Fluid dynamic investigations in the Urinary Tract

Urine flows in the urinary system from kidneys, where it is produced, until the 'outlet tube' which is called urethra.  Our research focusses on fluid dynamic investigations of urine flow in ureters, bladder and urethra in physiological and pathological conditions. Our latest research in this direction aims at improving the performances of existing ureteral stents.

Ureteral stents are medical devices that are clinically deployed to restore urine drainage in case of obstructions of the ureteral lumen, which can be either internal (e.g. kidney and ureteral stones) or external (urothelial carcinoma). Despite their wide clinical usage, stents suffer from several complications and side effects. These include irritation, pain, haematuria, and formation of encrusting and bacterial deposits. Encrustation and biofilm are considered the main causes of stent failure, and it has been shown that their development in stented ureters are strongly influenced by local fluid mechanics (e.g. shear stress).

The UGE group, funded by Swiss National Science Foundation, is building an in-vitro platform of the upper urinary tract which aims at improving the insight on the interplay between local fluid mechanics and encrustation in stented ureters. The platform has unique features as it mimics the physiological fluid-dynamic (pressure and flow) and geometrical environment inside the ureter allowing a full fluid mechanical characterisation. It consists of: i) a roller pump (to simulate the production of urine from kidneys) ii) a transparent ureter model and iii) a bladder compartment whose internal pressure can be controlled to simulate the physiological bladder pressures (during the filling and emptying cycles).

The platform is combined with an index matched fluid to allow Particle Image Velocimetry (PIV) measurements within the lumen of the ureter with and without stents.

In this research context, UGE is part of the ENIUS COST Action ‘European network of multidisciplinary research to improve the urinary stents’ and has well-established collaborations with the major research groups in the field.

Check ENIUS website for more information about our multidisciplinary and international network.