الفهرس 
GENERAL ANATOMYOnly 14 pages are availabe for public view
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Abstract
The first report of PCNL in children was published in 1985. Acceptance of the procedure, for treatment of renal calculi in pediatric patients was delayed because the authors used adult instruments and there was great concern about the deleterious effects of these large instruments on small pediatric kidneys. Then, development of new instruments, technical improvement and presence of endourologist with considerable experience in percutaneous surgery allowed widespread acceptance of PCNL for treating renal calculi in children.
The current indications of PCNL in pediatric patients included large, complex, staghorn stones and those who are contraindicated to undergo SWL or failed SWL treatment. Preoperative radiological investigation of choice was NCCT using low dose protocols to reduce radiation exposure. Antibiotic prophylaxis is recommended by all major urological society guidelines and the procedure must be performed by an experienced team including endourologist, anesthiologist, nurses and technicians. An adequate operative room preparation and armamentarium of machines, scopes and instruments must be available.
Percutaneous renal access is recommended to start at the posterior axillary line and enter the kidney through the top of a posterior calyx. There are many techniques and instruments used for dilatation and the size of the tract is also variable, the one-shot technique ”The Pathway Access Sheath (PAS)” allows for simultaneous balloon tract dilation and percutaneous access sheath placement in one simple step with less fluoroscopy time and equal safety and efficacy. Intra-renal manipulations and lithotripsy should be performed in intelligent and delicate movements to achieve maximum stone clearance without high morbidity. Post-operative care and medications are as important as the operative steps. However, image evaluation of the success varies among reported series. The essential thing is to balance between high radiological exposure for the child and the value of information necessary for determination of stone-free status. Therefore, post-operative radiological investigations must be individualized for each case.
Complications of PCNL include postoperative fever (30%) and bleeding. Bleeding is the most reported complication associated with PCNL and blood transfusion rates ranging from 0% to 23.9 %. To reduce the complications of traditional PCNL and its significant morbidity, Jack man et al. introduced the Mini-PCNL technique using an instrument with 12-Fr rigid nephroscope and 15-Fr sheath in 2001 compared with the 24- to 34-F sized instruments. Then, Desai and his colleagues described the Ultraminiperc (UMP) technique where the tract dilation is 11 F and stone retrieval does not involve expensive disposables such as baskets and graspers. With the recent advances in technology and development of miniature endourological instruments, Single step of PCNL without dilatation could be achieved through the Microperc in which renal access and PCNL are performed using the all-seeing needle with a 4.85Fr tract size.
The reported stone-free rates of PCNL for children in recent large series are satisfactory and ranged from 59 % to 97.2%. In complex stone burden, adjuvant ESWL and ureteroscopy was used to improve the results. The range of complication rates is very wide (1.2% - 60%). This may be attributed to the differences in inclusion criteria, operative techniques, reporting and classification of complications. Among these complications, fever was the most common and bleeding was the most dangerous.
Safety of PCNL in pediatric patients was proved because most of the complications were of minor grades and could be treated conservatively with only 5% incidence of conversion to open surgery. Furthermore, functional evaluation of renal function post PCNL using radio-isotope scanning showed no or minimal deleterious effects.