In vitro comparison of shock wave lithotripsy machines.

PURPOSE: We tested the hypothesis that shock wave lithotripsy machines vary in the ability to fragment stones to small size. MATERIALS AND METHODS: Calcium oxalate monohydrate, calcium hydrogen phosphate dihydrate, cystine and magnesium ammonium phosphate hexahydrate calculi were fragmented in vitro with the 22 kV. Dornier HM3, section sign 20 kV. Storz Modulith SLX, parallel, 15.6 kV. Siemens Lithostar C, paragraph sign 24 kV. Medstone STS-T,** 26 kV. HealthTronics LithoTron 160,daggerdagger 20 kV. Dornier Doli section sign and 22.5 kV. Medispec Econolithdouble daggerdouble dagger lithotriptors. Stones were given 500 or 2,000 shocks, or the Food and Drug Administration limit. Post-lithotripsy fragment size was characterized using sequential sieves and compared. RESULTS: Stone mass was statistically similar in the cohorts (p >0.94). Fragment size decreased as the number of shocks increased when the machine and stone composition were constant. Magnesium ammonium phosphate hexahydrate calculi were completely fragmented by all devices. At Food and Drug Administration treatment limits the mean incidence per device of calcium hydrogen phosphate dihydrate, calcium oxalate monohydrate, cystine and magnesium ammonium phosphate hexahydrate stones rendered into fragments greater than 2 mm. was 0% for the HM3, Modulith SLX and Lithostar C, 10% for the STS-T, 3% for the LithoTron 160, 29% for the Doli and 18% for the Econolith (p = 0. 04); 0% for the HM3, Modulith SLX, Lithostar C, STS-T and LithoTron 160, 4% for the Doli and 9% for the Econolith (p = 0.15); 1% for the HM3, 0% for the Modulith SLX, 1% for the Lithostar C, 10% for the STS-T, 14% for the LithoTron 160, 3% for the Doli and 9% for the Econolith (p = 0.44); and 1% for the HM3, 0% for the Modulith SLX, 1% for the Lithostar C, 10% for the STS-T, 14% for the LithoTron 160, 3% for the Doli and 9% for the Econolith (p = 0.44), respectively. CONCLUSIONS: Shock wave lithotriptors vary in fragmentation ability. The HM3, Modulith SLX and Lithostar C machines yield smaller fragments than other machines.

Use of intravenous contrast material during in situ extracorporeal shock wave lithotripsy of ureteral calculi.

PURPOSE: We prospectively studied the usefulness of contrast material to facilitate extracorporeal shock wave lithotripsy (ESWL) of ureteral calculi in situ. MATERIALS AND METHODS: Followup was available for 67 consecutive patients with ureteral calculi treated in situ (without ureteral catheterization) on an unmodified Dornier HM-3 lithotriptor. In 30 patients radiographic contrast material was administered to facilitate targeting of calculi. Intraoperative obstruction was determined by the lack of passage of contrast material beyond the calculus during treatment. Immediate postoperative obstruction was defined as prolonged retention of contrast material on a postoperative radiograph. RESULTS: Passage of contrast material beyond the calculus was not noted in 9 of 26 evaluable patients, 5 of whom appeared to have obstruction on postoperative radiography. Of these 5 patients 3 required immediate hospitalization for pain control, compared to none of those without intraoperative obstruction. The stone-free rates after ESWL, including success following adjunctive measures or repeat ESWL, were 83, 100 and 87% for calculi in the proximal, middle and distal ureter, respectively. Neither use of contrast material, nor intraoperative or postoperative obstruction altered the eventual success of ESWL. CONCLUSIONS: The administration of intravenous contrast material during ESWL allows for effective treatment of ureteral calculi that otherwise could not be imaged adequately without ureteral catheterization, and provides information valuable for short-term prognosis.