Possibilities of preoperative ultrasound of neck vessels in the diagnosis of non-recurrent laryngeal nerve

Abstract

Background: According to the anatomical data, the non-recurrent laryngeal nerve is a rather common abnormality and can be found in 4.78% of people. At the same time, the non-recurrent laryngeal nerve is difficult to visualize during surgery, which increases the risk of its damage.
 Aim: to determine the possibilities of ultrasound of neck vessels in the preoperative diagnosis of the aberrant right subclavian artery (arteria lusoria) and the abnormality of the branches of the vagus nerve.
 Materials and methods: An observational, single-center, single-stage, randomized, uncontrolled clinical trial was performed, which included patients in whom surgery was performed due to thyroid and parathyroid pathology. In the preoperative period, all patients underwent the ultrasound of the right half of the neck vessels and the mediastinum with visualization of the brachiocephalic trunk and its branches. When the brachiocephalic trunk was detected in the preoperative period, mobilization of the thyroid gland during operation was started with ligation of the upper pole vessels, and followed by a search for the recurrent laryngeal nerve. However, if the brachiocephalic trunk was absent, the right common carotid artery was traced as low as possible to the aortic arch and assessed on its relationship with the right subclavian artery. In such cases, thyroid mobilization was started from the lateral surface of the lobe with the necessary visualization of all structures of this region and followed by a primary search for the inferior laryngeal nerve. When the non-recurrent laryngeal nerve was detected, the computed tomography of the brachiocephalic arteries was performed in the postoperative period.
 Results: The study has shown that 202 (95.28%) patients out of the total 212 revealed the brachiocephalic trunk on preoperative ultrasound and the recurrent laryngeal nerve was located in a the typical place. Arteria lusoria was detected in 4 (1.89%) cases after the preoperative ultrasound. In this group of patients the non-recurrent laryngeal nerve was identified during operation and the aberrant right subclavian artery was confirmed at computed tomography. In 6 (2.83%) cases the brachiocephalic trunk could not be detected on ultrasound due to the constitutional features of the patient. However, in all these cases, the typical recurrent laryngeal nerve was identified during a surgery.
 Conclusions: The ultrasound of the neck vessels is the effective method to detect arteria lusoria, which is the predictor of the non-recurrent laryngeal nerve.