Abstract: Objective · To estimate the efficacy and safety of flexible ureteroscopy combined with holmium laser lithotripsy in the treatment of upper urinary tract calculi in infants aged 3 years old and below. Methods · January 2016 to March 2019, the cases of infants aged 3 years old and below who were treated with flexible ureteroscopy combined with holmium laser lithotripsy for upper urinary tract calculi in Department of Urology, Shanghai Children’s Medical Center, Shanghai Jiao Tong University School of Medicine were collected. The double J (DJ) stents were placed in the cases for 0.5-3 months, followedflexible ureteroscopy combined with holmium laser lithotripsy after urinary tract infection was controlled. OLYMPUS flexible ureteroscope and 200 μm holmium laser fiber were used in the operation. Holmium laser power was 20-30 Hz/0.5-1.0 J according to the size and hardness of the stones, and then DJ stent was retained after retraction of the ureteroscope to finish the operation. Results · A total of 32 infants aged 3 and below with upper urinary tract stones were included in the study, including 21 males and 11 females, and the median age was 26 months (7-36 months). All 32 cases were successfully treated with flexible ureteroscopy combined with holmium laser lithotripsy. Among them calculi in 22 cases were removed after one operation, and the calculi-free rate after one operation was 68.8%. The median duration of operation was 53 min (15-110 min); the median hospitalization after operation was 3 d (2-12 d); the median days of DJ stent removal after operation was 60 d (18-100 d). Urinary tract infection occurred in 4 cases, and high fever with urinary tract infection occurred in 2 cases. Anti-infection and other symptomatic treatments were given respectively to improve the symptoms. Conclusion · Flexible ureteroscopy combined with holmium laser lithotripsy is effective and safe in the treatment of upper urinary tract calculi in infants, which can be widely used in clinic.

Key words: flexible ureteroscopy, holmium laser, infant, upper urinary tract calculi