喉返神经损伤后喉肌病理生理研究

Characteristics of intrinsic laryngeal muscle after recurrent laryngeal nerve injury

目的:通过对犬喉返神经损伤及再生过程中喉肌电生理及其病理变化进行研究,探讨喉返神经不同损伤形式的病理生理改变及转归特点。方法:实验用犬20只(40侧)分为喉返神经完全损伤组(全切法)、不完全损伤组(结扎法、挫灭法、半切法)及对照组,造模成功后的即刻、1、3、6和12个月观察甲杓肌和环杓后肌肌电特征及组织病理学改变。结果:造模后即刻全切法及结扎法肌电为电静息,挫灭法和半切法存在部分正常单个运动单位(MUP)及振幅减小的MUP混合肌电。神经损伤后1～3个月可出现纤颤电位,不完全损伤组3～6个月出现再生电位。全切法诱发电位基本无法引出,结扎法和半切法早期无诱发电位,后期可以引出振幅减小的诱发电位,结扎法小于半切法;而挫灭法始终都可以引出诱发电位,振幅与对照组无显著性差异,诱发电位潜伏期呈现先延长后缩短的趋势。随着全切、结扎、半切、挫灭损伤程度不同,肌纤维平均直径及肌束直径逐渐增大,单位面积细胞核数逐渐减少。结论:不同损伤,肌电特征及声带运动状态呈动态变化,喉返神经的损伤程度依次为完全损伤、不完全损伤(结扎法、半切法、挫灭法),喉肌电图检查是声带麻痹诊断和评估的重要方法。

Objective：To investigate the electrophysiological characteristics and pathological changes in different recurrent laryngeal nerve injury models. Method： Twenty dogs were divided into different models of recurrent laryngeal nerve injury. Electrophysiological changes of animal models and histopathological changes in laryngeal muscles were investigated at different time. Result：Amplitude of MUP in TA decreased at first and then increased a little, while duration of MUP keeps decreased. The latent periods of the evoked potential in the incomplete injury group increased at first and then went down. In animal histopathological investigation, the lighter of the muscle injuried and the bigger of the diameter of muscle fibers and fascicles, and the smaller of the number of cellular nucleolus per square inch. In the early periods after injury, the correlation among the standard amplitude, threshold amplitude, maximum amplitude of EP and the diameter of fascicles were positive; while in the late period, the cor relation among the amplitude, duration, area of MUP and nucleolus number was positive. Conclusion：The physiological characteristics of laryngeal nerves and muscles could be known . LEMG was an important method in diagnosis of laryngeal nerve and muscle diseases.