Retrograde Intrarenal Surgery for Renal Stones: Is It a Safe and Effective Option in Preschool Children?

Introduction: Few studies in the literature describe the Retrograde Intra-Renal Surgery (RIRS) outcome in preschool children. We evaluated the feasibility, stone -free rate and complications of RIRS in preschool children at two European tertiary care centres of Pediatric Urology. Material and methods: The retrospective study includes all children undergone RIRS for stones <25 mm from 2017 to 2022. Patients were divided into Group 1 <5 years (G1) and Group 2 >5 years (G2). Semirigid ureterorenoscope 4.5-6.5 Ch and a 7.5 Fr flexible ureteroscope with a 9.5/11 Ch ureteral access sheath (UAS) were used. Stone -free rate (SFR) was evaluated at 3 months. Fischer/Chi-square test for qualitative data and Mann -Whitney for quantitative data were used for statistical analysis. Results: 63 patients underwent RIRS, 19 G1 -patients, median age 3.55 +/- 1.06 years (range 1.5-5 years), and 44 G2 -patients, median age 11.25 +/- 2.95 (range 6-17 years) (p < 0.00001). Intraoperative complications occurred in 1 case in G1(5%) and 3 in G2(7%) (p = 1): two minor ureteric injuries in G2 were treated by a prolonged JJ-stent. Postoperative fever was reported in 3 cases in G1 (16%) and 4 in G2(9%) (p = 0.42), while post -operative hematuria in 4 G1 -patients (21%) and in 7 G2 -patients (16%) (p = 0.72). SFR was 84.2% in G1 and 88.6% in G2. At an average follow-up of 15.05 +/- 4.83 months in G1 and 19.95 +/- 10.36 months in G2, reintervention for residual stones was necessary in 3 cases in G1(16%) and in 6 cases in G2(14%) (p = 1). Conclusions: In a European country with low -volume pediatric stone centers, RIRS is a promising therapeutic option in young children as it offers acceptable stone -free rate and a low incidence of high-grade complications. Level of Evidence: III. (c) 2023 Elsevier Inc. All rights reserved.