OBJECTIVETo describe a new variation of the recurrent laryngeal nerve (RLN) at its entry to larynx.

METHODSA retrospective study including 3 078 consecutive cases received thyroidectomy was performed from January 1998 to December 2008. The age ranged from 15 to 82 years, 2 395 cases were female and 683 cases were male. A total of 4 241 RLNs were exposed successfully for avoiding the injury of the nerve. A kind of variation of the RLN was reported in this study.

RESULTSForty-four varied RLNs were identified at the entry into the larynx (1.0%, 44/4241). Variation happened at the truck or the branches of RLN entering the larynx far from the posterior cricothyroid joints. The distance from the entry to the back of cricothyroid joints was over 5 mm. Among these, eight RLNs (23.5%, 8/34) walked distally from the dorsal cricothyroid joint without extra laryngeal branches and entered the larynx at the abnormal point. There were four different kinds of sub-variations identified: type I: there was no branch in RLN and the varied RLN entered the larynx far from the posterior cricothyroid joints, total 35 cases (79.6%, 35/44); type II: there were two branches in RLN, one branch entered the larynx at the posterior cricothyroid joints and the other far from the posterior cricothyroid joints, total 5 cases (11.4%, 5/44); type III: there were two branches in RLN, and both branches entered the larynx far from the posterior cricothyroid joints, total 3 cases (6.8%, 3/44); type IV: there were three branches in RLN, the lateral branch of the varied RLN entered the larynx far from the posterior cricothyroid joints, total 1 case (2.2%, 1/44). Four varied RLNs were injured during the operation (9.1%, 4/44).

CONCLUSIONThe variation of RLN reported in this study is more dangerous and should be paid more attention to lower the injury of the nerve.