Ureteral stent encrustation. Pathophysiology.

Ureteral stents are the most commonly used urological implants. They are used for temporary as well as for long-term ureteral stenting. Amongst others, complications of ureteral stenting are encrustation and cellular adherence which, in turn, promotes urinary tract infection and can induce impaired healing in case of ureteral damage. Biofilm formation on urological implants leads to the protection of persisting bacteria from local defense mechanisms, thereby rendering persistent urinary tract infections more common. It seems clear that antibiotics cannot penetrate into biofilms adequately. Also, bacteria persist in biofilms in a state of reduced metabolism which further reduces antibiotic efficacy. Furthermore, bacteria develop resistance more quickly in biofilms. This paper tries to give an overview of the complex pathophysiological mechanisms that underlie stent encrustation as far as we know to date.