The Role of Renal Parenchymal Thickness and Tract Length on Mini-Percutaneous Nephrolithotomy Outcomes in Pediatric Patients

Purpose: To evaluate the effects of renal parenchymal thickness (RPT) and tract length (TL) on the stone-free rate (SFR) and complications in pediatric patients who underwent minimally invasive percutaneous nephrolithotomy (mini-PCNL). Materials and Methods: The data of pediatric age group (<18 years) patients who underwent mini-PCNL between 2017 and 2025 in our clinic, which is a tertiary referral center, were retrieved. Eighty patients were included in this study. SFR was determined using low-dose nonenhanced CT in all patients 1 month after procedure. Stone-free status was defined as the complete absence of stones, and the presence of any stone fragment, regardless of size, was defined as residual stone. Results: The mean stone diameter was 22.8 mm, and the mean stone burden was 402 mm 2 . Although 46.3% of the stones were located only in the renal pelvis, 32.5% were staghorn. Mean RPT was 13.6 ± 5.0 mm, TL was 33.0 ± 10.5 mm, and RPT/TL ratio was 0.42 ± 0.13. Complications occurred in 27.5% of the patients. No major (grade 4–5) complications were observed in any patient. After mini-PCNL, stone-free status was achieved in 65% of patients. The mean diameter of residual stone was 3.4 ± 5.9 mm. When comparing patients who were stone free and those with residual stones, RPT ( p = 0.059), TL ( p = 0.315), and RPT/TL ratio ( p = 0.563) were similar between groups. When patients with and without complications were compared, no statistically significant difference was found between the two groups in RPT ( p = 0.084), TL ( p = 0.589), and RPT/TL ratio ( p = 0.723). Conclusions: Mini-PCNL appears to be an effective and safe surgical technique that can be applied in pediatric patients with kidney stones, regardless of RPT and TL; however, prospective multicenter studies are necessary to confirm our results in a larger number of patients.