Topographical features of the vagal nerve at the cervical level in an aging population evaluated by ultrasound

Abstract

Objective: The vagal nerve (VN) can be located either dorsal or ventral to the common carotid artery (CCA). We analyzed the correlation between patient age and the depth of the left VN, assessed if patient age is a reliable predictor of VN location, and determined if preoperative ultrasound provides useful information for implantation surgery of a VN stimulator in epilepsy patients. Methods: From our database of cervical ultrasonography, examinations of 443 patients (71.8 ± 10.6 years; 332 men and 121 women) were reviewed. The VN, CCA, and internal jugular vein (JV) were identified at the level of the thyroid cartilage. Patients were classified into deep and superficial types in accordance with the relative location of the VN to the line connecting the centers of the CCA and JV (Line C). The ages of the two groups and the correlation between patient age and distance of the VN from line C were analyzed. Results: The VN was detected in all 443 patients between the CCA and the JV. The depth of the VN ranged from 7 mm deeper to 6 mm superficial to line C. There were 389 (87.8%) deep and 54 (12.2%) superficial types. Conclusion: Our study encourages utilizing longitudinal and cross-individual ultrasound studies within and amongst individuals of different ages to allow understanding the variations of the vagal nerve in its neck portion. This has implications to many neurosurgical procedures. Keywords: Vagal nerve, Anatomy, Ultrasound, Vagal nerve stimulation, Aging