Super-Mini Percutaneous Nephrolithotomy in the Treatment of Pediatric Nephrolithiasis: Evaluation of the Initial Results

To evaluate the efficacy and safety of super-mini percutaneous nephrolithotomy (SMP) in the treatment of pediatric kidney stones.We reviewed the records of 111 children with renal stones treated with SMP technique in four different centers between September 2014 and September 2015. The indications for SMP treatment in all these kids were either previously failed shock wave lithotripsy or retrograde intrarenal surgery approaches, according to their parents' preferences. Nephrostomy tracts used in the SMP system ranged from 10F to 14F in size. Lithotripsy was performed using either a Holmium laser or pneumatic lithotripter. Perioperative and postoperative parameters along with operative data were recorded in detail and stone components were analyzed by infrared spectroscopy.This study included 71 boys and 40 girls with a mean age of 3.90 ± 3.53 years (range 0.5-15). The mean stone burden was 1.4 ± 0.6 cm (range 0.8-4.8). Mean operative time was 39.4 ± 26.2 minutes (range 7-105). The mean hemoglobin drop was 10.2 ± 7.1 g/L (range 0-25) and no transfusion was needed. Significant complications were observed in 17 (15.3%) children with 10 and 7 cases in Clavien grade I and grade II, respectively. Complete stone clearance on postoperative day 1 and on 3-month follow-up was 84.7% (94/111) and 90.1% (100/111), respectively. Ninety-five (85.6%) children did not require any type of catheters (total tubeless). The mean hospital stay was 2.7 ± 1.5 days (range 1-7).Our preliminary data demonstrated that SMP was safe and effective. SMP could be a feasible treatment option for pediatric stone disease. Further randomized controlled trials are still needed to prove the efficacy of using the SMP system in children, particularly in those with larger stones.