Accelerated destruction of large, calcified gallstone burdens by performing lithotripsy in the presence of methyl t-butyl ether: an in vitro study.

Numerous, large, or calcified gallstones hinder successful extracorporeal fragmentation. The purpose of this study was to investigate an in vitro method that could accelerate the destruction of these types of gallstone burdens. Matched sets of partially calcified gallstones, each set having a combined stone diameter greater than 3 cm, underwent lithotripsy while immersed in either 15 cc of bile, methyl t-butyl ether (MTBE), or dimethyl sulfoxide (DMSO), with a fourth set serving as a control. Results showed a 20% reduction in the relative weight of all fragments, an eightfold reduction of the relative weight of fragments greater than 3 mm, and a 50% reduction of the number of large fragments when the stones were immersed and shocked in MTBE rather than when shocked in bile. Dimethyl sulfoxide hindered gallstone destruction. These results indicate that large, partially calcified gallstone burdens can be more successfully destroyed if lithotripsy is performed in the presence of a small quantity of MTBE rather than in bile alone or in the presence of DMSO. If proven safe in vivo, this technique could expand the applicability of lithotripsy to those with larger, partially calcified stone burdens.