Selection of patients for dissolution of retained common duct stones with mono-octanoin.

Mono-octanoin is effective in the dissolution of retained common duct stones. Some of the failures of this solution to dissolve retained common duct stones are attributed to the low cholesterol content of the stones. This assumption was evaluated by analyzing gallbladder stones from 58 patients following cholecystectomy. Each stone was also incubated in mono-octanoin, and the composition of the stone was compared with the rate of dissolution. Stones containing 10% or less cholesterol did not appreciably dissolve in mono-octanoin. Stones 40% or greater in cholesterol content dissolved within an average of 3.3 days, which was significantly faster than those low in cholesterol (p less than 0.001). Following common duct exploration, stones should be saved for analysis or in vitro determination of the rate of dissolution in mono-octanoin. The use of mono-octanoin is recommended only for retained stones that are high in cholesterol or dissolve rapidly when incubated in mono-octanoin and should be effective in 91% of the cases.