Study On The Key Techniques For Bladder Function Rebuilding Based On FES

A high proportion of patients with spinal cord injury above sacral section are suffering from neurogenic bladder, which severely disturbs the life quality and is one of main cause of death for such patients. Since the traditional methods cannot completely cure most of the patients, the rebuilding method based on FES (functional electrical stimulation) is widely used. But there is no device for sacral root stimulation, which has full proprietary intellectual property rights and can fulfill directly clinical use, in China.Considering this background, our research team designs a system for transcutaneous wireless stimulation of sacral root to rebuild motor function of bladder. Its mechanism is to stimulate the anterior sacral root to achieve the contract of detrusor and use the strategy of post-stimulus voiding and prefatiguing sphincter to alleviate the dissynergy between detrusor and external urethral sphincter. This system is composed of a control box, a transmitting module and a receiving module. The control box is used for user interaction and generation of stimulation, fulfilling the stimulation strategy of sacral anterior root stimulation; the transmitting module modulates the stimulation signal, while receiving module demodulates it and transmits it to the electrode. The thesis demonstrates the design of hardware and software of control box.The thesis uses STM32f103ZET6 as the core of the control box and design the modules of control box, including:multi-channel and gate, USB virtual serial port, digital-controled boost power source, LCD touch screen. These modules are integrated on PCBs and enclosed in an enclosure. As for the design of software, the designed software encompasses the program for calibration of the boost power source and the program for real use. The program for real use realizes the function of the display, adjustment, save and recall of stimulation parameters as well as the start of stimulation by transplanting the operation system of μC/OS-Ⅱ.After completion of hardware and software design of the control box, the test of the complete system is carried out, which includes the test of signal charateristics, test under different media, as well as animal experiments. The results shows that the transcutaneous wireless system for sacral root stimulation can fulfill the multi-channel transcutaneours wireless FES on the condition that the receiving module is placed 4-cm beneath the skin.Also, an implantable bladder pressure sensing system prototype is designed for the monitoring pressure inside bladder. After proof of its feasibility, the system design and hardware design of this prototype are performed. The pressure calibration test shows that this prototype achieves the functions of accurate pressure sensing and the wireless transmition of the measurements.