Preservation of recurrent laryngeal nerve invaded by differentiated thyroid cancer

This study was undertaken to determine whether the recurrent laryngeal nerve involved in differentiated thyroid carcinoma could be preserved.

Few investigations have provided definitive results concerning preservation of the recurrent laryngeal nerve involved in thyroid cancer. Complete excision with resection of the recurrent laryngeal nerve reportedly did not improve survival over incomplete excision in differentiated thyroid carcinoma.

A retrospective study was performed with the medical records of 50 patients with differentiated carcinoma and preoperative normal vocal cord function to investigate outcomes of recurrent laryngeal nerve preservation including local recurrence, prognosis, and postoperative vocal cord function. The recurrent laryngeal nerves on 1 or both sides were preserved in 23 patients (the preserved group), whereas the involved recurrent laryngeal nerve of the other 27 patients was resected (the resected group).

Backgrounds of patients were similar between the resected and preserved groups. The number of patients with recurrences in each group was similar, and incidence of local, regional, and distant metastatic recurrences were not different between the groups. Postoperative overall survival of the preserved group was similar to that of the resected group (p = 0.1208). More than 60% of patients or of nerve at risk in the preserved group restored normal vocal cord function within 6 months. Some functional vocal cord movement was recognized in 80% of patients or of nerve at risk. All patients in the resected group including patients with nerve anastomosis showed permanent paralysis of the ipsilateral vocal cord.

These results suggested that the recurrent laryngeal nerve, even if infiltrated by differentiated thyroid cancer, is worthwhile to preserve for maintenance of postoperative vocal cord function without affecting the incidence of local recurrence or prognosis.