Comparison between Micro-(4.85Fr) and Ultramini-(<15Fr) percutaneous nephrolithotomy for the treatment of 10-20 mm kidney stones in preschool children.

Introduction: The incidence of kidney stones in children has steadily increased in recent years. Miniaturized percutaneous nephrolithotomy (PCNL) techniques, such as micro-PCNL(4.85Fr) and ultramini-PCNL(<15Fr), have become increasingly prevalent in pediatric kidney stone treatment due to their high stone clearance rate and low complication rate. This study aimed to compare the efficacy and safety of micro-PCNL and ultramini-PCNL in preschool children with 10-20 mm kidney stones.

Patients and methods: A retrospective analysis was performed on data from patients under 6 years who received micro-PCNL and ultramini-PCNL surgeries in our hospital between January 2020 and January 2024. The inclusion criteria consisted of pediatric patients (<6 years) with unilateral 10-20 mm kidney stones. Patients with urinary tract malformations or comorbidities were excluded from the study. Patient demographics, stone characteristics, and intra- and postoperative parameters were analyzed.

Results: There were 33 patients in the micro-PCNL group and 31 patients in the ultramini-PCNL group, with a mean age of 3.1 ± 1.3 years and 3.6 ± 1.8 years (p = 0.208), respectively. The stone size was 15 ± 4 mm in the micro-PCNL group and 16 ± 4 mm in the ultramini-PCNL group (p = 0.326). Micro-PCNL and ultramini-PCNL groups showed comparable stone-free rates (84.8 % vs. 87.1 %, p = 0.796) and procedure times (49 ± 17 min vs. 54 ± 23 min, p = 0.218). However, a significantly shorter hospitalization period was observed in the micro-PCNL group compared with the ultramini-PCNL group (2.3 ± 1.3 days vs. 4.6 ± 2.2 days, p < 0.001). Complications were similar between groups, with 12.4 % in the micro-PCNL group and 16.1 % in the ultramini-PCNL group and no severe hematuria was observed.

Conclusions: In preschool children with 10-20 mm kidney stones, both micro-PCNL and ultramini-PCNL achieve similarly high stone-free rates with minimal complications, showing comparable outcomes in appropriately selected patients with experienced surgeons.