Percutaneous nephrolithotomy for removal of encrusted ureteral stents: a multicenter study.

Purpose: Encrusted ureteral stents are a challenging endourologic problem. We performed a multi-institutional review of percutaneous nephrolithotomy (PCNL) as primary treatment for encrusted stents.
Materials and Methods: We identified 36 patients who underwent PCNL for treatment of an encrusted stent. A retrospective review was performed to compile details of procedures and outcomes for these patients.
Results: In 36 patients, 38 renal units underwent PCNL for encrusted ureteral stents. The mean patient age was 47.1 years (±16.7), and the female:male ratio was 15:21. Mean stent indwelling time before removal was 28.2 months (±27.8). The reason for long indwelling time was reported in 25 cases; these reasons included "patient unaware stent needed to be removed" (17 cases), pregnancy (2 cases), other comorbidities (3 cases), and patient incarceration (3 cases). In 3 cases, the stent had become encrusted within 3 months of placement. Mean operative time was 162 minutes (±71). There were no major intraoperative complications, and no patients required blood transfusion. Litholapaxy was required for bladder coil encrustations in 22 cases (58%), and ureteroscopy with lithotripsy was required for encrustation of the ureteral portion of the stent in 13 cases (34.2%). Second look percutaneous procedures were required in 13 cases (34.2%). The stent was removed at the time of PCNL without need for concomitant or delayed ureteroscopy and/or cystolitholapaxy in 8 cases (21%). Ultimately, all stents were removed successfully. Patients were rendered stone free according to radiographs in 24 cases (63%).
Conclusions: In this multicenter review, PCNL is confirmed to be a safe and effective means of addressing the retained and encrusted ureteral stent. PCNL without ureteroscopy or litholapaxy was sufficient in a minority of cases (21%). Adjunctive endourologic modalities are often required, and the surgeon should anticipate the need for concomitant antegrade ureteroscopic laser lithotripsy and/or cystolitholapaxy. Although complete stent removal can be anticipated, residual fragments are not uncommon.