Combination of extracorporeal shock-wave lithotripsy and dissolution of gallbladder stones with methyl tert-butyl ether: a randomized study.

We conducted a prospective randomized study in gallstone patients to determine whether a combination of extracorporeal shock-wave lithotripsy and subsequent dissolution with methyl tert-butyl ether increases the success rate of methyl tert-butyl ether dissolution and shortens treatment time compared with monotherapy with methyl tert-butyl ether. Fifty patients were randomized into two groups. Twenty-five patients underwent extracorporeal shock-wave lithotripsy before contact dissolution with methyl tert-butyl ether, and 25 patients were treated with methyl tert-butyl ether alone. All patients had at least three stones or stones larger than 30 mm that were radiolucent on x-ray and had densities of less than 140 Hounsfield Units (HU) on computed tomography. Overall, the combined approach neither shortened the treatment time significantly vs. monotherapy with methyl tert-butyl ether nor reduced the time of hospitalization. The success rate was slightly but not significantly increased compared with that of methyl tert-butyl ether therapy alone. The recurrence rate was similar in the two groups after a median follow-up of 1 yr. However, when subgroups of patients with at least one stone larger than 15 mm or with stones with densities of more than 60 HU were analyzed, the clearance rate after 5 mo was significantly higher (p < 0.005 and p < 0.025, respectively) in patients subjected to a combination of extracorporeal shock-wave lithotripsy and methyl tert-butyl ether dissolution. Extracorporeal shock-wave lithotripsy and methyl tert-butyl ether did not expose patients to more adverse effects than did treatment with methyl tert-butyl ether alone.