一种喉返神经入喉处的变异探讨

A variation of the recurrent laryngeal nerve at its entry to larynx found in the thyroid surgery

目的 分析报告一种喉返神经入喉处的变异.方法 1998年1月至2008年12月共有3078例患者行显露喉返神经的甲状腺手术,其中男性683例,女性2395例.为了避免误伤喉返神经,共显露了4241根甲状腺段的喉返神经.总结报告其中一种变异喉返神经的变异情况.结果 发现入喉处变异的喉返神经44根（1.0%,44/4241）,其变异情况是喉返神经主干或其分支在远离环甲关节后方处人喉,入喉处距环甲关节后方的距离超过5 mm.根据术中发现可将上述入喉处变异的神经分为4种类型：Ⅰ型,变异的喉返神经无分支,主干直接走行至远离环甲关节后方的环甲肌下方入喉,该型共35根（79.6%,35/44） Ⅱ型,变异神经先发出2根分支,1根分支仍走行至环甲关节附近入喉,另1根分支走行至远离环甲关节后方的环甲肌下方入喉,该型有5根（11.4%,5/44） Ⅲ型,变异神经先发出2根分支,2根分支共同走行至远离环甲关节后方的环甲肌下方入喉,该型共3根（6.8%,3/44） Ⅳ型,变异神经先发出3根分支,其中最外侧1根分支走行至远离环甲关节后方的环甲肌下方入喉,该型共1根（2.2%,1/44）.术中误伤变异神经4根（9.1%,4/44）.结论 对外科医生来说,有必要了解尽可能多的喉返神经变异情况,以期尽可能地降低喉返神经误伤的发生率.

Objective To describe a new variation of the recurrent laryngeal nerve （RLN） at its entry to larynx. Methods A 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. Results Forty-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 cothyroid joints. The distance from the entry to the back of cothyroid joints was over 5 mm. Among these, eight RLNs （23. 5%, 8/34） walked distally from the dorsal cricothyroid joint without extralaryngeal 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 variated RLNs were injured during the operation （9. 1%, 4/44）. Conclusion The variation of RLN reported in this study is more dangerous and should be paid more attention to lower the injury of the nerve.