A study of the Topographical Anatomy of the External laryngeal Branch of Superior Laryngeal Nerve in patients undergoing Thyroidectomy

INTRODUCTION: Thyroidectomy is a frequently performed surgery all over the world. One forgotten and usually ignored complication is voice change. This can either be due to recurrent laryngeal nerve injury or external laryngeal nerve injury. The pattern of voice change varies in each of these injuries. Identifying the nerves during the surgery and a comprehensive knowledge about the variants of the nerves can be beneficial to the surgeon. AIM AND OBJECTIVES: To find out the prevalence of various courses of external branch of superior laryngeal nerve in patients undergoing thyroidectomy. MATERIALS AND METHODS: 50 patients undergoing thyroidectomy in the Department of General Surgery from April 2016 to September 2016 were studied. The course of external laryngeal nerve was classified according to Kierner Classification. RESULTS: The total number of nerves analysed were 83. The mean length of nerve was 2.21 cm. The most common type of EBSLN was type 1 [46.98%]. The second most common type of EBSLN was type 2[25.3%]. The third most common type of nerve was the nerve could not be identified in 22.89% of cases. The fourth most common type of type 4 nerve [4.81%]. There was no type 4 nerve identified in this study. CONCLUSION: The description of various courses of external branch of superior laryngeal nerve and its routine identification can minimise risk of iatrogenic injury to the nerve during thyroidectomy.