Abstract: Objective： To evaluate the development, safety and efficacy of percutaneous nephrolithotomy(PNL) for management of upper urinary tract calculi in pediatric patients. Methods: In the study, 77 pediatric patients undergoing 87 PNLs through mini or standard tract for upper urinary tract calculi between January 2005 and December 2016 in Peking University People’s hospital were reviewed, including 69 renal calculi, 6 upper ureteral calculi, 12 renal and upper ureteral calculi, 35 single calculi, 43 multiple calculi and 9 staghorn calculi. The development and efficacy of PNL in pediatric patients were studied by analyzing the characteristics and clinical indexes, and by reviewing the associated literature. The Clavien classification system was used to evaluate the complications after PNL. Results: A total of 87 PNLs were performed in 77 pediatric patients. Eighty-one upper urinary tract calculi were managed through a single tract(93.1%), 5 pediatric patients were managed through 2 tracts(5.7%), and 1 pe-diatric patient was managed through 3 tracts(1.2%). The mean operating time was (77.0±29.8) min. The stone-free rate after one session was 100% for single calculi and 71.2% for multiple or staghorn calculi, 5(5.8%) children underwent auxiliary procedure to remove the residual calculi and the final stone-free rate of PNL was 88.5%. One of the main complications of pediatric PNL was fever. Sixteen(18.4%) had moderate fever(38-39 ℃), 5(5.7%) had high fever(39-40 ℃) and there were no severe complications of infection, such as sepsis or septic shock. The mean hemoglobin loss was （10.3±16.1） g/L and the serum creatinine rise was (7.0±13.3) μmol/L. One(1.2%) pediatric patient suffered ureteroscopic lithotripsy because of the obstruction by the residual stone in ureter. No injury of organs or retroperitoneal urinary extravasation occurred. General assessment of the complications showed Clavien grade Ⅰ complications in 14 (16.1%) pediatric patients, grade Ⅱ in 7(8.0%) children and grade Ⅲ in 1(1.2%) children. There was no grade Ⅳ or Ⅴ complications. The overall complication rate was 25.3%. Conclusion: PNL for management of upper urinary tract calculi in pediatric patients is effective. Complications after PNL, as assessed with Clavien classification system, are mild and PNL in pediatric patients is safe.

Key words: Pediatric urolithiasis, Percutaneous nephrolithotomy, Clavien classification system, Complication.