Active_comparator: Using FANS

After the successful induction of anesthesia, the lithotomy position will be adopted. Ureteroscopy will be used with the aid of a safety guidewire to evaluate the condition of the ureter. The serial dilation of the ureter using ureteral dilators up to 14 Fr . The FANS will be then inserted into the ureter under the guidance of the safety guidewire. The FANS tip will be positioned in the renal pelvis or calyces near the location of the stone.~The FANS will be connected to a vacuum device, and the negative pressure will be applied. The actual intraoperative negative pressure value will be adjusted by the urologist through a pressure adjustment vent as needed. The irrigation volume was set using peristaltic pumps. Lithotripsy will be conducted using the holmium: yttrium aluminum garnet laser applying the dusting technique of laser lithotripsy. During lithotripsy, the FANS will allow us to retrieve most of the fragmented stone particles by application of the suction pressure. All cases w

Active_comparator: Using traditional UAS

The method of anesthesia, patient positioning, ureteral dilation, and lithotripsy were the same as those used in the FANS group.~For the traditional UAS group, the end of the UAS will be positioned underneath the ureteropelvic junction (UPJ). The irrigation volume is applied using peristaltic pumps. The dusting technique of laser lithotripsy will be applied to the stones.~All cases will be stented using JJ stents with the suitable size.