Nonrecurrent and recurrent inferior laryngeal nerve: A surgical pitfall in cervical exploration

Abstract

The exposure and preservation of the recurrent inferior laryngeal nerve is advocated by most experienced thyroid surgeons as the standard of care and as an essential component of routine dissection in cervical exploration. Anatomic variations in the position of this vital structure may present pitfalls during thyroidectomy. The nonrecurrent inferior laryngeal nerve: The possibility of a nonrecurrent inferior laryngeal nerve is a known but rare (0.6%) anatomic variant. A nonrecurrent nerve may come directly from the vagus nerve high in the neck and run in a straight course toward the cricothyroid membrane in contrast to the normal retrograde entry into the larynx from the thoracic vagus. This abnormality was first described in autopsy cases [I], and, later, encountered in a surgical case report [ 21 and in a short series [ 31. An explanation has been sought for this abnormal course of the inferior laryngeal nerve by its association with embryologic vascular abnormality. In the embryologic origin of the aortic arches, an atypical development may result in an aberrant right subclavian nerve with the origin of the aorta left of the midline following a retroesophageal course. Nonrecurrence of the inferior laryngeal nerve on the left side: The embryologic explanation is most compatible with the nonrecurrent inferior laryngeal nerve described on the right side. There are very rare excep tions, reported in an autopsy case [4] and in two clinical cases [5], of a left-sided nonrecurrent inferior laryngeal nerve associated with a right-sided aorta and a left retroesophageal subclavian artery. The complex of these anatomic abnormalities was confirmed in two similar cases [Jl. Ipsilateral recurrent and nonrecurrent nerve: