低频电刺激对脊髓损伤后膀胱过度活动抑制的仿真研究

Simulation Research on Inhibition Effect of Overactive Bladder After Spinal Cord Injury Using Low Frequency Electrical Stimulation

目的 探讨低频脉冲（0～10Hz）刺激时,不同刺激波形对脊髓损伤后逼尿肌反射亢进诱发的膀胱过度活动症的结果,以寻求抑制膀胱过度活动的最优刺激波形.方法 首先根据McNeal的神经纤维电缆模型,基于Frankenhaeuser-Huxley （FH） 方程建立有髓神经纤维的膜外点电极刺激的仿真系统,评价低频电刺激中的四种波形,即正向脉冲、负向脉冲、双向对称脉冲、双向不对称脉冲的效果.通过电刺激脊髓损伤犬的阴部神经实验,验证仿真条件下最优刺激波形的临床效果.结果 仿真实验表明双向不对称脉冲的抑制效果最佳;动物实验表明以3V、0.1ms的正向脉冲为起始脉冲,结合1V、0.3ms的负向脉冲的双向不对称波形的抑制效果为最优.结论 低频脉冲刺激脊髓损伤犬阴部神经时,正向脉冲在前的双向不对称脉冲的刺激波形仿真效果最佳,并适用于临床实验,能够有效抑制膀胱过度活动,保护神经避免电化学损伤.

Objective To investigate the effects of various stimulus waveforms in low frequency （0 - 10Hz） on the inhibition of overactive bladder, caused by detrusor hyperreflexia after spinal cord injury, and find a new stimulus waveform which can inhibit the bladder overactivity effectively. Methods According to the McNeal＇ s lumped circuit model theory of the myelinated axon, a simulation system based on the Frankenhaeuser-Huxley （FH） equations was built at first, to study the nerve fiber＇ s responses of several stimulus waveforms. Four kinds of stimulus waveforms were anodal pulse, cathodal pulse, biphasic symmetrical pulse and biphasic asymmetrical pulse. The clinic performance of the best stimulus waveform from the simulation results was also validated by stimulating pudendal nerve of the male Beagle dogs, which were spinal cord injured. The simulation results demonstrated that biphasic asymmetrical pulse was the best stimulus pattern in the low frequency stimulation. Results From the animal experiment, the results also showed that the anodal-leading, biphasic asymmetrical pulse, which is composed of anodal pulse in 3V, 0. lms and cathodal pulse in stimulation effect IV, 0. 3ms, Conclusion For had the best pudendal nerve electrical stimulation, the anodal-leading, biphasic asymmetrical stimulus pattern has thebest simulation result, and is possible to apply in the clinic, which can inhibit overactive bladder effectively, and protect the nerve fiber from electrochemiscal injury.