Semi-closed-circuit vacuum-assisted mini percutaneous nephrolithotomy in the pediatric population: the initial experience of two tertiary referral centers

Background: Percutaneous nephrolithotomy (PCNL) is the gold-standard for complex renal stones treatment in the pediatric population. While the miniaturization of PCNL reduces the risk of bleeding, it can hinder surgical and functional outcomes. The aim of the study is to assess the safety and feasibility of semiclosed-circuit vacuum-assisted Mini-PCNL (vmPCNL) in pediatric patients. Methods: From January 2017 to December 2018, we prospectively collected data on consecutive vmPCNLs from two European tertiary referral centers. The procedure was performed with the ClearPetra® access sheath equipped with a lateral arm connected to the aspiration system (pressure setting ~ 120-150 cmH2O) by a 200 ml plastic stone collector. Pre-, intra- and post-operative data and costs were analyzed. The stone-free rate (SFR) was defined as absence of residual fragments > 4 mm with either ultrasound or kidney, ureter, and bladder x-ray. Results: Eighteen vmPCNLs were performed in 16 renal units of 13 children. The median age was 119 months (IQR: 97-160) and the weight was 29 Kg (IQR: 25-40). The median cumulative stone size was 32 mm (22-46) with 8 (44.4%) cases of staghorn stones. The OT was 128 min (IQR: 99-167). The basketing was unnecessary in 6/18 (33%) cases. Neither intra-operative complications nor blood transfusions occurred. Post-operative fever was observed in 5/18 (27.8%) cases; in one case a double J ureteral stent was placed for concomitant hydronephrosis. The SFR was 81.3% (13/16), rising to 93.8% (15/16) after ancillary procedures. The materials costs of a vmPCNL (734.8 €) were comparable to mini-PCNL using a reusable set (710.7 €). Conclusions: The vmPCNL seems to be sustainable, safe and feasible for kidney stones treatment in the pediatric population.