Flexible Ureteroscopy with a Tip-Flexible Pressure-Controlling Ureteral Access Sheath for Renal Stones in Children

Introduction: The aim of this study was to evaluate the safety and efficacy of flexible ureteroscopy using a tip-flexible pressure-controlling ureteral access sheath (TFPC-UAS) for renal stones in children. Methods: Consecutive patients aged 5-18 years with renal stones of diameter 1-3 cm were enrolled between January 2022 and November 2023 at Ganzhou People's Hospital. The patients were treated with flexible ureteroscopy using the TFPC-UAS. The renal pelvic pressure (RPP) parameters were set as follows: control value at -10 mm Hg to 5 mm Hg, warning value at 20 mm Hg, and limit value at 30 mm Hg. The infusion flow rate was set to 100-120 mL/min. A holmium laser (276 mu m) was used to fragment the stone at 2.0-2.5 J/pulse with a frequency of 20-30 pulses/s. The cases were analyzed for RPP, operative time, stone-free rate, and complications. Results: A total of 21 consecutive patients were included. Two patients were switched to percutaneous nephrolithotomy owing to sheath placement failure. The RPP was -4.6 +/- 2.1 mm Hg. The mean operative time was 56.5 +/- 17.1 min. The postoperative hospitalization time was 1.5 +/- 0.3 days. The stone-free rates at 1 day and 1 month after surgery were 81.0% and 85.7%, respectively. Residual stones in 2 patients were cleared after extracorporeal shockwave lithotripsy. Three cases of Clavien I complications and one case of Clavien II complications occurred. No major complications (Clavien grade III-V) were observed. Conclusions: Flexible ureteroscopy with a TFPC-UAS is safe and effective for renal stones in children.