Non recurrent laryngeal nerve: be vigilant

The nonrecurrent laryngeal nerve (NRLN) is a rare variant of the RLN, which results from the partial failure of pharyngeal apparatus during embryological development. It’s a rare anatomical variation in which the nerve doesn’t descend to the thorax and enters the larynx directly from the vagus nerve in the neck. It’s an uncommon anatomical variation usually associated with subclavian artery abnormalities, so identification of these vascular anomalies before the surgery is important to avoid nerve injury. These anomalies lead to difficulty in finding the RLN and hence the chances of injury to the nerve are more. Lack of knowledge about the course of RLN, its anatomical variations and its relationship to the vital structures poses the risk of iatrogenic damage of the nerve. Most of the cases of NRLN are diagnosed intraoperatively, as there is no specific test for this. So, surgeons should always be vigilant about the NRLN during thyroid and parathyroid surgeries.