Objectives. We present data concerning an artificial implantable mechanical urinary sphincter that was designed to eliminate the inherent problems of the current hydraulic artificial urinary sphincter (American Medical System [AMS] 800). Our goal was to design a sphincter that creates urethral compression similar to the AMS 800 but creates the force without the use of fluid, thereby eliminating as much as 50% of the reoperations seen with the AMS 800, which occur because of fluid-related malfunctions. Methods. An implantable artificial mechanical sphincter consisting of a compressive coil encompassed in a polytetrafluoroethylene sheath was devised and tested in 6 live mongrel dogs to establish compressive force versus bladder pressure data, so as to provide data to create a mechanical sphincter for use in humans. Results. A direct relationship between bladder leakage pressure and cable tension force was demonstrated in all 6 experimental animals, thereby creating a mathematical equation that can be used by mechanical engineers to design a mechanical sphincter for use in humans. Conclusions. This study demonstrated that a mechanical urinary sphincter can be created that will provide continence and eliminate the problems associated with the hydraulic aspect of the AMS 800. In doing so, nearly 50% of the reoperations seen with the current AMS 800 can be eliminated, thereby improving the quality of life of patients for whom an artificial urinary sphincter is indicated.
Bibliographical noteFunding Information:
This study was supported by the Timm Research Company, Eden Prairie, Minnesota.
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