Investigation of interaction phenomena between lower urinary tract and artificial urinary sphincter in consideration of urethral tissues degeneration

Lower urinary tract dysfunction pertains to symptoms related to the lower urinary tract (LUT), with consequent incontinence. Artificial urinary sphincters (AUS) are adopted to obtain continence conditions, mainly in male subjects, via urethral occlusion by applying pressure load, mostly operating on the basis of an empirical approach. Considering the frequent access of elderly patients to this surgical practice, tissue degradation related to aging phenomena must be investigated. Computational models of the LUT structures and the AUS systems have been designed to evaluate tissues mechanical stimulation and degenerative phenomena for reciprocal interaction. Virtual solid models of the LUT have been developed starting from biomedical images, as histological/morphometrical data. Segmentation procedures have been exploited to provide the three-dimensional reconstruction, and subsequent discretization techniques led to the finite element model. Contemporarily, a finite element model of a typical AUS device was developed. Numerical analyses have been performed to analyze interaction phenomena between AUS and LUT. Different conditions were investigated, modifying both loading conditions, as intraluminal pressure and AUS action, and urethral tissues properties. Particular attention was devoted to tissues parameters, aiming to evaluate the influence of tissues degeneration because of aging and/or pathologies.