Improvement in phonation after reconstruction of the recurrent laryngeal nerve in patients with thyroid cancer invading the nerve

Background. We report vocal improvement after reconstruction of the recurrent laryngeal nerve (RLN) in patients with nerve resection, although vocal cord movement was not restored. These methods are not widely recognized. Methods. Direct anastomosis, free nerve grafting, or anastomosis to the ansa cervicalis or the vagus nerves with the RLN were performed in 7, 14, 65, and 2 patients with thyroid cancer invading the RLN, respectively. A total of 51 patients had vocal cord paralysis (VCP) pre-operatively. Maximum phonation time (MPT) and vital capacity (VC) were measured before and 1 year after reconstruction. A total of 34 normal subjects and 27 patients with VCP served as controls. Results. Patients with VCP had significantly shorter MPT values than normal subjects. At 1 year after operation, patients with reconstruction had values of MPT similar to those of normal subjects. Men had significantly longer MPT values than women, but the phonation efficiency index (PEI), defined as the MPT/VC ratio, did not differ by sex. The PEI was significantly less in VCP patients than in normal subjects. Patients with reconstruction achieved PEI values similar to those in normal subjects. Phonation efficiency index values at 1 year after operation was significantly greater than pre-operative PEI and was not affected by the presence or absence of VCP pre-operatively, age, reconstruction method, thickness of suture thread, or use of magnification during the operation. Conclusion. In patients with thyroid cancer requiring RLN resection, RLN reconstruction achieved recovery in phonatory function. (Surgery 2009;146:1056-62.)