A CASE OF NON-RECURRENT LARYNGEAL NERVE

Abstract

A case of non-recurrent laryngeal nerve is presented. A 63-year-old woman was admitted to the hospital because of a thyroid cancer. At the operation, the left recurrent nerve was seen in the usual position. But the right recurrent nerve was not present in the right tracheoesophageal groove. The right non-recurrent laryngeal nerve was arising from the cervical trunk of the vagus, and passing transversely into the right side of trachea. A post operative angiogram showed an abnormal right subclavian artery which directly arised from the distal part of aortic arch. She had no trachyphonia, dyspnea nor dysphagia. The right recurrent laryngeal nerve is embryologically related to the fourth arch vessel which becomes the right subclavian artery. Rarely, when the fourth vessel disappears, this nerve is not arrested by this vessel and arises directly from the vagus. Consequently, the right subclavian artery arises from the distal aorta, just distal to the left subclavian artery, and crosses to the right behind the trachea and esophagus. So, it can be associated with dysphagia. This type of anomaly is rare, but surgeons should know the presence of the non-recurrent laryngeal nerve for thyroidectomy. It is also necessary to follow the occurrence of dyspnea and dysphagia.