Extracorporeal shock wave lithotripsy of radiolucent urinary calculi using the Siemens Lithostar Plus

Between October 1989 and June 1991, 1,250 patients with urinary calculi were treated at our institution using the Siemens Lithostar. A total of 17 patients (1.37%) with radiolucent or slightly opaque calculi underwent lithotripsy with the Lithostar Plus, which has an overhead electromagnetic generator module and a localization system composed of a real-time on-line 3.5 mHz. ultrasound transducer. The stones were located in the calices in 52.9% of the cases, renal pelvis in 17.7%, ureter in 23.5% and bladder in 5.9%. Followup consisted of a nephrotomogram or ultrasound 1 day and 1 to 3 months postoperatively. Complete removal of all stone fragments was achieved in 76.4% of the cases after 3 months. Retreatment was necessary in 23.5% of the cases. All treatments were performed without anesthesia and hospitalization. Complications were present in 11.8%; perirenal hematoma was noted in 1 patient but this resolved spontaneously within a few days and the same occurred in 1 patient with renal pain. Extracorporeal shock wave lithotripsy using the Lithostar Plus proved to be an effective noninvasive procedure to treat radiolucent and slightly opaque urinary calculi. However, since the Lithostar Plus has a higher power setting, care must be taken to avoid damage with the use of high energy.