In vitro studies of gallstone dissolution using bile salt solutions and heparinized saline

A controlled in vitro study of gallstone dissolution has been carried out using a model designed to simulate the in vivo situation in the bile ducts. Sodium taurocholate, sodium cholate, heparinized saline and physiological saline were infused for 10 days over 81 stones from 32 patients and changes in weight and structure were recorded. The bile salt solutions caused weight loss in 81-5 and 85-7 per cent respectively of the stones treated, but the two saline solutions caused weight gains in 74-5 and 88 per cent respectively. Fragmentation occurred in 18-5% of stones treated with sodium taurocholate, in 25% of those treated with sodium cholate and in 11-8 per cent of those treated with heparinized saline. Small stones lost a lower absolute amount of weight than large stones but this represented a greater proportion of their initial weight. These investigations confirm the advantages of a dynamic in vitro model to study gallstone dissolution. Bile salt solutions infused into the bile ducts may clear retained stones by causing reduction in stone weight or fragmentation or both, but heparinized saline appears to be unsuitable for gallstone dissolution. Larger stones may require longer periods of infusion.