Right Non-recurrent Inferior Laryngeal Nerve Discovered During Carotid Endarterectomy: A Case Report and Literature Review

The recurrent inferior laryngeal nerve (RILN) origins from the vagus trunk and, recurring into the mediastinum, courses then into the larynx. Sometimes this nerve can assume an unusual pathway, coursing directly into the larynx. This anomaly is the so-called non-recurrent inferior laryngeal nerve (NRILN) and represents a rare entity, with an incidence between 0.3% and 1.6%. It is commonly caused by an embryologic anomaly of the aortic branches and, for this reason, it occurs most on the right and is closely associated with an aberrant subclavian artery (also named arteria lusoria). The peculiar anatomy of this nerve must be well-known by surgeons, in order to prevent accidental injuries and avoid post-operative complications, such as vocal cords paralysis. There are other anomalies of cervical nerves (i.e. sympathetic-inferior laryngeal nerve anastomotic branches, SILAB) that simulate the NRILN and it is of paramount importance for the surgeon to distinguish them. In this article, we present the case of a patient undergoing a carotid endarterectomy (CEA), in which a right NRILN was found intraoperatively. We found that this NRILN was associated with no right aberrant subclavian artery, but with an anomalous origin of the brachio-cephalic trunk. Key points in differential diagnosis, embryological origin and surgical implications are discussed.