EFFECT OF LASER FRAGMENTATION OF CHOLESTEROL AND MIXED GALLSTONES ON INVITRO DISSOLUTION IN METHYL TERT-BUTYL ETHER

This study examined cholesterol and mixed gallstone dissolution in vitro by methyltert-butyl ether (MTBE) after gallstone fragmentation. Three morphologically identical gallstones were obtained from 42 patients. One stone from each patient was fragmented with laser energy at a wavelength of 504 nm delivered to the stone surface with a 320-μm quartz fiber. Intact and fragmented stones from the same patient were incubated without stirring in MTBE and dissolution was expressed as the percent of initial stone weight remaining after 2 hr. Stone composition did not correlate with the amount of laser energy required for stone fragmentation. Fragmented stones dissolved faster than intact stones in MTBE with 13.97%±0.37% vs 31.0%±0.51% respectively (mean±SEM) of initial stone weight remaining at 2 hr (P<0.0001). Initial stone weight and stone matrix content significantly predicted dissolution of intact (P=0.0033 and P=0.0483, respectively) and fragmented stones (P=0.003 and P=0.0001, respectively) in MTBE. These data suggest that the gallstone matrix may inhibit stone dissolution even after stone fragmentation. © 1990 Plenum Publishing Corporation.