Percutaneous genitourinary interventions in children were first described in 1981 and have evolved significantly over the years with the introduction of ultrasound (US) guidance and new and improved access devices ( 1 Ball Jr., W.S. Towbin R. Strife J.L. Spencer R. Interventional genitourinary radiology in children: a review of 61 procedures. AJR Am J Roentgenol. 1986; 147 : 791-796 , 2 Elyaderani M.K. Kalinowski D. Gabriele O.F. Percutaneous nephrostomy by pigtail catheter in children. South Med J.