A Bionic Sphincter for Stress Urinary Incontinence: Design and Preliminary Experiments

The treatment of severe Stress urinary incontinence (SUI) SUI cases requires the implantation of an artificial urinary sphincter (AUS). The current gold standard AUS presents a number of well-reported complications, including: mechanical breakdown, urethral atrophy, and cuff erosion. Patients implanted with AUS have a difficult lifestyle with 60% requiring re-visitation and re-operation [1]. The work reported in this paper provides a promising solution for a smart artificial sphincter that minimizes urethral atrophy through automatic re-adjustment of the pressure applied on the bulbous urethra to provide continence dynamically controls the occlusion of the urethral cuff. The effectiveness of artificial urinary sphincters device in maintaining continence was tested on an in vitro set-up replicating the different parts of the urinary system. The final in vitro test bed consisted of a prototyped silicone bladder, a urethra and a ureter from the same material, along with a support system that houses these components for experimental characterization. The choice of silicone as the material for the phantoms used in the set-up was done after producing several models made from various polymers. It was found that the models made of a specific silicone with Shore hardness 2A were closer in terms of mimicking the mechanical characteristics of the muscles in the parts of interest. The contribution of this work is in providing an in vitro test bed that can be used by researchers to test the AUS systems they develop, by surgeons to practice implantation and by physicians to explain the surgical treatment to their patients. The test bed also represents an option to avoid animal experiments in preliminary testing.