A rapid and accurate technique for the identification of the recurrent laryngeal nerve

We studied the anatomic relationship between the recurrent laryngeal nerve (RLN) and the third tracheal ring, which was very important for rapid identification of RLN in our hands.

This study was initially performed using 8 fresh cadavers (4 female and 4 male). The transverse nerve location from the third trachea and the depth from its anterior surface were measured. We further observed the topography of RLN in relation to the trachea in 60 patients, between November 2008 and January 2011, at the Tri-Service General Hospital and Buddhist Tzu Chi General Hospital, Taipei Branch, Taiwan, with 46 lobo-isthmectomies and 14 total thyroidectomies. The time spent in identifying the RLN was also recorded.

Among cadaver groups, the transverse distance (width) and the vertical distance (depth) averaged 3.3 and 17.6 mm, respectively. Among the clinical cases, the width and depth averaged 4.4 and 14.6 mm, respectively. The depth measured in males was significantly deeper than that in females (22.3 vs 13.2 mm) (P < .05). The time spent in identifying the RLN after starting dissection in the RLN triangle was not statistically significantly different between the cadaver group and the clinical group (10.6 ± 5.7 seconds and 15.5 ± 17.7 seconds, respectively; P > .05). The median time was 9 and 10 seconds, respectively. There was no statistically significant side-to-side difference in terms of the time spent in searching for the RLN.

Using the third ring as guidance, our inferior-superior technique offers an extra benefit in identifying the RLN safely and quickly, as compared to the conventional inferior approach.