IMPLANTABLE VOLUME MONITOR AND MINIATURIZED STIMULATOR DEDICATED TO BLADDER CONTROL

This paper describes a new miniaturized implantable bladder controller that is composed of 4 main parts: a volume monitoring device based on the tomography approach, a fully programmable miniaturized central pr ocessor and stimulator, a bidirectional data and power link, and an ex ternal controller. The proposed system is intended to restore both nor mal bladder functions (retention and voiding) to spinal cord injured p atients. The system contains a mixed-signal (analog/digital) feedback loop to command the bladder functions through neuromuscular stimulatio n techniques. The implantable circuitry is powered by a single encoded radiofrequency carrier and may have up to 8 independently controlled monopolar (4 bipolar) channels. The microstimulator is able to generat e a wide range of stimulation patterns, including selective stimulatio n waveforms. In addition, an optical link transmits the state of the i mplant and volume monitoring results to the external controller.