Although the presence of a non-recurrent inferior laryngeal nerve (NRILN) is rare, surgeons occasionally encounter this anomaly during thyroid and parathyroid surgery. It is usually due to anomalous nerve and blood vessel development from the embryonic branchial arches.
We recently encountered two patients with NRILN. One represented type 1 branching from the vagus trunk at the level of the inferior thyroid artery, and the other, type 2 branching at the level of the superior pole of the thyroid gland.
Avoiding injury to the inferior laryngeal nerve is a major consideration during thyroid and parathyroid surgery. Because in most cases, including our two cases, NRILNs are associated with anomalous origin of the right subclavian artery from the aortic arch, this anomaly can be predicted by imaging procedures. Therefore, surgeons must pay careful attention to the preoperative examination findings in order to reduce the risk of injury of this nerve.