In the United States the incidence of nephrolithiasis in children is increasing. Studies from several different regions of the United States have demonstrated an increase in the number of clinic and emergency room visits along with hospitalizations due to nephrolithiasis. The incidence is higher in warm climates and in areas with immigrants from countries with endemic stone disease. Boys and girls appear to be equally affected. Currently 75% to 80% of pediatric patients have upper tract stones. Metabolic disorders are responsible for 50% of stones in children. Up to 22% of children with nephrolithiasis will require surgical intervention within 6 months of presentation. Of these patients, 25% will require more than one procedure.

Multiple factors must be considered when planning pediatric stone surgery. Patient age and size often require special instruments. Stone size and location may limit access to the stone. Stone composition is also important. Knowledge of anatomic abnormalities such as calyceal diverticula, ureteroceles, or ureteropelvic junction obstruction is important as well. Prior urologic surgery such as ureteral reimplantation may limit surgical options. Shock wave lithotripsy and ureteroscopy are used for smaller renal and ureteral stones with similar stone-free rates. Larger renal stones require percutaneous nephrolithotomy, alone or in combination with shock wave lithotripsy or ureteroscopy. Open or laparoscopic surgery is rarely necessary.

The initial management of children presenting acutely with symptoms of stone disease is no different than that of adults. Children should receive ample pain medications, antiemetics, and hydration as needed. Infection should be treated with antibiotics and when present, concomitant obstruction should be relieved quickly with either ureteral stent placement or percutaneous nephrostomy. Off-label use of alpha-1 blockers as medical expulsive therapy may be beneficial in children with ureteral stones. In all cases, renal imaging guides treatment (Fig. 21-1). In afebrile children with a stone less than 4 mm in size and no associated anatomic abnormalities, observation is appropriate. Failure of an observed stone to pass, uncontrolled pain, or intractable nausea and vomiting, even in the presence of a relatively small stone, are indications for intervention.

A. Shock Wave Lithotripsy

Shock wave lithotripsy is a noninvasive method of stone fragmentation (Fig. 21-2). Children have decreased shock wave attenuation because of
their small size, which limits trauma to surrounding organs. Long-term studies indicate that after extracorporeal shock wave lithotripsy (SWL) children do not develop renal scarring. Renal function and linear growth do not appear to be affected and no increased risk of hypertension or other medical renal disease have been documented.