Carotid Endarterectomy for a Patient with a Right-sided Aortic Arch and Aberrant Left Subclavian Artery Predicting a Left Non-recurrent Inferior Laryngeal Nerve: A Case Report and Literature Review.

Cardiovascular malformations during embryogenesis can lead the inferior laryngeal nerve to branching directly from the cervical vagus nerve and entering the larynx. This rare anatomical variation is known as a non-recurrent inferior laryngeal nerve (NRILN), and increases the risk of accidental injury resulting in postoperative vocal cord paralysis during neck surgery. We report a case of an 83-year-old man who presented with left symptomatic internal carotid artery stenosis with a right-sided aortic arch and aberrant left subclavian artery (ALSCA). We performed carotid endarterectomy (CEA) using intraoperative neuromonitoring to avoid NRILN injury. To the best of our knowledge, this is the first report of searching for a left NRILN by electrophysiology during CEA. Neurovascular surgeons need to understand the variations of the NRILN associated with congenital cardiovascular anomalies and effective use of intraoperative nerve monitoring (IONM). We discuss the embryological origin, IONM, and surgical pitfalls of this case.