Ultrasound-Only-Guided vs Fluoroscopy-Guided Mini-Percutaneous Nephrolithotomy in Children: A Randomized Comparative Trial.

Background and objective: Avoidance of ionizing radiation during management of pediatric urolithiasis is imperative. Objectives are to evaluate feasibility of ultrasound-only-guided mini-percutaneous nephrolithotomy (PNL) in children and to compare it with fluoroscopic guidance. Methods: Randomized comparative trial (NCT03250559) including 60 renal units with stones >1 cm in 57 children ≤14 years. Exclusion criteria were anomalous kidney and Guy's stone score IV. Mini-PNL was either ultrasound or fluoroscopy guided (30 cases each). The two groups were compared regarding operative details and postoperative outcomes. Stone clearance was evaluated by computed tomography 2 weeks postoperatively and on last follow-up. Follow-up period ranged 1.17-3.42 years. Results: In ultrasound group, fluoroscopy was needed in one case during access and in three cases for detection of residuals. In fluoroscopy group, ultrasound was needed in two cases to manage fluid collection. Fluoroscopy group had significantly fewer dilated tracts (p = 0.021), fewer supra-costal tracts (p = 0.002), lower calyceal approach (p < 0.001), more nephrostomy tubes (p = 0.008), and shorter hospital stay (p = 0.010). The two groups were comparable regarding other operative details, stone clearance and complications. On last follow-up, stone-free rate was 86.2% in ultrasound group and 93.3% in fluoroscopy group. After exclusion of Guy's III cases, these rates increased to 96% and 96.6%, respectively. Conclusions: Ultrasound-only-guided mini-PNL in children is feasible. In comparison with fluoroscopic guidance, it leads to more dilated tracts, higher calyceal approaches, less nephrostomy tubes, and longer hospital stay. However, it yields comparable outcomes regarding access time, complications, and stone clearance, especially for Guy's I/II cases.