Patients and methods: Since 1987, we have consecutively used four Dornier lithotripters in our Urology Department: an HM4 (N = 319 cases), MPL 9000X (N = 752), Compact (N = 546), and U/50 (N = 427). Both the HM4 and the MPL 9000X are electrohydraulic machines, whereas the Compact and the U/50 are electromagnetic lithotripters.
Results: Treatment strategies prove to be influenced largely by the available imaging modalities: only fluoroscopy on the HM4, ultrasound and fluoroscopy with a movable C-arm on the MPL 9000X and Compact, and simultaneous integrated fluoroscopy and ultrasound on the U/50. We noted a slight increase in stone free rates with time: 85% with the HM4, 88.8% in the two Compact series, and 88.7% with the U/50. The auxiliary procedure rate (before and after SWL) showed a steady decline, from 27.6% with the HM4 to only 10.8% with the U/50. There also was a slight improvement in the retreatment rates. There was an overall improvement of the Effectiveness Quotient which could be attributed to several factors: machine related (improved imaging with better targeting, smaller focus), patient related (decrease in average stone size), and operator related (better treatment strategies, experience).
Conclusion: Although lithotripters may not have become more powerful, SWL treatments have become more effective.