Microureteroscopy in the treatment of upper urinary tract stones in pediatric patients younger than 3 years of age.

The aim of this study is to evaluate the usefulness of microureteroscopy (m-URS) in the treatment of renal and ureteral stones in children younger than 3 years of age. A retrospective analysis of pediatric patients aged < 3 years with upper urinary tract calculi who underwent lithotripsy was performed. The children were divided into the m-URS group (4.85 F, n = 41) and the ureteroscopy (URS) group (4.5/6.5 F, n = 42) according to the type of ureteroscope used. The mean age of the patients was 23.5 ± 10.7 months in the m-URS group and 20.6 ± 7.1 months in the URS group (P = 0.212). The success rate of one-stage surgery was 80.5% (33/41) for m-URS and 38.1% (16/42) for URS (P < 0.001). The success rates of m-URS were 60.0%, 69.2%, and 91.3% for stones located in the renal pelvis/calix, upper ureter, and mid-lower ureter, respectively. Eight children in the m-URS group and 26 children in the URS group underwent the second-stage ureteroscopic surgery. The mean operation time was 50 (30-60) min in the m-URS group and 40 (34-60) min in the URS group (P = 0.287). The complication rates were 4.9% and 7.1% in the m-URS and URS groups, respectively (P = 1.000). The stone-free rate at 1 month after lithotripsy was 87.8% in the m-URS group and 83.3% in the URS group (P = 0.563). The mean anesthesia session was 2.1 in the m-URS group and 2.5 in the URS group (P = 0.002). M-URS can effectively reduce the number of anesthesia sessions and is considered an alternative treatment for upper urinary tract calculi in selected pediatric patients younger than 3 years of age.