Minimally invasive procedures are safer and more efficient compared to traditional open surgeries. The use of specialized endoscopic instruments for children minimize the possibility of complications.

In the first stage of treatment 4Fr double “J” was placed to left ureter. under general anesthesia. Antibacterial therapy was administered post-operation. After 10 days, the second stage of surgery was performed, which included retrograde rigid ureteroscopy on the left and mini-PERC with antegrade flexible ureterolithotripsy for impacted upper ureteral stone under general anesthesia.

Puncture of the renal calyx was performed under C-arm guidance, using the "bulls eye technique" with a rotation of the arc from 0 to 30 degrees. After the puncture a hydrophilic guide wire 0.035' was passed through the needle into the kidney. The puncture tract was dilated using a 8-10 Fr Teflon dilator over the guide wire. We used the "single-step dilation" (Karl Storz minimally invasive PCNL). This method reduces the radiation exposure for the patient, minimizes possible damage to the renal parenchyma, and reduces the operation time. Trough access sheath the single use flexible ureterorenoscope inserted and impacted upper ureteral sone is reached. The stone was fragmented using a holmium laser with a 200 μm laser fiber, 1-2J/15-20Hz (Quanta System Cyber Ho, Italy). The stone fragments were washed out using the irrigation, and larger fragments were removed using 2.7 Fr stone-basket. After fragment removal, the ureter and renal pelvis was visually inspected, and ureteral stent (double “J”) 4Fr-12cm was inserted into the kidney, after removing the ureteral catheter. The renal pelvis was examined for bleeding. The working sheath was removed under visual control. The procedure was completed without placing a nephrostomy tube.

Antegrade PCNL with using flexible ureterorenoscopes is a safe and effective option for large, impacted upper and middle-ureteral calculi.