诱发电位在马尾神经压迫损伤中的应用

Application of lumbar potential recording in monitoring the development and reversion of cauda equina syndrome

目的 探讨腰段诱发电位在马尾神经压迫损伤中的应用及意义。方法 将导管胶囊轻柔插入兔L7慢性压迫马尾神经 ,将 2 3只兔随机分为对照组 5只和压力值分别为 1.93 4kPa的实验Ⅰ组和2 .2 13kPa的实验Ⅱ组各 9只 ,每组按 1周、2周、4周时减压 ,用诱发电位仪观察 1个月。结果 随着椎管狭窄越重、压迫时间越长 ,诱发电位的潜伏期呈进行性延长 ,波幅不断下降 ,马尾神经损害由功能性改变发展为器质性改变。实验Ⅱ组较实验Ⅰ组更明显 (P <0 .0 1) ,压迫 4周组较压迫 1周组更明显 (P <0 .0 1)。马尾神经功能恢复的优劣取决于马尾神经损害的程度和减压时机的早晚 :实验Ⅰ组马尾神经功能恢复明显优于实验Ⅱ组 ( P <0 .0 1) ,1周时减压明显优于 4周时减压 ( P <0 .0 1)。结论 根据腰段诱发电位的改变可以判断马尾神经损害程度及神经功能恢复情况 ,手术减压时间越早 ,疗效越好。

Objective To probe into the clinical significance and application of lumbar potential in assessment of compression injury of cauda equina. Methods Twenty three rabbits were randomly divided into three groups, with eighteen animals each being assigned to two study groups and five to a control group. A balloon catheter was lightly inserted into the vertebral canal of the rabbit at L 7 level, with cauda equina being compressed by the balloon at a pressure value of 1.934 kPa in the study group Ⅰ, at 2.213 kPa in the study group Ⅱ, and subjected to no compression in the control group. Decompression surgery was performed 1, 2 and 4 weeks postoperatively for the study groups, and all three groups were monitored at regular intervals for a period of 1 month using an evoked potential apparatus. Results The latency increased progressively and the amplitude decreased with aggravated vertebral canal stenosis and prolonged compression of cauda equina; at the meantime, the functional impairment evolved into a structural one.Thus study group Ⅱ showed more severe injury rather than study group I(P< 0.01 ), and the four week compression group more obvious than the one week compression group (P< 0.01 ). The extent to which functional recovery could be achieved was dependent on how severe an injury cauda equina had sustained and how soon the decompression surgery was performed, as evidenced by much more satisfactory recovery for study group Ⅰ than for study group Ⅱ(P< 0.01 ), and much better results were obtained in the one week decompression group when compared with the four week compression group(P< 0.01 ). Conclusion The severity of compression injury of cauda equina and its functional recovery are predictable based upon the changes in lumbar potential, and the earlier the decompression, the sooner and more complete its functional recovery.