Consecutive experience with four Dornier lithotripters: HM4, MPL 9000, compact, and U/50

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.

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).

Although lithotripters may not have become more powerful, SWL treatments have become more effective.