基于腔内压力评价的植入式结肠电刺激系统设计与动物实验

Animal experiment of implantable electrical stimulation system in colon based on evaluation of cavity pressure

目的测试自行研制的植入式结肠起搏点电刺激系统对增加盲肠运动的效果。方法植入式结肠电刺激系统由植入式体内刺激器、便携式体外控制器和计算机参数设置分析软件组成。刺激参数及指令经体外控制器,以无线通信模式发送至体内刺激器;表征结肠收缩活动的压力信息由结肠腔内压力感受器采集后通过无线通信模式发送至体外控制器存储卡储存。选择46kg健康白猪1只,麻醉后开腹,将体内刺激器植入右侧腹股沟皮下,刺激电极穿过腹壁植入盲肠壁内固定,刺激参数选择电压为10、15、20 V,双脉冲频率为10、40、120 Hz,脉冲时间为0.5、1.0、3.0、5.0 ms,每次刺激前后连续观察记录5 min。检测完成后植入器固定,关腹后饲养1个月再次手术取出植入器。结果植入式结肠起搏点电刺激系统工作正常,在上述的电压、脉冲频率和双脉冲宽度的任意组合参数刺激下,发现电压和频率相同时脉宽越长,肠壁收缩活动的幅度越大;脉宽和电压相同时脉冲频率越高,肠壁收缩活动的潜伏期越短;频率和脉宽相同时电压越大,肠壁收缩活动的潜伏期越短,收缩幅度越大。在脉宽5.0ms、频率120Hz、电压15V的脉冲电刺激下,盲肠处于强直收缩状态。体内刺激器植入1个月,无感染及异物反应,取出时见植入物周围有少许包裹性积液。结论自行研制的电刺激系统初步适合进行结肠电刺激动物实验,选择合适刺激参数的结肠起搏点电刺激可明显增加结肠收缩运动,为进一步探索结肠电刺激治疗慢传输性便秘提供了研究基础。

Objective To study the effect of the self-developed implantable electrical stimulation system of colon pace maker for increasing the movement of cecum. Methods The system was composed of an implantable electrical stimulator, a portable external controller and computer parameter analyzed software. The stimulation parameters and instructions were made by computer program and downloaded to external controller and subsequently sent to the stimulator by wireless communication mode. The pressure information characterized the colon contraction was collected by pressure sensor within colon cavity and sent to the controller through wireless communication and stored into storage card for analysis. A healthy white pig with body weight of 46 kg was selected for the experiment. It was laparoscopie operated after anesthesia, and subcutaneously implanted with a stimulator on the right side groin. The stimulation electrode was fixed within cecal wall through abdominal wall. The stimulation parameters were set as followed： voltage was 10 V, 15 V and 20 V, respectively; double pulse frequency was 10 Hz, 40 Hz and 120 Hz, respectively; pulse duration was 0.5 ms, 1.0 ms, 3.0 ms and 5.0 ms, respectively; record time was 5 minutes before and after stimulation respectively. The stimulator was fixed after the experiment was finished and the abdomen was closed. The stimulator was removed by surgery after 1 month. Results The system of implantable stimulator operated normally. With combination of the above voltages, pulse frequency and double pulse width, it was showed that at the same voltage and frequency the pulse width was longer, and the co/on wall contraction amplitude was greater, at the same pulse width and voltage, the frequency was higher, and latency of cecal contraction was shorter, at the same frequency and pulse width, the voltage was higher, the latency of cecal contraction was shorter and contraction amplitude was greater. The cecum was in the state of titanic contraction at the condition of 5.0 ms, 120 Hz and 15 V. There was no any infection or foreign body reaction during the 1 month implantation experiment. There was only a little encapsulated effusion around the stimulator at removal. Conclusion It is demonstrated that the self--developed electrical stimulation system is primarily suitable for animal colon electrical stimulation. With suitable parameters of stimulation, the colon pace maker could remarkably increase the colon contraction movement. It supplies an experimental basis for further exploration of colon electrical stimulation treatment in slow transmission constipations.