Methyl tert-butyl ether fails to dissolve retained radiolucent common bile duct stones

Methyl tert-butyl ether (MTBE) has been recently proposed as a new therapeutic modality for the dissolution of cholesterol gallstones. To further evaluate efficacy and tolerability of this new litholytic agent, we have administered MTBE to 3 patients with nonobstructive radiolucent common bile duct stones after recent surgery. Methyl tert-butyl ether (8-11 ml/day) was infused after aspiration of bile via a Teflon catheter inserted through the postoperative T tube. Gentle aspiration and reinfusion were performed continuously to generate stirring. The total amount of MTBE retrieved during the entire procedure was equivalent to approximately 30% of the volume infused. In all cases, MTBE failed to dissolve the radiolucent stones, which were then dissolved with continuous infusion of monooctanoin via the biliary catheter. The characteristic odor of MTBE was detected on the breath of the patients, and nausea and somnolence developed during the treatment. Serum hepatic and pancreatic enzymes did not change after MTBE. In the third subject, who received 11 ml/day of MTBE for 2 consecutive days (total of 22 ml), histologic evidence of duodenitis was found around the papilla. In our opinion, the lack of efficacy of MTBE in dissolving retained radiolucent common bile duct stones was mainly related to its leakage from the common bile duct into the duodenum and the ensuing local chemical toxicity and systemic absorption. As MTBE needs a persistent stone-solvent contact to exert its litholytic action and, at the same time, its toxicity prevents the infusion of larger doses, MTBE use should be restricted to stones placed in closed chambers, such as the gallbladder.