[The biocompatibility of catheters and stents used in urology]

Biocompatibility can be interpreted as the optimal combination of a series of interactions occurring at the material-tissue interface as soon as these two systems are in contact. It is a multifactorial interface property which integrates all of the phenomena involved in a biological environment i.e. absence of toxicity of the material for the body and absence of degradation of the material by the body. Biocompatibility can be evaluated in a normative context by using in vivo techniques in animals or in vitro techniques using cell cultures allowing the study of cytotoxicity (related to a concept of safety) and cytocompatibility (related to biological acceptability) of a material. Because of their intimate contact with the urothelium throughout implantation, the biocompatibility of catheters and stents constitutes a major requirement. This review presents the current data reported in the literature concerning the evaluation of the biocompatibility of materials used in urology. The main problems encountered are alterations of the urothelium, such as erosions or, on the contrary, mucosal hyperplasia, and the existence of incrustations developing on these materials.