Ureteral Stent Encrustation, Incrustation, and Coloring: Morbidity Related to Indwelling Times

Background and Purpose: Ureteral stents are a fundamental part of many urologic procedures. Serious complications, including migration, fragmentation, and stone formation, still occur, especially when stents have been forgotten for a long time. No widespread consensus for the type or indwelling time to avoid ureteral stent complications has been reached, however. We investigated the correlation between the indwelling time and encrustation, incrustation, coloration, and resistance to removal. Patients and Methods: A total of 330 ureteral stents in 181 patients were examined. Results: Overall, 155 (47.0%) stents were encrusted, and the encrustation rate was 26.8% at less than 6 weeks, 56.9% at 6 to 12 weeks, and 75.9% at more than 12 weeks. A total of 46 (13.9%) stents resisted removal, and 3 of these could not be removed by cystoscopy. The median indwelling time was 72 (14-124) days for stents that resisted removal and 31 (30-60) days for irremovable stents. The frequency of encrustation with coloration was higher than that without coloration in the period of less than 6 weeks and the period between 6 to 12 weeks of indwelling time. Conclusions: In our study, although ureteral stent encrustation was related to the indwelling time, heavily encrusted ureteral stents necessitating additional procedures for removal occurred within an indwelling time of 3 months. The exact interval for removal of an indwelling ureteral stent to avoid additional procedures for removal is therefore difficult to determine.