In vitro gallstone fragmentation by three piezoelectric lithotripters.

Several different piezoelectric lithotripters have been under clinical investigation for gallstones in the USA. Design differences in the different shock wave generators result in different characteristics for the three devices and different peak pressures at the focus of the lithotripters. Using gallstone families, we sought to study fragmentation in the three lithotripters. A total of 56 gallstones from eight gallstone families were studied. Forty-eight stones were fragmented in three lithotripters (16 in each), Diasonics (Therasonic), EDAP (LT01), and Wolf lithotripter (Piezolith 2300), at maximum power and a rate of 2-2.5 Hz. A total of 500 shocks was applied to each stone in each of the three lithotripters. Gallstone composition was determined by infrared spectroscopy on one stone of each family (8 x 1). Initial stone weight and size were similar in all the three groups. All families consisted of cholesterol stones ( greater than 70% cholesterol). The fraction of the initial stone mass reduced to fragments less than or equal to 2 mm was not significantly different in the three lithotripters (Diasonics [n = 16] = 60 +/- 4%, EDAP [n = 16] = 53 +/- 6%, Wolf [n = 16] = 50 +/- 7%; p = 0.068).(ABSTRACT TRUNCATED AT 250 WORDS)