颞骨骨折性面瘫手术减压时机的实验研究

Surgical opportunities on facial nerve decompression following intra-temporal facial nerve injury:an experimental study

目的制作颞骨骨折性面瘫的动物模型,初步探讨大鼠面瘫的自然发展过程,了解不同手术减压时机面瘫的治疗效果及减压后面瘫的恢复变化过程。方法选用Wistar大鼠32只,制作颞骨骨折性面瘫动物模型。将完全面瘫的大鼠随机分成4组:对照组即不减压组,2周减压组,4周减压组,8周减压组。分别于以上不同的时间行面神经减压术,并于不同时间测定面神经刺激阈值,以观察面神经的恢复情况。结果对完全面瘫的大鼠于面瘫后1周行面神经阈值检查,对最大电流刺激(3mA)无反应。4组大鼠面神经刺激阈值的恢复速度相比,2周、4周减压组比不减压组及8周减压组快;2周减压组面神经的恢复速度比4周减压组快。结论通过血管钳钳夹大鼠的面神经骨管,可以造成颞骨骨折性面瘫的大鼠模型。面神经减压术在面神经受损后4周内进行,可缩短其面神经阈值的恢复时间;且减压时间越早,面神经的恢复速度越快。

Objective To establish animal models of intratemperal facial nerve injury and find the natural developmental features of facial nerve injury. To explore the best time to do facial nerve decompression surgeries and to discover the laws of injured facial nerve recovery after the decompression surgeries. Methods 32 200-300 g female Wister rats were used, and the tympanic segments of the bone canal of the facial nerves were compressed by minimal forceps. After making the models, rats were randomly divided into 4 equal groups which were given decompression surgery at different times： within 3 weeks group, after 4 weeks group, after 8 weeks group and the control group. In the control group nothing was done. Decompression consisted of removing the crushed bone pieces and incising the epineurial sheath at the above-mentioned times. The facial nerve threshold current was measured using the NIM-Respense to observe the recovery of the facial nerve at intervals of 4 weeks. Results The complete paralysis rats had no response to the maximal current （3mA） in the first week. No significant difference was found between the control group and the group which had decompression surgery after 8 weeks（ P 〉 0.05）, but a difference between the other groups and the control group was found （ P 〈 0.05 ）. There were significant differences among the three surgery groups （ P 〈 0.05 ）. Conclusions Crushing the facial nerve bone canal by minimal forceps is a reasonable method to make the animal models of intratemperal facial nerve injury. Decompression of the facial nerve performed within two months resulted in a faster recovery of the threshold current. Decompression later than two months had the same recovery speed as no decompression of the facial nerve. During the first two months, the earlier the decompression of the facial nerve was performed, the faster the facial nerve recovered.