Second generation extracorporeal shock wave lithotripsy for treatment of urolithiasis.

We have undertaken extracorporeal shock wave lithotripsy (ESWL) using the second generation lithotripter, Sonolith 2000. Shock waves are generated by an underwater spark gap discharge and stone localization is performed using an ultrasound scanner. A total of 49 treatments were given to 39 patients with upper urinary tract calculi. Twenty one patients (56.8%, 21/37) were completely free of stones and seven patients (18.9%, 7/37) had residual sandy particles on the 42nd day after ESWL. Seven patients (18.9%, 7/37) had residual fragments less 5 mm in diameter and two patients (5.4%, 2/37) had residual fragments exceeding 6 mm in diameter six weeks after ESWL. Two patients were lost to follow-up. There was a strong correlation between the stone free rate and stone size. Almost all stone of more than 25-30 mm in diameter required more than one session. There were no severe complications during and after ESWL.