An 18-months-old baby boy visited a local tertiary center due to persistent gross hematuria. He underwent renal ultrasonography which showed 28mm-sized RK renal stone and LK small stones.

He was finally referred to my hospital for checking the feasibility of ultraminiperc.

Low-dose non-contrast CT showed RK renal stones. Radiopacity was poor. I decided to perform ultraminiperc (UMP) using a 12Fr sheath with a 8.5Fr miniaturized nephroscope. I am the only surgeon to perform UMP in Korea until now.

NCCT: RK pelvis (11x10x10mm), RKLPost (x1, 2x2x2mm), mild hydronephrosis, HU 1303. No LK stone.

The stone was completely removed and the wound was so small to be identified.