The recurrent laryngeal nerve related to thyroid surgery

Iatrogenic injury of inferior laryngeal nerve is one of the most serious concerns in thyroid surgery. Paralysis of vocal cords is a common sequela of thyroidectomy. It represents a serious complication inducing, when bilateral, serious functional sequelae such as phonatory, respiratory and psychological problems that limit working capacities and social relationships of patients. We carried out an intraoperative study aimed to define anatomical relationships between the recurrent laryngeal nerve and the adjacent structures (the inferior thyroid artery in particular), intraoperative identification of which may allow prevention of iatrogenic injuries of the laryngeal nerve.

One hundred ninety-two patients (165 females, 27 males whose age was between 18 and 90 years, median age 55) who had undergone thyroidectomy in our department in the last 3 years. Among them, 179 patients underwent total extracapsular thyroidectomy, and of the 13 remaining, 12 were completions of thyroidectomy in patients who had previously undergone a first thyroid surgical intervention and underwent istmo-lobectomy.

Despite a systematic intraoperative search, we identified the recurrent laryngeal nerve in 158 of 192 patients (82.3%), while in the remaining 34 (17.7%), the recurrent laryngeal nerve was not identified. In 122 out of the 158 patients (77.2%) in whom the recurrent laryngeal nerve had been detected, the nerve was identified bilaterally: in 19 of 158 (12%) only on the right side; in 17 of 158 (10.7%) only on the left. Concerning the postoperative results we noticed only one case (0.5%) of recurrent laryngeal nerve injury for neoplastic infiltration of its own branch, one case (0.5%) of monolateral cordal hypomotility, and two cases (1.04%) of bilateral cordal hypomotility with temporary disphonia, which regressed in 6 months of time.

The results of our study may confirm that iatrogenic injury to the recurrent laryngeal nerve, or to its branches, might be better avoided by searching, identifying, and exposing the nerve itself and by following its course with care. In our view, total extracapsular thyroidectomy, with systematic search for the nerve, is the best approach. We believe that deep knowledge of the thyroid region's surgical anatomy and the awareness of the extremely varying course of the recurrent laryngeal nerve and the inferior thyroid artery and their relations should be taken into account by surgeons.