The general purpose of this project is to study the technical feasibility of an implantable nerve stimulator for bladder control in patients with paralysis. The stimulator can generate current pulses of a special waveform to achieve selective activation of the small nerve fibers innervating the bladder wall, without causing simultaneous activation of the large fibers innervating the urethral sphincter. This requirement is normally difficult to accomplish because the two types of nerve fibers are intermixed in the same nerve trunk and the smaller-diameter fibers for the bladder usually have higher excitation threshold to electrical stimulation. The specific aims of the feasibility study are to establish system requirements for the projected clinical application, to complete conceptual design for the implantable stimulator and its external controller, and to evaluate the performance of the two critical circuits for the implant, the waveform generator, and output driver. The achievement of these objectives will provide a basis for evaluating the overall feasibility of the project and identify technical challenges for prototype device development. Once this device is made available for clinical application, it may greatly improve the quality of life and reduce the cost of medical care in the targeted patient population.The potential commercial application as described by the awardee: The stimulator will be useful for patients with spinal cord injury and other neurological disorders. There are approximately 220,000 spinal cord injured patients in the United States. The most likely candidates for this device are the 50 percent of paraplegics who suffer from chronic urinary tract infections due to incomplete voiding.
