Piezoelectric extracorporeal shock wave lithotripsy in children.

Piezoelectric lithotriptors have by far the smallest focal zone of all lithotriptors. By pinpointing this high pressure zone onto the stone with continuous visualization by ultrasonography throughout treatment, the volume of the kidney exposed to potentially harmful pressures is minimized and radiation hazards are avoided. We treated in this manner 33 renal and 8 ureteral stones in 25 renoureteral units of 22 children 4 months to 14 years old. No child required any other type of primary stone treatment during this period. Piezoelectric lithotripsy is painless and anesthesia was needed in only 11 children too young to cooperate. With a retreatment rate of 40 per cent, all stones were fragmented completely. After treatment only 48 per cent of the children had transient hematuria, which always subsided within 24 hours. Of the children 14 per cent required analgesics and 5 per cent had fever in the postoperative period. One child needed temporary nephrostomy drainage. Otherwise, the passage of stone debris was remarkably smooth and after 3 months 96 per cent of the renoureteral units were free of calculi. Evidence of soft tissue damage, such as skin ecchymosis, perirenal hematoma or retardation of renal growth, was not observed.