The objective of this program is the development of a magnetically operated artificial urethral sphincter (AUS). The chief advantages of the new AUS are: ease of use, safety, and reliability. The device is mechanically simple, and it also provides for non-invasive adjustment of urethral cuff pressure. Currently available AUS devices are difficult to use for many patients, have questionable mechanical reliability, and generally require surgical revision of the prosthesis to make even simple adjustments. The basic feasibility of new AUS was demonstrated in Phase I. In the Phase II program, the effect of pressure from the external magnet on the skin will be studied in detail. Three different contact pressure levels will be examined in experiments using miniature pigs as the animal model. Serum creatinine phosphokinase will be monitored as a biochemical index of skin injury during each study, and kin blood flow will be directly measured using a laser Doppler flowmeter. These experiments will define the range of safe operating pressures for the device. A second series of experiments using the canine animal model then will be performed to examine device operation in vivo for up to 1 year duration. Finally, methods for fabricating the new AUS at a cost comparable to currently available devices are to be implemented.
