Non-Recurrent Laryngeal Nerve (NRLN): A rare anatomical anomaly of the recurrent laryngeal nerve

Abstract

A 34-year young lady with a right-sided euthyroid nodule of 3x5 cm size for one year visited our clinic for surgery. FNAC was reported as colloid goiter. The right hemi-thyroidectomy surgery was planned. Intraoperatively while dissecting the right thyroid lobe, we could not find the right recurrent laryngeal nerve in its normal course, but we found a cord white-like structure running transversely & entering the larynx at the level of the cricothyroid muscle. We dissected it till its origin from the right vagus nerve in the neck. So, this was Non-recurrent laryngeal nerve (NRLN) which is a rare anatomical anomaly of the Recurrent Laryngeal Nerve (RLN) which arises higher in the neck and runs a course directly to the larynx as the NRLN without looping around the vessels in the chest. This intraoperative image is showing right-sided neck structures after removal of the right thyroid lobe & isthmus. The labeled structures in the image from right to left are the common carotid artery (CCA), Vagus Nerve (VN), Non-recurrent laryngeal nerve (NRLN), trachea & left lobe of the thyroid gland. Her post-operative recovery was good without any voice change. The final histopathology report was suggestive of colloid goitre.