الفهرس 
ETIOLOGYOnly 14 pages are availabe for public view
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Abstract
T
he incidence of urolithiasis in children has increased globally over the last few decades. The pattern of stone disease has also changed, with an increase in kidney stones secondary to calcium oxalate or calcium phosphate in the kidneys and a decrease in bladder stones composed of ammonium and urate. Evidence favors a significant role of dietary practices in the increase in pediatric urolithiasis. Local climatic conditions play an important role in the stone pathogenesis. Stone occurrence increases in warmer and sunnier regions. The individual risk of stone disease is modified by familial predisposition and genetic susceptibility. Metabolic workup is indicated in all children with a stone disease. Adequate water intake and maintaining a balanced diet are important to reduce the risk of kidney stones. At-risk subjects identified by metabolic workup can benefit by an intervention directed to the specific defect.
Despite the increased sensitivity of CT compared to ultrasound, concerns regarding radiation exposure limit its use in young children. Although unpredictable, risk as high as 1 fatal cancer for every 1,000 CTs performed in young children has been reported. Balancing the risks of radiation exposure for post treatment stone detection and the risks of anesthesia for secondary procedures is a challenging dilemma for contemporary pediatric endourologists. Newer, high-speed helical CT scanners reduce radiation exposure and rarely require intravenous sedation. In addition, maximizing intraoperative fragment detection by direct visualization in URS and PCNL and continued development of high resolution real-time fluoroscopy may result in less reliance on postoperative imaging and decrease the need for second look nephroscopy/URS, SWL or sandwich therapy.
Pediatric urolithiasis poses a technical challenge to the urologist. Aims of the management should be complete clearance of stones, preservation of renal function and prevention of recurrence. Despite the consensus of SWL being the initial treatment of choice for most stones in pediatric patients, there are certain indications for other modalities as well. With improvement in instrumentation and technology, endoscopic management has become safe and effective. Percutaneous nephrolithotomy and SWL are safe and efficacious in managing pediatric stones of 1-2cm. Indications for PCNL in children are large stone burden, significant renal obstruction and renal infection. Miniperc has clearly established its superiority over standard PCNL for management of small bulk as well as large bulk complex renal calculi. Multiple-tract miniperc has a big advantage as it can achieve this goal without adding muchto the complication rate and maintaining the high safety profile. Although RIRS is a modality to treat small renal stones, miniperc may score because of less operative time. Thus, miniperc has now established its role in managing renal stone.
Ureteroscopy provides efficient stone clearance in mid and lower ureteric stones. Transurethral cystolithotripsy is generally avoided in pediatric patients, but is feasible in single vesical stone less than 1cm. Percutaneous cystolithotomy or open cystolithotomy is generally the alternative for pediatric vesical stones.
With no prospective randomized evidence currently available, individual surgeon experience is the most important determining factor in counseling patients regarding the most effective primary treatment option. Similar to endourological management in the adult population, familiarity with the full spectrum of endourological techniques facilitates a minimally invasive approach to the entire pediatric urinary tract.
Early experiences demonstrate that laparoscopic pyelolithotomy is feasible, safe and efficacious as an alternative to open pyelolithotomy in children, and needs further study. However, due to the demanding technical nature these procedures will likely be limited to the treatment of endourological management failures at academic centers with abundant expertise in laparoscopic and robotic pediatric surgery.
After definitive therapy, children are followed in a multidisciplinary stone clinic including urological, renal, nutrition and endocrine evaluation if necessary. Routine evaluation includes urine culture, 24-hour urine collection and office based ultrasound or abdominal films to detect recurrence. Until the risks of radiation exposure in children are more clearly defined, surveillance in these children will be individualized based on age, anatomy, stone burden and underlying metabolic abnormalities.
As the surgical management of pediatric stone disease evolves, the lack of a consistent definition of stone-free after definitive therapy is an issue that remains unaddressed. Although controversial, in select adult patients all stone fragments can be considered clinically significant and can lead to stone recurrence.