目的 研究甲状腺癌导致喉返神经(recurrent laryngeal nerve，RLN)条件变异的病理学特点，探讨甲状腺癌术中神经监测(intraoperative neuromonitoring，IONM)对RLN条件变异的识别、辨认及保护。方法 回顾性分析2012-03至2014-03在本院因甲状腺癌行甲状腺全切术并行IONM患者资料，依据肿瘤生物学特性，对RLN 条件变异进行病理学分类，为IONM 准确识别及有效保护RLN 提供病理学支持。结果 240例术中显露RLN共436支，其中发现条件变异48支(10.76％)。RLN条件变异与甲状腺癌生物学特性相关，依据病理类型将条件变异分为:位置变异型、形态变异型、病变浸润型。应用组分别检出:12、9、15支;非应用组分别检出:3、4、5支。2组RLN 条件变异识别率，分别为:36/215， 12/231，2组比较有统计学意义(P＜0.05)。结论 RLN 条件变异是导致术中对RLN错误识别，以及造成RLN 损伤的重要潜在因素，IONM有利于术中确认RLN各种变异的病理解剖特点，以有效保护RLN。

Objective To analyze the pathological characteristics that thyroid carcinoma leads to recurrent laryngeal nerve injury and detect effectiveness of intraoperative nerve monitoring, recognize,identify and protect recurrent laryngeal nerve. Methods Clinical data of patients with thyroid cancer undergoing total thyroidectomy with intraoperative nerve monitoring were analyzed retrospectively from March 2012 to March 2014 in this hospital.A classification of variation of recurrent laryngeal nerve was made, based on biological characteristics of tumor,as a biological support for recognizing recurrent laryngeal nerve exactly,protecting recurrent laryngeal nerve effectively. Results 436 nerves were exposed in 240 operations,in which 48 variations (10.76％)were found. Variation was related to biological characteristics of thyroid cancer.The variations were classified into location variation type,form variation type, infiltrative lesions variation type.12,9 and 15 cases were identified in studymental group;3,4 and 5 cases were identified in control group.The rates of identification in both two groups were 36/215 and 12/231, showed significant differences(P＜0.05). Conlusions Variation of recurrent laryngeal nerve is vital and potential factor leading to misrecognizition of recurrent laryngeal nerve and recurrent laryngeal nerve injury.