Two Concomitant Right Nonrecurrent Laryngeal Nerves Encountered During Thyroidectomy (Type 4 Course): Reported for the First Time

Abstract

Introduction: The recurrent laryngeal nerve gains its name because after branching from the vagus nerve, it turns superiorly (recur) around the subclavian artery on the right and around the ligamentum arteriosum on the left, the nonrecurrent nerve has a straight direct course to the larynx and doesn’t follow this course. It presents mostly on the right side. The presence of this variation places the nerve at higher risk of injury during neck surgery especially thyroid operations. Case Presentation: A 45-year-old lady presented with painless thyroid enlargement for 1 year. Thyroid examination showed a 3-cm firm nodule at the right thyroid lobe with normal thyroid function tests. Right thyroid lobectomy was done and the histopathology showed a benign follicular lesion. During surgery, we discovered 2 nonrecurrent laryngeal nerves at the right side which were arising from the vagus nerve and both were entering the larynx. Conclusion: Failure in identification of the nerve or overlooking the possibility of the non-recurrent laryngeal nerve may result in a serious sequelae of nerve damage, ipsilateral injury may lead to permanent hoarseness and bilateral injury may result in severe dyspnea or aphonia. Currently, there are 3 types of nonrecurrent laryngeal nerve courses. Type 1 passes near to the superior thyroid vessels. Type 2 (2A) passes parallel to the inferior thyroid artery and has a transverse course above it. Type 3 (2B) passes parallel to the inferior thyroid artery and transversely between branches of or under the inferior thyroid artery, we can add to this classification type 4, which are 2 nonrecurrent laryngeal nerves (double nerves) passing above and parallel to the inferior thyroid artery.