Ultra-mini Percutaneous Nephrolithotomy (UM-PCNL) with a Semi-rigid Ureteroscope in Preschool Children: An Innovative Experience in Southern Iran

Purpose: Percutaneous nephrolithotomy (PCNL) has undergone extensive modification to reduce complications. One of the recent advances in minimally invasive procedures is the advent of ultra-mini PCNL (UM-PCNL), which provides miniaturized access to the kidney. However, the specific instruments applied in UM-PCNL may not be found in centers with limited resources. This study evaluated the safety, feasibility, results, and short-term complication rates of performing UM-PCNL using a semi-rigid ureteroscope in preschool children. Materials and Methods: Between September 2013 and September 2021, a total of 68 patients, including 42 boys and 26 girls with a mean age of 3.2 +/- 2.4 years, underwent UM-PCNL with a 4.5French tip ureteroscope instead of an ultra-mini nephroscope in children aged less than 7 years old. The procedure was done under general anesthesia in the prone position. The nephrostomy tract was dilated to 12F. Stones were fragmented using a pneumatic lithotripter. Irrigation was done with normal saline. Results: The early stone-free rate (SFR) was 91%, and the short-term total SFR was 97%. No statistically significant difference was found in pre-operative and post-operative Hb, BUN, Cr, Na+, and K+. Fever (11 patients) and ileus (5 patients) constituted the majority of complications, and only one patient required a blood transfusion. None of the cases undergoing UM-PCNL with this method required a re-do PCNL. Conclusion: Our experience shows that with sufficient experience in handling semi-rigid ureteroscopes, urologists practicing in centers with limited resources could perform UM-PCNL with relatively favorable outcomes.