A loop-forming duplicate recurrent laryngeal nerve: report of a case and clinical relevance in thyroid surgery.

This is a report of a unilateral loop-forming duplicate recurrent laryngeal nerve and its clinical relevance. A 72-year-old woman with a giant goiter underwent a total thyroidectomy. At operation we identified two recurrent laryngeal nerves on the right side and one on the left side. The nerve on the right was smaller and displaced laterally by the goiter, whereas the other was adjacent to the trachea and behind the goiter, and it was accidentally divided. Both nerves were united before innervating the larynx. The divided nerve was microsurgically reanastomosed but a postoperative assessment revealed hoarseness. This case report of an anomalous loop-forming duplicate recurrent laryngeal nerve indicates that it may not be sufficient to identify a single recurrent laryngeal nerve on one side during thyroid surgery especially when the observed recurrent nerve is relatively smaller than usual.