Development of Implantable Electrode for Functional Electrical Stimulation.

功能电刺激（FES）系统在恢复脊髓损伤和脑病患者瘫痪肢体的运动功能方面是非常有效的。申请者已被开发为经皮肌内电极刺激器，并已在临床上使用该系统。然而，该系统存在不可避免的问题，如电极穿过皮肤部位的感染和破损，日常维护要小心，对患者的美容不利。因此，开发完全植入的FES系统是必要的。在这项研究中，已经开发出比目前的经皮电极更可靠的电极。得到的结果如下：1。采用电渣重熔法制备铬钴合金，并拉制直径为25微米的钢丝和SUS316L不锈钢。力学性能得到了满意的结果。采用电流加速腐蚀试验，在盐水溶液中观察到SUS316L钢丝的点蚀现象，而604PH钢丝没有点蚀现象。为了在工作过程中方便、稳定地将电极与刺激器连接在一起，对连接器和电极尖端进行了设计。将两种材料（SUS316L和604PH）电极全植入FES的原型系统植入绵羊体内，并对系统进行了运行检查。期望为最终系统的开发提供有用的信息。

The functional electrical stimulation (FES) system is very effective in order to restore motor functions of the paralyzed extremities in spinal cord injury and carebral disease patients. The applicants have been developed as stimulator with percutaneous intramuscular electrodes and have been utilizing clinically the system. However, this system has unavoidable problems such as infection and breakage at the position where electrodes go through skin, careful daily maintenance, and cosmetically unfavorable upon patients. Therefore, development of a totally implanted FES system is necessary. In this study more reliable electrodes have been developed than the present percutaneous electrodes. The obtained results are as follows :1. Chromium-cobalt alloy was refined by electro-slag remelting and 25 mum diameter wire was drawn as well as SUS316L stainless steel. The mechanical properties were well satisfied.2. Pitting corrosion was observed on the SUS316L wire in saline solution with accelerated corrosion test by applying electric current, on the contrary, no pitting corrosion on the 604PH wire.3. In order to easily and stably connect electrodes with the stimulator during operation, design of connectors and electrode tip were developed.4. Prototype systems of totally implanted FES with the electrodes of two kinds of materials (SUS316L and 604PH) were implanted in sheep and operating check of the system has been carried out. Useful information has been expected for development of the final system.