To evaluate the safety and efficacy of pediatric percutaneous nephrolithotomy (PCNL) in the flank-free modified supine position (FFMSP). PCNL in the supine position is increasingly and successfully used in pediatric age group. Different modifications of supine positions have been described; however, the best supine position is not well established and remains a matter of debate.

This prospective study included 22 children presenting with single renal pelvis stone (2-3 cm) in the period between May 2012 and April 2014. Diagnosis was set by plain x-ray and computed tomography in all patients. PCNL was performed with the patients placed in the FFMSP. The operative time and hospital stay were estimated. The outcome and any perioperative complications or conflicts were recorded.

The study included 22 children (15 boys and 7 girls) with a solitary renal pelvis stone. Mean ± standard deviation age of the patients was 9.5 ± 3.2 years (range, 3-15.5 years). Stone length, operative time, and hospital stay had mean ± standard deviation of 2.4 ± 0.23 cm, 65.1 ± 18.7 minutes, and 4.4 ± 0.9 days. Stone-free rate was 90.9% after 1 session of PCNL. One patient (4.5%) needed a second-look PCNL. Shock wave lithotripsy was performed for another patient. Postoperative fever occurred in 4 patients (18.2%). One patient received postoperative blood transfusion. Postoperative transient urinoma occurred in 2 patients (9.1%).

PCNL in pediatric age group via FFMSP was proved to be safe and effective in management of renal pelvis stones of size 2-3 cm. It provides stone clearance rate comparable with that reported of conventional PCNL in the prone position.