Management of nephrolithiasis in pelvic kidneys: comparative outcomes of contemporary surgical modalities from 11 high-volume centers

Purpose: To evaluate the effectiveness and safety of current surgical modalities for nephrolithiasis in ectopic pelvic kidneys, a rare congenital anomaly with limited available evidence. Methods: A multicenter retrospective study was conducted across 11 high-volume international centers, including 45 patients with congenital pelvic kidneys who underwent flexible ureteroscopy, multimodal-guided percutaneous nephrolithotomy, and laparoscopic pyelolithotomy. Stone-free rate (defined as 0 mm), need for ancillary procedures, and complications (Clavien–Dindo) were assessed. Results: Stones were classified as GUYS II in 51.1% of patients and GUYS III–IV in 48.9%. flexible ureteroscopy was the most common primary treatment (51.1%), followed by multimodal guided - PCNL (33.3%). Multimodal-guided PCNL achieved the highest stone free rate (86.7%) and the lowest requirement for ancillary procedures (OR 9.7; 95% CI 1.8–51 compared with other modalities). The overall final stone free rate for the cohort was 65.9% after a mean of 1.38 procedures per patient. Complications occurred in 13.3% of cases, with only one major event (Clavien-Dindo IVa). Conclusions: Our findings indicate that multimodal-guided PCNL achieved the highest success rates and required fewer ancillary procedures than other approaches when treating stones in ectopic pelvic kidneys. In contrast, flexible ureterorenoscopy showed lower efficacy and required more ancillary interventions. Complication rates were low and comparable to those observed in anatomically normal kidneys. Although larger cohorts would strengthen these observations, the very low incidence of ectopic pelvic kidneys inherently limits the ability to accumulate large patient numbers.