Surgery
The procedures were performed by 5 surgeons highly experienced in laser lithotripsy (who had performed at least 50 procedures prior to the start of this study). According to local clinical practice, all patients were “pre-stented” 4–7 days before the procedure, prior to the subsequent use of a ureteral access sheath (12–14 Fr, Cook, USA, and 11–13 Fr, Navigator HD, Boston Scientific, Marlborough, USA). RIRS was performed under general anesthesia in the lithotomy position. The lithotripsy settings were based on previous research completed on the topic [According to our previous research, the most efficient regimens for stone ablation were suggested (fragmentation (1.5 J × 20 Hz), dusting (0.5 J × 30 Hz) or popcorning (0.15 J × 100 Hz)). However, surgeons could adapt the regimen to their own needs if necessary [