Ureteral stent encrustation: evaluation of available scores as predictors of a complex surgery

The morbidity and complications associated with use of internal polyurethane ureteral stents in a series of 290 stone patients treated endourologically or with extracorporeal shock wave lithotripsy were retrospectively reviewed. Of the 299 stents retrieved 141 were also tested for patency to relate the rate of luminal blockage with stent caliber, indwelling time and clinical evidence of obstruction in the stented tract. Stent indwelling times ranged from a few days to 18 months: 11.3% were indwelling longer than 6 months and 1.9% were lost to followup. Incrustation occurred in 9.2% of the stents retrieved before 6 weeks, 47.5% indwelling 6 to 12 weeks and 76.3% thereafter. In 19 cases over-all (6.4%) an auxiliary procedure was required to decrease incrusted stone burden and enable stent retrieval. Other complications included stent migration (3.7%), infection (6.7%) and breakage (0.3%). Despite a 30% rate of luminal blockage in stents retrieved after indwelling times up to 3 months, the incidence of clinical obstruction in stented tracts up to 3 months was 4%, confirming other reports that significant urine flow occurs around rather than through hollow, vented stents. Our findings underline the importance of restricting the use of stents to stone patients who will be reliable at followup. Morbidity was minimal if stent indwelling times did not exceed 6 weeks.

The management of the forgotten, encrusted, calcified (FECal) Double-J ureteral stents can represent one of the most difficult and challenging surgical conditions for the practicing urologist. We present a novel and simple grading system for the FECal stent and, taking into account our own experience and literature review, propose an algorithm in the management of the encrusted stent based on this new system.

Encrustation is a common phenomenon that can occur following placement of a ureteral stent into the urinary tract, and it can lead to serious complications. The following review addresses the mechanism of encrustation, the management of these stents and the newest technology developed to mitigate this issue.