Modulith SL20--development and clinical experience.

A third generation lithotripter was developed incorporating the advantages of high disintegrative efficacy, anaesthesia-free treatment, combined sonographic and fluoroscopic localization system as well as a multifunctional table for interdisciplinary use. The shock wave generator consists of a cylindrical-shaped electromagnetic coil with a paraboloid reflector. The waves are coupled by means of a water cushion and an impedance adapted foil in which the patient is comfortably positioned. Stones are localized by an in-line ultrasound probe or fluoroscopically by the integrated C-arm. Preclinical trials using the in-vitro stone model demonstrated the superior disintegrative capacity. The in-vivo animal studies evaluated the dose-dependent and reversible kidney trauma, which was comparable to that induced by other lithotripters. The clinical evaluation of the Modulith SL since 1988 was divided into three phases with different technical equipment. It was indicated that sonographic stone localization enables treatment of nearly all kidney stones and 12% of the ureteric calculi. As preference was given to in situ disintegration of all ureteral stones, X-ray targeting became necessary. By increasing the generator voltage in the third phase together with advanced experience, the disintegration rate (94%) was improved. The number of auxiliary measures after ESWL (11%) and treatment time (average 39 min) was decreased. Eighty-eight percent of our patients were stone-free at follow-up. The experience demonstrated that this lithotripter is also easy to handle for gallbladder stones and highly effective (82%) in treatment of endoscopically non-extractable bile duct stones.