Percutaneous Nephrolithotomy Among Patients with Renal Anomalies: Patient Characteristics and Outcomes; a Subgroup Analysis of the Clinical Research Office of the Endourological Society Global Percutaneous Nephrolithotomy Study

Purpose: This study compared the characteristics and outcomes of percutaneous nephrolithotomy (PCNL) in patients with and without renal malformations using the Clinical Research Office of the Endourological Society (CROES) PCNL Global Study database. Patients and Methods: The CROES PCNL Global Study collected prospective data for consecutive patients who were treated with PCNL at centers around the world during 1 year. Patient characteristics, operative data, and outcomes of PCNL in patients with renal anomalies and those with normal kidneys were compared. Results: Of 5542 patients whose renal anatomy was recorded, 202 (3.6%) patients had a renal malformation. The most frequent anomalies were horseshoe kidneys (1.8%) and malrotated kidneys (1.3%). The prone position was the most frequently used position for patients with renal anomalies as was upper pole puncture. PCNL achieved stone-free rates of 76.6% in patients with anomalous kidneys and 76.2% in those with normal kidneys. The frequency of complications was similar in the two groups. Median operative time was significantly longer (87 min vs 75 min, P = 0.037), and access for PCNL was unsuccessful in significantly more patients (5% vs 1.7%, P = 0.001) in whom renal anomalies were present. Conclusion: In patients undergoing PCNL, the presence of renal malformation is likely to extend operative time. Stone-free rates as well as incidence of complications after PCNL are similar irrespective of the presence of renal anomalies.