The Current Situation and Prospects for Urinary Stents

The aim of this book is to provide a multidisciplinary overview of an area of knowledge that affects a multitude of patients worldwide on a daily basis and that unfortunately shows a slow technological development. The main reasons for the lack of innovation in the development of urinary stents and catheters are, on the one side, the characteristics of the urinary tract, urine and the particularities of the research groups involved. The urinary tract shows challenging characteristics for the placement of urinary stents and catheters, both at the level of the upper and lower urinary tract. The peristalsis, the urinary microbiome, the ease of biofilm formation on the surface of urinary medical devices, as well as the changes that occur when placing a ureteral stent such as invalidation of the anti-reflux system of the ureterovesical junction, and the high sensitivity of the bladder trigone cause manifest drawbacks in patients. On the other hand, urine is a fluid supersaturated with mineral salts, which represents a very hostile environment for biomaterials, both polymeric and metallic, leading to a series of side effects with stents and catheters that favour encrustation and bacterial contamination. This leads to the failure of these medical devices in daily clinical practice. In addition to all these limitations, which make the urinary tract a complicated area for innovation in indwelling medical devices, the research groups involved in the improvement of these devices are composed of a small number of researchers and are groups generally isolated from each other. It is logical to think that the possibility of improving urinary stents and catheters will come from a wider and mainly multidisciplinary approach, as many different disciplines are needed to overcome the current pitfalls. Not only urologists are important, because although they are the ones who know the limitations of the current urological armamentarium, technological development is also the responsibility of other areas of knowledge. These include bioengineering, chemical engineering, microbiology, experts in coatings, in new polymers, in biomaterials, translational researchers, experts in new metal alloys, etc. And to this large group of researchers it is also necessary to include physicists, mathematicians and experts in an area that affects the urinary tract and the medical devices that are placed inside it, which is fluid dynamics.