目的    观察甲状腺手术中喉返神经的喉外分支，探讨保护喉外分支的临床意义。 方法    对2009年1月至2011年1月昆明医学院第一附属医院胃肠与甲状腺外科由同一组外科医师连续收治的1346例甲状腺手术病人进行术中喉外分支观察，并复习相关文献。 结果    符合标准的病人943例，共显露1701条喉返神经，其中左侧843条，右侧858条；同时显露双侧神经758例。528条喉返神经观察到喉外分支，喉外分支发生率31.0%（528/1701），左侧36.3%（306/843），右侧25.9%（222/858）；双侧均有28.8%（218/758）。2分支发生率82.4%（435/528），3分支发生率17.6%。左侧喉返神经分叉点至入喉处的中位距离7.5 mm，右侧喉返神经分叉点至入喉处的中位距离为8.0 mm。喉返神经分叉点位于甲状腺下动脉神经交叉点上方452例，占85.6%（452/528）。医源性喉返神经损伤8例，2例永久损伤，暂时性神经损伤6例。 结论    喉返神经的喉外分支发生率和分支位置存在一定差异，喉返神经前支是支配声带的运动纤维。认识喉返神经的分支解剖特点，术中仔细辨认和保护喉返神经的每一个喉外分支对避免术后声带麻痹有重要意义。

Intraoperative investigation and the significance of extralaryngeal division of recurrent laryngeal nerve                       QIAN Jun，SU Yan-jun，ZHANG Jian-ming，et al. Department of Thyroid Surgery, First Affiliated Hospital of Kunming Medical University, Kunming 650032, China
Corresponding author：CHENG Ruo-chuan, E-mail：cruochuan@yahoo.com.cn
Abstract    Objective    To analyze the frequency of extralaryngeal branching（ELB）of the recurrent laryngeal nerve (RLN) in thyroidectomy and discuss the clinical significance of preserving extralaryngeal branching of RLN. Methods Intraoperative study the ELB of RLN in 1346 patients performed thyroidectomy by the same group of surgeons from January 2009 to January 2011 in the First Affiliated Hospital of Kunming Medical University was performed combined with pertinent literatures reviewed. Results    There were 943 patients enrolled in the research. Among them, 1701 RLNs were exposed and indentified (843 in left and 858 in right) and bilateral RLNs were exposed in 758 patients simultaneously. A total of 528 RLNs (31.0%) had extralaryngeal branches (306 in left and 222 RLNs in right), while 218 cases were bilaterally. Bifurcation occurred in 82.4% of the patients, while the other 17.6% were trifurcations. The median distance from branching point to entering point was 7.5mm on the left and 8mm on the right. Branching point above the inferior thyroid artery occurred in 85.6% nerves. There were 8 patients with nerves iatrogenic injured. Among them, 2 patients were temporary and 6 were permanent. Conclusion    The incidence of extralaryngeal branching of RLN and location of branching may be varied. However, the motor fiber of RLN is located in the anterior branch which controls the movement of vocal cord. Recognition of the frequent anatomical variation and meticulous preservation of all branches are of great importance to decrease postoperative vocal cord paralysis.