Surgical anatomy of the recurrent laryngeal nerve; a cross-sectional descriptive study

Abstract

Objective: To describe the relationship of the recurrent laryngeal nerve (RLN) to the inferior thyroid artery and the ligament of Berry and to study its trajectory Method: Twenty patients who underwent total thyroidectomy and six who underwent thyroid lobectomy were included. 46 RLNs including 24 right and 22 left, were studied. The relationship of the nerve to the inferior thyroid artery, ligament of Berry and its course between these two structures were recorded after the surgery. Data were tabulated and analyzed using spread sheet application. Results: In 28 instances (61%; 80% of left and 50% of right), the nerve was posterior to the inferior thyroid artery while in 11 occasions (24%; 33% of right and 15% of left) the nerve travelled through the branches of the inferior thyroid artery. In four instances, (9%) the nerve was anterior to the inferior thyroid artery. In one instance, a single right non-recurrent laryngeal nerve (2%) was detected. The left inferior thyroid artery was absent in two patients. In 25 instances (54%), the nerve was in contact with the Berry's ligament while in 17 (37%) occasions the nerve travelled in between the ligament and tracheo-oesophagial groove (TOgroove) and in 3 instances (7%), the nerve travelled through the ligament. The observed right non-recurrent nerve (2%) was superior to the ligament. The trajectory of the RLN from the inferior thyroid artery level to the ligament of Berry fell into eight categories. In 70% instances, RLN (77% of left and 63% of right) was in the tracheo-oesophageal groove at the inferior thyroid artery level. Conclusion: RLN is usually posterior to the inferior thyroid artery. Relationship between right RLN and the inferior thyroid artery is more variable than that between the left RLN and inferior thyroid artery. RLN is commonly in contact with the ligament of Berry. Most of the time (79%) the left RLN was found to be in the TO groove, deep to the inferior thyroid artery while the right RLN showed a more variable position. The trajectory of the nerve from the inferior thyroid artery level to the level of ligament of Berry was highly variable. Occasionally, the presence of the right non recurrent laryngeal nerve should be expected. Key words: Recurrent laryngeal nerve; inferior thyroid artery; ligament of Berry. DOI: 10.4038/gmj.v15i1.2390 Galle Medical Journal Vol.15(1) 2010 pp.14-16