Assessment of the Vagus Nerve Through Ultrasound-based Measurements and Associated Variables
Rachal Hegde1, Japnit Dham1, Hannah Shoctor1, Eugene Choe1, Neysa Sanghavi1, Ivonne Meares1, Bayann Rajamanar1, Henry Okodaso1, Haider Hilal1, Tarek Almabrouk1, James Coey1
1St. George's University
Objective:
This study aims to investigate ultrasound-based measurements of the vagus nerve through determining reference values of four cross-sectional area (CSA) landmarks, in addition to further assessing relationships between demographic variables and vagus nerve measurements.
Background:
Currently, there is limited ultrasonographic literature in regards to reference values of the vagus nerve in healthy populations.
Design/Methods:
This study encompassed 63 healthy participants (mean age = 22; 30 males, 33 females). A GE Cares InSite ultrasound system, equipped with a 12L-RS transducer linear probe, was utilized. The vagus nerve was visualized just prior to the bifurcation point of the common carotid artery and the internal jugular vein within the carotid sheath (proximal landmark) and at the inferior border of the thyroid gland (distal landmark). Bilateral measurements of both anterior-posterior and transverse diameters at these landmarks were collected in order to determine CSA values. Subsequent data analysis involved an ANOVA for group comparisons (male vs. female). Additionally, Spearman correlations were performed to investigate associations between CSAs and demographic variables (age, race).
Results:
Established CSAs of the vagus nerve are as follows: proximal left (2.54 ± 0.9 mm2), distal left (2.58 ± 1.2 mm2), proximal right (2.32 ± 0.8 mm2), and distal right (2.70 ± 1.0 mm2). No significant differences were observed between left and right landmarks. Males had significantly larger proximal (d= 0.77, p-value= 0.004) and distal (d= 0.93, p-value= 0.001) CSAs on the right side compared to females. No significant associations were observed between CSA landmarks and additional demographic variables (p > 0.05).
Conclusions:
Our analysis established standardized reference points for the vagus nerve at essential anatomical sites. Furthermore, vagus nerve CSA was significantly larger in males compared to females on the right side for both proximal and distal landmarks, highlighting gender-specific variations.