All procedures were performed under continu¬ous intravenous sedo-analgesia (using a combi-nation of ketamine 1 mg/kg and propofol 0,5-1 mg/kg) with fluoroscopic or ultrasonograpic imaging in a supine position. Shock wave number was limited to a maximum of 3000 waves/session. In the conventional group the voltage was only 13 kV. The stone burden was defined as the stone area that was calculated by multiply¬ing the largest length and width of the individual stones measured from the abdominal plain X-ray.

All procedures were performed under continu¬ous intravenous sedo-analgesia (using a combi-nation of ketamine 1 mg/kg and propofol 0,5-1 mg/kg) with fluoroscopic or ultrasonograpic imaging in a supine position. Shock wave number was limited to a maximum of 3000 waves/session. In the stepwise group, the voltage was started at 10 kV and increased stepwise (every 250 shock waves) to 13 kV. The stone burden was defined as the stone area that was calculated by multiply¬ing the largest length and width of the individual stones measured from the abdominal plain X-ray.

All procedures were performed under continuous intravenous sedo-analgesia (using a combination of ketamine 1 mg/kg and propofol 0,5-1 mg/kg) with fluoroscopic or ultrasonograpic imaging in a supine position. Shock wave lithotrpisy was poerformed with a Dornier Compact Delta lithotripter (Dornier Medtech, Germany). Shock wave number was limited to a maximum of 3000 waves/session. In the conventional group the voltage was only 13 kV. The stone burden was defined as the stone area that was calculated by multiplying the largest length and width of the individual stones measured from the abdominal plain X-ray.

The stone burden was defined as the stone area that was calculated by multiplying the largest length(cm)and width (cm)of the individual stones measured from the abdominal plain X-ray. To detect fragmentation of the stone and necessity of re-treatment a plain film were used during control. Stone clearance was assessed at three months. Stone-free state was defined as the absence of stone fragments on a good quality plain X-ray. Clinical success was considered if the residual fragments were 2-3 mm or less in asymptomatic patients.

To detect obstruction in the system, ultrasonography was used during control.

In case of non-opaque Stones, stone borden was evalusted with spinal computed tomography. Clinical success was considered if the residual fragments were 2-3 mm or less in asymptomatic patients.