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

Abstract

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.

Surgical anatomy of the external branch of the superior laryngeal nerve and its clinical significance in head and neck surgery

“…The variability in the anatomical course of the EBSLN often makes the intra-operative identification of the nerve challenging, and despite meticulous dissection the nerve may still be injured (Moosman and DeWeese, 1968;Lekacos et al, 1987;Lore et al, 1998;Dackiw et al, 2002;Page et al, 2004). The key in identifying the EBSLN is to develop the avascular plane between the medial border of the upper pole of the thyroid gland and the cricothyroid muscle (space of Reeve or cricothyroid space) (Aina and Hisham, 2001;Younes and Badran, 2002).…”

Atypical anastomosis of laryngeal nerves

“…4a and 4b), lateral to the insertion of the inferior constrictor muscle (Page et al, 2004), innervating this muscle as it pierces it. It then terminates on the cricothyroid muscle, making this muscle the only intrinsic muscle of the larynx that does not derive its motor innervation from the recurrent laryngeal nerve (Williams et al, 1989).…”

Identification and preservation of External Branch of the Superior Laryngeal Nerve during thyroid surgeries at NMCTH

“…14 25 have reported lack of any added benefit of nerve stimulator in identifying type II nerves which were low lying and vulnerable. Page 26 in a study of 50 thyroidectomies also felt systemic search for EBSLN is not useful. In our study, we relied on visual identification alone due to lack of equipment.…”