The inferior laryngeal nerve: surgical and anatomic considerations. Report of 251 thyroidectomies.

This surgical anatomic study aimed to determine (1) the anatomic relation of the laryngeal inferior nerve with the inferior thyroid artery, (2) the existence of extralaryngeal branches of division of the nerve and (3) the size of the nerve seen macroscopically. Two hundred and fifty-one patients underwent thyroid surgery during a period of 30 months. There were 50 males and 201 females. The male population underwent 28 total thyroidectomies, 13 left lobectomies and 9 right lobectomies. The female population underwent 124 total thyroidectomies, 33 left lobectomies and 44 right lobectomies. On the right side: the nerve was found superficial to the artery in 70.24% of females and 51.35% of males, the nerve was divided in 23.81% of females and 21.62% of males and seemed unusually thin in 14.29% of females and 5.41% of males. On the left side: the nerve was found superficial to the artery in 87.26% of females and 95.12% of males, the nerve was divided in 15.29% of females and 14.63% of males and seemed unusually thin in 10.83% of females and 2.44% of males. In conclusion, the inferior laryngeal nerve is characterized by its important anatomic variations, especially on the right side. These variations might be different even between males and females. Knowledge of these variations is very important in order to best identify and preserve the inferior laryngeal nerve during thyroid surgery.