Modified Flank-free Supine Versus Prone PNL in Pediatric Renal Stones: A Prospective Randomized Comparative Trial

Incidence of pediatric urolithiasis varies from 5%-15% in developing countries to 1%-5% in the developed ones. The 5-year recurrence rate of about55% (range, 38%-70%). Fernstrom and Johansson first introduced percutaneous nephrolithotomy (PNL) in 1976. Since that PNL has become widely used for multiple indications. Pediatric PNL was done in the prone position with more rapid and easy puncture point determination, wider field for renal puncture, free application of multiple accesses, and avoidance of visceral injuries, especially the colon. PNL in the supine position has several advantages as, similar success rate and a shorter operative time than conventional PNL. The Amplatz sheath is oriented downward, maintaining a low pressure in the renal pelvis and reducing the fluid absorption with rapid drainage of the fragmented stones. Furthermore, it's easier for the anesthesiologist to control the airway and reduce the neural and ophthalmologic pressure lesions than the prone position. Desoky et al in 2012 described the flank-free modified supine position (FFMSP) and claimed that this position overcomes the mechanical limitation of ordinary supine position because of ample space for puncture, dilatation, multiple tracts, and maneuverability of the system with the nephoscope. Moreover, the surgeon can comfortably sit during the operation, and X-ray exposure is reduced because puncture and dilatation are quite perpendicular to the body, and the operator's hands are outside the fluoroscopic field. it's better to do supine PNL in case of retro renal colon. as we see the supine position in pediatric is still under research and few trials about it had been done with no clear recommendation, so we will compare PNL in pediatric age group in modified free flank supine position versus prone position.