Navigating Entire Collecting System During Supine Percutaneous Nephrolithotomy: Is Rigid Nephroscopy Enough? A Prospective Study by International Alliance of Urolithiasis Supine Percutaneous Nephrolithotomy Working Group.

Background: During percutaneous nephrolithotomy (PCNL), accessibility to the entire collecting system is crucial to check the presence of any residual stone fragments. In this study, we aimed to identify the rate of accessibility of all caliceal cavities using lower-, middle- and, upper-pole punctures and the eventual benefit of simultaneous utilization of retrograde/antegrade flexible nephroscopy. Materials and Methods: Data of patients undergone supine PCNL in five different institutions were collected prospectively. Access status to other poles of the kidney with a rigid nephroscope, antegrade access status to the other poles of the kidney with a flexible nephroscope, or retrograde access with a flexible ureterorenoscope were all evaluated together with detection of residual fragments. Access status to the other poles of the kidney with anterograde and retrograde approaches were compared. Results: Data of 226 patients were analyzed and stone-free status was achieved in 207 (91.6%) of the patients. The entire collecting system could be successfully approached by a rigid nephroscope in 50% of the cases through middle-pole puncture. This rate was significantly higher than that of lower-pole puncture (37.1%) and upper-pole puncture (28.1%) ( P  = .035). The successful approach to the entire collecting system with retrograde ureterorenoscopy was possible in 97.6% of the cases, while the successful approach was possible in 48 of the 60 cases (80%) with the retrograde approach ( P  < .0001). Conclusions: During PCNL, evaluation of the entire collecting system with rigid nephroscopy is not possible in a significant portion of the patients. We believe that the application of flexible nephroscopy, particularly via retrograde approach improves the stone-free rates.