Left Nonrecurrent Laryngeal Nerve: A Very Unusual Finding during Thyroid Surgery

Abstract

Background. Identifying the inferior laryngeal nerve is one of the main concerns in thyroid surgery. The typical recurrent position occurs due the relative position between the vagus nerve and the larynx during the last 3 branchial arches development. In rare cases, this nerve does not loop under the right subclavian artery or the aortic arch. This abnormality is present in 0.7% of patients and is associated with the presence of anatomical vascular anomalies. The left non-recurrent inferior laryngeal nerve is an even rarer abnormality, with only six cases described in the literature to date. Method. A 46- years old female patient referred to total thyroidectomy for symptomatic multinodular benign goiter. Results. A left non-recurrent inferior laryngeal nerve was found with difficulty and then a partial thyroidectomy was performed. CT scan showed dextroposition of the vessels of the base of the heart and an aberrant left subclavian artery. Conclusion. An association of a right-sided aortic arch and aberrant left subclavian artery, or the presence of situs inversus, although rare anatomical variations, are associated to a non-recurrent inferior left laryngeal nerve. Proper identifying these abnormalities may help to properly identify and salvage this structure.

Systematic Review and Meta-Analysis: Recurrent Laryngeal Nerve Variants and Their Implication in Surgery and Neck Pathologies, Using the Anatomical Quality Assurance (AQUA) Checklist

“…Furthermore, two studies reported that it is important to consider the possible variants of the RLN or the NLRN based on a timely physical and imaging examination, which could reduce iatrogenic damage such as injury to the ITA, structures that run through the tracheoesophageal groove, or by last structures associated with innervation of the RLN [ 11 , 58 ]. One study reported that clinical and preoperative evaluation is important because the presence of NRLN is associated in some cases with dysphagia and silhouette abnormalities visible on radiographs in the mediastinal region, thus avoiding surgical complications [ 59 ]. One study reported preoperative paralysis of the vocal cords due to the compression of a variant of the RLN route associated with a thyroid tumor [ 60 ].…”

Non-recurrent laryngeal nerve in thyroid and parathyroid surgery

“…При этом, по данным метаанализа, такой тип нерва среди всех выявленных НВГН отмечен в 2,9% случаев [16]. Кроме того, авторами описано 4 левосторонних варианта нерва без транспозиции органов в сочетании с правой дугой аорты и левой аберрантной подключичной артерией [17][18][19][20].…”