兔腰神经根慢性压迫模型的建立

A model for chronic nerve root compression in lumber spine of the rabbit

目的 :制作腰神经根慢性轻度压迫模型。方法 :取纯种新西兰成年兔 16只 ,将 4只做神经定位解剖 ,12只随机分成 3组 :10天组、30天组和 180天组 ,每组 4只。将长 12mm ,内径 1.5mm ,外径 2 .5mm的硅胶管从椎间外孔缓慢塞入兔椎间管内 ,压迫腰 6和腰 7左侧神经根 ,右侧为自身对照侧 ,硅胶管的截面积约为椎间管经关节突关节矢状面面积的 2 0 % ,约为椎间外孔面积的 5 0 %。结果 :10天组与 30天组比较 ,潜伏时明显延长 ,神经传导速度减慢。180天组虽然与对照侧比较潜伏时和神经传导速度均有显著性差异 ,但与 30天组比较已有明显改善。对照侧的潜伏时、神经传导速度各时间点均无明显差异。除 10天组潜伏时、神经传导速度与对照侧比较无明显差异外 ,30天组和 180天组潜伏时、神经传导速度与对照侧比较均有明显差异 ,潜伏时延长 ,神经传导速度减慢。结论 :将硅胶管从兔的椎间外孔缓慢塞入椎间管内使腰神经根慢性轻度受压 ,更接近于腰椎间盘突出和椎间管狭窄对神经根的压迫。慢性压迫后的神经有自行恢复的能力。

Objective:To establish a model for chronic lumber nerve root compression and to observe the changes of chronic compressed lumbar nerve root in different periods. Method: 16 pure New Zealand rabbits were used among them four were dissected for nerve localization and the rest were randomly classified into three groups which were 10 -day group ,30- day group and 180 -day group. Electrophysiologic studies were made in all rabbits before killing them on demand. Compression model: Silastic tube was filled in intervertebral canal through extra inter- vertebral foramina and compressing the sixth and seventh left lumbar nerve roots. The tube had a length of 12mm, an inner diameter of 1.5mm, and an extra diameter of 2.5mm. Electrophysiological tests included latency period and nerve conduction velocity were analysed. Result: Compared with being compressed 10 days, the latency period was significantly longer and the nerve conduction velocity was significantly slower after 30 days. After 180 days, though the latent period and the nerve conduction velocity differed significantly from the control side, there were less changes than the 30-day group. There were no significant change on the latent period and the nerve conduction velocity of the control side depending on different times period. Meanwhile, compared with the control side,the latent period was significantly prolonged and the nerve conduction velocity was significantly decreased respectively after 30days and 180days. Conclusion: The chronic nerve root compressed model made in this article was more similar to what resulted from lumbar disc herniation and lumber nerve canal narrowing. Lumber nerve root could recover themselves after being slightly compressed .