Is flexible and navigable suction ureteral access sheath (FANS-UAS) the next best development for retrograde intrarenal surgery in children? Results of a prospective multicentre study.

Purpose: To assess retrograde intrarenal surgery (RIRS) outcomes in children using ClearPetra, a flexible and navigable suction ureteral access sheath (FANS-UAS).

Methods: Children with kidney stone(s) only undergoing RIRS in 8 centers were prospectively included (September 2023-May 2024).

Exclusion criteria: ureteral stone, bilateral procedures, anomalous kidneys, surgery for residual fragments. Lithotripsy was performed using either a Holmium or Thulium fiber laser. Postoperative pain was assessed within 24 h using a 10-point visual analogue score. The use of FANS-UAS was graded by surgeons after each case using a 5-point likert scale. Low-dose non-contrast CT scan was performed before and within 30 days of RIRS to assess residual fragments (RFs). Stone-free status was defined as no RF or single RF up to 2 mm.

Results: 50 children were included. 66% were male. Mean age was 6.6 (± 3.38) years. 88% stones were < 2 cm. one-third of the patients had a stone volume > 1500mm³. 10-12 Fr FANS-UAS was used in 98% of the procedure. The mean operative time was 46.02 (± 20.72) minutes. 2 patients had Traxer grade1 distal ureter and 2 forniceal injuries on sheath placement. Mean pain score was 2.18 (± 1.34). Mean likert scale was 1.16 (± 0.47) for ease of suction, 1.24 (± 0.52) for manipulation, 1.02 (± 0.32) for visibility. 4 patients had post-operative fever lasting less than 24 h. No sepsis occurred. Stone-free rate was 100%.

Conclusions: Our study shows that the use of FANS-UAS in paediatric RIRS is feasible and safe with a low rate of complications and excellent stone-free rate.