en Kidney, Urinary and Genital Surgery (urology) Review <span style="font-size:11pt"><span style="line-height:107%"><span new="" roman="" style="font-family:" times="">Background: Pediatric nephrolithiasis is increasingly recognized and carries a substantial lifetime recurrence burden. Infants and preschool children are uniquely challenging because of small-caliber urinary tracts, limited physiologic reserve, anesthesia exposure, radiation sensitivity, and the possibility of metabolic or genetic disease.</span></span></span><br> <span style="font-size:11pt"><span style="line-height:107%"><span new="" roman="" style="font-family:" times="">Objective: To narratively synthesize clinically relevant evidence guiding treatment selection among shock wave lithotripsy (SWL), flexible ureteroscopy/retrograde intrarenal surgery (fURS/RIRS), and miniaturized percutaneous nephrolithotomy (mini-PCNL) in infants and preschool-aged children.</span></span></span><br> <span style="font-size:11pt"><span style="line-height:107%"><span new="" roman="" style="font-family:" times="">Methods: PubMed/MEDLINE-indexed literature, current European Association of Urology (EAU) guidance, and citation tracking of key pediatric studies were reviewed through September 2026. Evidence was selected for clinical relevance to renal stone management in children, with emphasis on infant- and preschool-specific cohorts, comparative studies, major pediatric series, and evidence syntheses. The review is narrative rather than systematic; study findings were interpreted in context rather than statistically pooled de novo.</span></span></span><br> <span style="font-size:11.0pt"><span style="line-height:107%"><span new="" roman="" style="font-family:" times="">Results: SWL remains the least invasive intervention and is suitable for many small, targetable renal stones, but retreatment can increase cumulative anesthesia burden. fURS/RIRS provides active clearance without renal puncture and is useful for SWL-unfavorable stones, although small ureteral caliber may necessitate prestenting or staged access. Mini-PCNL offers efficient clearance of larger or complex burdens but carries greater tract-related bleeding and access concerns. Preschool-specific comparisons show that differences in single-session stone-free rate may narrow after auxiliary procedures, making cumulative procedural burden a key treatment endpoint</span></span></span> pediatric urolithiasis, infant nephrolithiasis, preschool children, shock wave lithotripsy, flexible ureteroscopy, retrograde intrarenal surgery, mini-PCNL, stone-free rate. 45 60 http://tbsrj.mazums.ac.ir/browse.php?a_code=A-10-3548-8&slc_lang=en&sid=1 Mahdi Younesi Rostami dr.mehdiyounesi@gmail.com 100319475328460032197 100319475328460032197 No Associate Professor of Endourology, Department of Urology, School of Medicine, Sari Imam Khomeini Hospital, Mazandaran University of Medical Sciences Javid Gholami Dr.javid79@gmail.com 100319475328460032198 100319475328460032198 Yes Assistant Professor of Urology, Mazandaran University of Medical Sciences Erfan Rohaninia rohaniniaerfan81@gmail.com 100319475328460032199 100319475328460032199 No Medical Student, Department of Medicine, Mazandaran University of Medical Sciences, Sari, Iran