Non-recurrent inferior laryngeal nerves and sympathetic-inferior laryngeal anastomotic branches: 6 years' personal experience

The incidence and possible association of inferior laryngeal nerve and sympathetic anastomotic branch anomalies were evaluated in this study. Non-recurrent inferior laryngeal nerves stem from vascular anomalies involving the right subclavian artery and aortic arches during embryological development. These anomalies usually have no functional consequences (except for occasional dysphagia), but are potentially dangerous during thyroid surgery, occurring in about 1% of cases. Sympathetic-inferior laryngeal anastomotic branches are described in about 1.5% of cases, and may be confused with non-recurrent inferior laryngeal nerves. 1473 patients submitted to total thyroidectomy for benign disease over the period 2001-2006 were evaluated. Four non-recurrent inferior laryngeal nerves (incidence: 0.27%) and 11 sympathetic-inferior laryingeal anastomotic branches (incidence: 0.74%) were observed. Out of a total of 25 definitive inferior laryngeal nerve lesions, 1 occurred in a case of non-recurrent inferior laryngeal nerve. Awareness of the anatomical anomalies described and accurate surgical technique, including a constant search for the inferior laryngeal nerve, are the requirements for identification of non-recurrent inferior laryngeal nerves and sympathetic-inferior laryngeal anastomotic branches. During the pre-operative workup, ultrasonographic study of the right subclavian artery may be advisable in order to rule out alterations of its origin and course.