High-quality evidence comparing supine to prone percutaneous nephrolithotomy (PCNL) for the treatment of complex stones is lacking. This study aimed to compare the outcomes of supine (SUP) and prone (PRO) PCNL. Materials and Methods:A non-inferior randomized controlled trial was performed according to the CONSORT criteria. The inclusion criteria were patients over 18 years of age with complex stones. SUP was performed in the Barts flank-free modified position. Except for positioning, all the surgical parameters were identical. The primary outcome was the difference in the success rate on the first postoperative day (POD1) between groups. The secondary outcome was the difference in the stone-free rate on the 90 th postoperative day (final SFR). A noninferiority margin of 15% was used. Demographic, operative, and safety variables were compared between the groups.Statistical significance was set at p<0.05.Results: Overall, 112 patients were randomized, and their demographic characteristics were comparable. The success rate on POD1 was similar (SUP:62.5% vs. PRO:57.1%, p=0.563). The difference observed (-5.4%) was lower than the predefined limit. The final SFR was also similar (SUP:55.4% vs. PRO:50.0%, p=0.571). SUP had a shorter operative time (117.9±39.1 vs. 147.6±38.8; p<0.001, minutes) and PRO had a higher rate of Clavien ≥ 3 complications (14.3% vs. 3.6%; p=0.045).

avoidance of pleura and visceral structures with needle puncture. As upper pole access may be limited due to rib shadowing, interpolar or lower pole calyceal punctures tend to be selected. This may be a foreseeable prerequisite for reliance on flexible nephroscopy for complex stone, but incorporation of thulium mitigates the inefficiency of flexible stone treatment. 1 A more lateral and downward trajectory of the renal sheath associated with supine access encourages drainage of stone fragments and, as the authors postulate, decreases intrarenal pressure which may explain better stone clearance and lowered rate of urinary sepsis. An upright seated posture for supine PCNL confers better ergonomics enjoyed by both surgeon and trainees. Lastly, familiarity with both supine and prone PCNL allows for flexibility of access when treating the toughest of cases.Ultimately, the selection of positioning will be based on the surgeon's training and comfort level, but I firmly predict a rising trend of supine PCNL with emergence of strong data as presented by the authors.