The clinical introduction of a third generation lithotriptor: Modulith SL 20.

The Modulith SL 20* was designed as a third generation lithotriptor with outstanding disintegrative efficacy in vitro, and equipped with a combined fluoroscopic and ultrasound localization system integrated in a multifunctional table. Its introduction to clinical extracorporeal shock wave lithotripsy took place in 3 phases. In phase 1 (49 patients) only in line ultrasound localization was possible. The many caliceal stones were adequately disintegrated with restricted generator voltage. In phase 2 (81 patients) fluoroscopic localization with the virtual focus of an adapted x-ray C-arm unit enabled in situ lithotripsy of ureteral stones in 33% of all patients. Phase 3 (549 patients) was characterized by additionally increasing the generator voltage to 20 kv. This development of the lithotriptor by improving the localization system and shock wave energy resulted in the possibility for successful disintegration of stones in the entire upper urinary tract (including the complete ureter), decreased treatment time (52 to 39 minutes) and an improved efficiency quotient (0.45 to 0.67). During phase 3 auxiliary measures were performed before lithotripsy in 24% of the cases. After 1.8% of the treatments minor or moderate perirenal fluid collection or bleeding was detected by routine followup sonography. A 91% stone-free rate was achieved with only 9.3% curative auxiliary measures after extracorporeal shock wave lithotripsy, including a 23% retreatment rate. Thus, the Modulith device had a high efficacy quotient compared with other lithotriptors.