report is the first to propose a classification of the anatomical relationships of the VN with the CCA and IJV based on intraoperative findings. According to this classification, the difficulty of VNS surgery increases with advances of the type. Type 3 was the most frequent, and types 2 and 5 were rare. Understanding the variation in the position of the cervical vagus nerve is considered to contribute to safer surgical manipulations in VNS surgery.