title: Mechanics of the urethral duct: tissue constitutive formulation and structural modeling for the investigation of lumen occlusion.
abstract: Urinary incontinence, often related to sphincter damage, is found in male patients, leading to a miserable quality of life and to huge costs for the healthcare system. The most effective surgical solution currently considered for men is the artificial urinary sphincter that exerts a pressure field on the urethra, occluding the duct. The evaluation of this device is currently based on clinical and surgical competences. The artificial sphincter design and mechanical action can be investigated by a biomechanical model of the urethra under occlusion, evaluating the interaction between tissues and prosthesis. A specific computational approach to urethral mechanics is here proposed, recalling the results of previous biomechanical experimental investigation. In this preliminary analysis, the horse urethra is considered, in the light of a significant correlation with human and in consideration of the relevant difficulty to get to human samples, which anyway represents the future advance. Histological data processing allow for the definition of a virtual and a subsequent finite element model of a urethral section. A specific hyperelastic formulation is developed to characterize the nonlinear mechanical behavior. The inverse analysis of tensile tests on urethra samples leads to the definition of preliminary constitutive parameters. The parameters are further refined by the computational analysis of inflation tests carried out on the entire urethral structure. The results obtained represent, in the light of the correlation reported, a valid preliminary support for the information to be assumed for prosthesis design, integrating surgical and biomechanical competences.
authors.affiliation: Department of Industrial Engineering, University of Padova, Via F. Marzolo, 9, 35131, Padova, Italy. arturo.natali@unipd.it.|Centre for Mechanics of Biological Materials, University of Padova, Via F. Marzolo, 9, 35131, Padova, Italy. arturo.natali@unipd.it.
authors.forename: Arturo Nicola
authors.initials: AN
authors.lastname: Natali
authors.affiliation: Department of Industrial Engineering, University of Padova, Via F. Marzolo, 9, 35131, Padova, Italy.|Centre for Mechanics of Biological Materials, University of Padova, Via F. Marzolo, 9, 35131, Padova, Italy.
authors.forename: Emanuele Luigi
authors.initials: EL
authors.lastname: Carniel
authors.affiliation: Centre for Mechanics of Biological Materials, University of Padova, Via F. Marzolo, 9, 35131, Padova, Italy.|Department of Biomedical Sciences, University of Padova, Via U. Bassi, 58/B, 35131, Padova, Italy.
authors.forename: Chiara Giulia
authors.initials: CG
authors.lastname: Fontanella
authors.affiliation: Department of Industrial Engineering, University of Padova, Via F. Marzolo, 9, 35131, Padova, Italy.|Centre for Mechanics of Biological Materials, University of Padova, Via F. Marzolo, 9, 35131, Padova, Italy.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Frigo
authors.affiliation: Department of Industrial Engineering, University of Padova, Via F. Marzolo, 9, 35131, Padova, Italy.|Centre for Mechanics of Biological Materials, University of Padova, Via F. Marzolo, 9, 35131, Padova, Italy.
authors.forename: Silvia
authors.initials: S
authors.lastname: Todros
authors.affiliation: Centre for Mechanics of Biological Materials, University of Padova, Via F. Marzolo, 9, 35131, Padova, Italy.|Department of Biomedical Sciences, University of Padova, Via U. Bassi, 58/B, 35131, Padova, Italy.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Rubini
authors.affiliation: Centre for Mechanics of Biological Materials, University of Padova, Via F. Marzolo, 9, 35131, Padova, Italy.|Department of Animal Medicine, Production and Health, Viale dell'Università, 16, 35020, Legnaro (PD), Italy.
authors.forename: Giulia Maria
authors.initials: GM
authors.lastname: De Benedictis
authors.affiliation: Urology Clinic, Verona Integrated University Hospital, Piazzale A. Stefani, 1, 37126, Verona, Italy.
authors.forename: Maria Angela
authors.initials: MA
authors.lastname: Cerruto
authors.affiliation: Urology Clinic, Verona Integrated University Hospital, Piazzale A. Stefani, 1, 37126, Verona, Italy.
authors.forename: Walter
authors.initials: W
authors.lastname: Artibani
mesh_terms: D000818:Animals; D006736:Horses; D008297:Male; D055595:Mechanical Phenomena; D023421:Models, Animal; D008954:Models, Biological; D011474:Prosthesis Design; D014521:Urethra / Q000033:anatomy & histology / Q000502:physiology*; D014524:Urethral Obstruction / Q000150:complications / Q000628:therapy*; D016741:Urinary Sphincter, Artificial
keywords: Artificial urinary sphincter; Computational biomechanics; Experimental testing; Tissue mechanics; Urethral duct