Experimental gallstone dissolution with methyl-tert-butyl ether (MTBE) and transcutaneous ultrasound energy

The simultaneous application of ultrasound energy greatly accelerated the rate of cholesterol gallstone dissolution by methyl-tert-butyl ether (MTBE). In vitro experiments using this treatment showed that a 498-mg stone burden could be dissolved in 19.5 minutes, approximately 100% faster than what could be achieved with MTBE alone. Pigs (n = 13) with surgically implanted gallstones were treated with MTBE and transcutaneously applied ultrasound from a prototype system built for clinical studies. The average stone reduction of all pigs was 470.46 mg +/- 60.44 mg; 91.39% of an average implanted burden of 515.08 +/- 18.03 mg. Control group pigs (n = 9), receiving only an MTBE infusion, showed an average stone reduction of 51.77%. Enzymes indicative of hepatocellular injury showed no significant abnormalities after 6 weeks. Gallbladder ablation with a fibrous remnant (ie, no mucosa, no lumen, patent cystic duct) occurred in 10 (70%) of the pigs.