Flexible ureterorenoscopy vs. mini percutaneous nephrolithotomy for kidney stones in chronic kidney damage: a prospective study

OBJECTIVES: Chronic kidney disease (CKD) poses unique challenges in the management of renal stones, and high-quality evidence to guide treatment decisions is limited. This study aimed to compare the effects of flexible ureteroscopy (f-URS) and mini-percutaneous nephrolithotomy (m-PCNL) on perioperative outcomes and long-term renal function in patients with CKD and renal stones. METHODS: This prospective randomized study included 60 CKD patients with renal stones measuring 1-4 cm. Participants were randomized into f-URS (n = 24) and m-PCNL (n = 36) groups. Baseline demographics, stone characteristics, and perioperative parameters were recorded. Stone-free rate (SFR) was defined as the absence of any residual fragments on postoperative computed tomography (CT) at 1 month. Renal function was assessed by estimated glomerular filtration rate (eGFR), serum creatinine, and CKD stage at baseline and 6 months. A post hoc exploratory subgroup analysis was performed for patients with 10-20 mm stones. RESULTS: Stone-free rates were comparable between groups (79.2% vs. 86.1%, p > 0.05). f-URS was associated with shorter operative duration, reduced fluoroscopy time, lower hemoglobin drop, and shorter hospital stay (all p < 0.01). At 6 months, median renal function values were more favorable in the f-URS group, with higher median eGFR (44.0 vs. 51.5 mL/min, p = 0.042) and lower creatinine (1.6 vs. 1.4 mg/dL, p = 0.031), whereas the changes from baseline (ΔeGFR and Δcreatinine) did not show a statistically significant difference. In the exploratory 10-20 mm subgroup results were statistically in favor of f-URS, but these findings should not be generalized due to the small sample size and post hoc nature of the analysis. CONCLUSIONS: Both f-URS and m-PCNL achieved similar stone clearance in CKD patients. f-URS may offer advantages regarding perioperative safety and renal function preservation, but these observations require confirmation in larger studies with long-term follow-up. Treatment decisions in this high-risk population should be individualized.