[Initial experience using a new type extracorporeal lithotripter with an anti-miss-shot control device]

The results of clinical trial using a TOSHIBA piezolectric extracorporeal lithotripter are presented. The advantages of this machine are the installation of an anti-miss-shot control device (AMCD) to prevent miss-shots to the renal tissue and the improved ultrasound stone localization by an over-head type applicator. AMCD functions so that shock waves are generated only when the stone is in the focal region. Forty patients with urinary tract stone were treated by this machine from October 1989 to March 1990 at the Department of Urology, Tohoku University School of Medicine. Almost all patients could be treated with an analgesic only. The X-ray film obtained three months after ESWL treatment showed that 23 cases (57.5%) were stone-free and 10 cases (25.0%) had stone fragments of less than 4 mm. The successful rate of ESWL using this machine was 82.5%, the result was better than that using other piezolectric machines. No serious complication was observed, except mild hematuria in all cases. Milder postoperative hematuria suggested the decrease of renal tissue injury. It is concluded that the treatment with this machine is safe and seems to be more favorable than the conventional ones.