Contact dissolution

In contact dissolution of gallstones, methyl tert-butyl ether (MBTE) or n-propyl acetate is repeatedly infused and withdrawn from the gallbladder through a catheter placed percutaneously under ultrasound guidance or at ERCP. The patient is sedated and has a local anaesthetic.

Results are good. In carefully selected patients, over 95% of the stone mass may be dissolved within 12 hours.

Potential problems with the procedure include:

• MBTE only dissolves cholesterol gallstones
• length of the procedure - dissolution is performed over a minimum of 12 hours
• duodenal inflammation from the introduction of solvent into the common bile duct and duodenum - computerised systems are now used to regulate the passage of solvent and its escape into the distal biliary tree is avoided by the maintenance of constant pressure

Indications for dissolution are becoming increasingly few since the advent of laparoscopic cholecystectomy. It may have a niche in the treatment of bile duct stones.