Non-Recurrent Right Laryngeal Nerve: a Rare Anatomic Variation Encountered During a Total Thyroidectomy.

The non-recurrent laryngeal nerve (nRLN) is a rare anatomic variation that every head and neck surgeon must be aware of, in order to avoid intraoperative injury which leads to postoperative morbidity. We are reporting a case of a nRLN in a 47 year old female patient with medullary thyroid carcinoma who was surgically treated with total thyroidectomy and lymph node dissection. Both two inferior laryngeal nerves were identified, fully exposed and preserved along their cervical courses. However, we found that the right inferior laryngeal nerve was non-recurrent and directly arised from the cervical vagal trunk, entered the larynx after a short transverse course and parallel to the inferior thyroid artery. The safety of thyroid operations is dependent on high index of suspicion, meticulous identification and dissection of laryngeal nerves either recurrent or non-recurrent. This leads to minimum risk of iatrogenic damage of the nerves. Complete knowledge of the anatomy of these neural structures, including all their anatomic variations is of paramount importance.