Tackling complex kidney stones in children: the role of vacuum-assisted mini-PCNL - a single-center study

Objective To evaluate the efficacy and safety of semi-closed-circuit vacuum-assisted Mini-PCNL (vamPCNL) in the management of complex kidney stones in pediatric patients. Methods We conducted a prospective, single-arm, single-center cohort study. All vamPCNL procedures performed from December 2017 to March 2025 for minimally invasive management of kidney stones in our tertiary referral center were included in this study. The procedure was performed with the ClearPetra® (Well Lead Medical Co., Ltd., Guangzhou, China) disposable suction nephrostomic access sheath. Preoperative, intraoperative, and postoperative data were prospectively collected, analyzed, and reported in detail. The stone-free rate (SFR) was defined as the absence of residual fragments with either ultrasound, X-ray, or CT scan. Postoperative complications were graded according to the modified Clavien-Dindo classification for PCNL. Results A total of 67 procedures were performed. Median age was 10 years (Interquartile range [IQR] 6–14 years), median stone volume was 1.8 cm3 (IQR: 0.9–3.3 cm3). A preexisting metabolic pathology was present in 44.7% of the population. In this setting, most of the patients (80.6%) harbored high-burden stones (either staghorn or multiple locations stones). While no intraoperative complications were observed, 12 (17.9%) postoperative complications occurred: 8 consisting of urinary tract infections, managed with antibiotic therapy (Clavien 2); 3 urinary extravasation managed conservatively (Clavien 1) and 1 ureteral obstruction due to a migrated stone fragment which required the placement of a double J stent (Clavien 3a). No patient required blood transfusions. SFR varied from 84.6% in single locations stones, 63% in staghorn stones, to 57% in multiple-locations stones. When the overall stone volume exceeded 1.7cm3, there was a statistically significant drop in the stone free rate (50% vs. 80%, p = 0.023). Similarly, the stone free rate was significantly lower when the overall stone number was > = 3 compared to < 3 (SFR 40% vs. 83.9%, respectively, p = 0.002). Conclusion vamPCNL is an effective and safe treatment for large and complex kidney stones in pediatric patients. The technique is associated with good SFRs, low intra- and postoperative complication rates, particularly with regards to bleeding, and offers a minimally invasive solution even for clinically challenging pediatric cases.