Identification of patients with a non-recurrent inferior laryngeal nerve by duplex ultrasound of the brachiocephalic artery.

A non-recurrent inferior laryngeal nerve (NRILN) is a rare anomaly that may increase the risk of injury during thyroid surgery. A NRILN results from an embryologic developmental abnormality of the aortic arches, demonstrated by the absence of the brachiocephalic artery and the presence of an aberrant subclavian artery (arteria lusoria). In our experience 100% of 104 patients with a NRILN were shown to have these abnormalities. We postulated that duplex scanning of the brachiocephalic artery could identify patients at risk of a NRILN. Twelve patients with an operative diagnosis of a right NRILN and associated vascular abnormalities underwent postoperative duplex scanning of the brachiocephalic artery. The examination was performed using a 7.5 or 3.5 MHz transducer. The average duration of assessment was 5 min. The absence of the brachiocephalic artery and the direct origin of the right common carotid artery from the arch of the aorta were demonstrated in each patient. Duplex scanning is a simple noninvasive method of identifying patients with the arterial abnormalities responsible for a NRILN. This may be used in the preoperative assessment of selected patients.