Safety and efficacy of retrograde intrarenal surgery in primary and residual renal calculi in children

Background Minimal invasive approach is the current standard of care in the management of pediatric renal calculi. Current guidelines are clear with extra corporal shock wave lithotripsy (ESWL) and percutaneous nephrolithotomy (PCNL) for stone size less than and greater than 20 mm respectively. Although retrograde intrarenal surgery (RIRS) is well established in adults but literature on its role, safety and efficacy in children is sparsely available. Objective To share our experience of RIRS and its outcome in a pediatric population in both primary and residual calculi of size less than 20 mm. Materials and methods We retrospectively analysed data of children who underwent RIRS for either primary or residual renal calculi from January 2017 to January 2021. Children less than 5 years underwent passive ureteric dilatation with stenting preoperatively. A7.5 Fr flexible ureteroscope with an access sheath was used in all cases while performing RIRS. All the patients had a stent left in situ at the end of the procedure. Data including stone burden, number of sittings, operative time, stone-free rate (SFR) and grade of post procedural complications were analysed with appropriate statistical methods. Results A total of 20 patients were included in this study. The median age at presentation was 9 years ranging from 9 months to 18 years. Eight patients (40%) presented with primary renal calculi and underwent RIRS directly while the rest of the 12 (60%) had residual calculi following other procedures like SWL, PCNL before undergoing RIRS. Seven patients (35%) had congenital renal anomalies. The mean stone size and operating time (OR) was 12.6 +/- 3.2 mm 84.5 +/- 7.2 min respectively. The post-procedural complications were seen in 4 (20%) patients in the form of Grade-1 modified Clavein classification in 3 and Grade 2 in 1 patient. The 100% stone-free rate was achieved in 80% of the cases after first attempt. Discussion In the present series, RIRS was effective in both the types of stones (primary and residual) less than 20 mm in size, showing 100% stone free rate with maximum of two attempts. Choosing age based optimised passive ureteric dilation led to injury free access for RIRS. Overall complications remained with in low grades and are comparable to current literature. Limitations of the study include small cohort, retrospective study and the need of three anaesthesia procedures in children under 5 years of age. Conclusion RIRS is safe and effective in children with a renal stone(s) less than 20 mm and it has a high success rate in term of achieving stone free status in both primary and residual calculi.