Thyroid and parathyroid surgery are generally associated with a low risk of recurrent laryngeal nerve (RLN) injury, especially with the increased use of intraoperative neuromonitoring. However the presence of a non-expected non-recurrent laryngeal nerve (NRLN), a rare anatomical variation in which the nerve enters the larynx directly off the cervical vagus nerve, increases this risk. The NRLN may be associated with vascular abnormalities, such as the presence of an aberrant right subclavian artery.  Preoperative ultrasonography (US) is a cheap and widely available diagnostic tool to detect the arterial abnormalities associated with NRLN.

We reviewed our database of patients who underwent thyroid and parathyroid US performed by a surgeon, between March 2014 and november 2023.

In 19 of a total of 2616 cases, the brachiocephalic trunk was not visualized on US. Three patients had a normal, but mediastinal brachiocephalic trunk, not accessible with US, but detected in the CT scan. In 3 cases a NRLN was detected during surgery. The neck US performed posteriorly didn't show the presence of a brachiocephalic trunk, which was confirmed on CT scan. The 9 operated patients - 5 type 2A, 2 type 1 and 1 type 2B NRLN (in 1, the right side was not approached) - had no complications.

Thus, we emphasize the importance of the diagnosis of NRLN in the preoperative US to avoid iatrogenic lesions with known impact in the quality of life of patients, and we propose the use of US performed by a surgeon as a first approach