Chemolysis of gallbladder debris left over after contact litholysis with methyl tert-butyl ether

Rapid and safe gallbladder clearance from residual, post-MTBE stone debris is believed to be absolutely necessary to reduce stone recurrence after contact litholysis. Because the clearing effect of prokinetic agents is considered an uncertain postdissolution trial, we investigated by in vitro experiments whether and to what extent debris from various cholesterol and "mixed stones" could be removed by direct (topical) chemolysis. Debris from radiolucent cholesterol stones could be dissolved very easily, using the aqueous solvent S-01, composed of EDTA-2Na (1-2%), lauryl sulfobetaine-12 (0.1 M), and 0.1 M sodium carbonate/boric acid buffer, pH 9,5. Its dissolution capacity (DC) was 8.06 +/- 2.3 mg debris/ml and its dissolution efficacy (DE) was 16.2 +/- 4.6 mg debris/ml/hr. Debris from mixed, slightly to moderately calcified stones needed another treatment with S-05, composed of sodium citrate (0.25 M), lauryl sulfobetaine-12 (0.01 M), and citric acid. The initial pH was 5.2. The DC of S-05 ranged from 1.61 +/- 1.1 (debris enriched with Ca-phosphate) to 3.94 +/- 1.3 mg/ml (debris enriched with Ca-carbonate). Stones which did not respond immediately to MTBE because of a thin rim of inorganic or/and organic Ca salts could be made ready for MTBE litholysis by pretreatment with S-01 or S-05 or with a combination of both solvents. Debris containing large portions of biliary mucus could be dissolved most effectively by successive application of S-01 and S-06 (2 M urea).