Mini-Percutaneous Nephrolithotomy in Infants with Renal Stones: An Age-Stratified Retrospective Cohort Study

Background: The management of renal stone disease in infants poses unique challenges due to anatomical and physiological differences compared with older children. This study aimed to evaluate the safety and efficacy of mini-percutaneous nephrolithotomy (PCNL) in infants aged ≤1 year and to contextually compare these outcomes with those of an older pediatric reference cohort undergoing mini-PCNL. We hypothesized that, with appropriate miniaturization and patient selection, outcomes in infants would not be inferior to those observed in older pediatric patients. Methods: This single-center, retrospective, age-stratified cohort study included pediatric patients who underwent mini-PCNL for renal stones between January 2016 and September 2025. Patients were divided into two groups: infants (≤1 year) and non-infant pediatric patients aged 1–5 years. Mini-PCNL was defined as surgery performed using a 14-Fr access sheath. The primary endpoint was final stone-free status. Secondary endpoints included initial stone-free status, operative time, hemoglobin decrease, length of hospital stay, transfusion requirement, need for auxiliary procedures, and postoperative complications. Continuous variables were compared using the Mann–Whitney U test, and categorical variables were analyzed using the chi-square or Fisher’s exact test. Results: A total of 85 pediatric patients were included in the study, comprising 31 infants (36%) and 54 non-infant patients (64%). The median stone burden was numerically higher in non-infant patients compared with infants [250 (175–400) vs. 215 (175–265) mm2]; however, this difference was not statistically significant (p = 0.11). Operative time, hemoglobin decrease, and length of hospital stay were comparable between the groups. Initial stone-free rates were 83% in infants and 80% in non-infant patients (p = 0.47), while final stone-free rates reached 90% and 89%, respectively (p = 0.33). Overall complication rates were similar between infants and non-infant patients (17% vs. 19%), and most complications were classified as low-grade. Conclusion: Mini-PCNL can be performed safely and effectively in selected infants aged ≤1 year, achieving stone-free and complication rates comparable to those observed in children aged 1–5 years treated with the same 14-Fr Mini-PCNL technique. These findings suggest that, with appropriate patient selection, miniaturized access, and experienced surgical teams, mini-PCNL is a feasible treatment option for infantile nephrolithiasis. However, multicenter prospective studies with longer follow-up are needed to confirm these results and to evaluate stone recurrence and renal function outcomes better.