Extracorporeal shock wave lithotripsy (SWL) was first described for pediatric nephrolithiasis in 1986; SWL has been a mainstay of treatment for both renal and ureteral calculi in children . SWL is currently regarded as first-line therapy for most renal and upper ureteral calculi <2.0 cm according to the EAU/ESPU guidelines . Meanwhile, the American Urological Association (AUA) considers SWL to be a first-line option along with URS for renal or ureteral calculi <2.0 cm, and a first-line option along with PNL for renal calculi >2.0 cm . The shock waves are better transmitted and spontaneous clearance of fragmented stones in pediatric kidneys is higher than adults' kidneys; thus, SWL treatment seems likely to be more successful in the pediatric population compared to the adult population .Younger age is associated with better stone clearance in children treated with SWL, and this is related mostly to increased ureteral compliance (shorter, more elastic and distensible) and shorter skin-to-stone distance .

Inclusion Criteria:

• Age: 1 year - 5 years old. ( as children younger than 5 years old has shorter skin to stone distance & the option of endoscopic treatment of stones has is not feasible in this age group) Stone size: more than 2 cm & less than 3.5 cm. Stone location: renal pelvis & other calyces.

Exclusion Criteria:

• Age: less than 1 year & more than 5 years old. Stone size: less than 2 cm & more than 3.5 cm. Raised serum creatinine , coagulopathy. Distal urinary tract obstruction. Pulmonary or cardiac disease Anatomical abnormalities (UPJO, horses shoe kidney, ...)