Microprocessor-assisted solvent transfer system for effective contact dissolution of gallbladder stones

To solve the problems that arise during the dissolution of cholesterol gallbladder stones by manual lavage with methyl tert-butyl ether (MTBE) via a percutaneous indwelling gallbladder catheter, a microprocessor-assisted solvent transfer (MST) system was developed. The system consists of a three-lumen catheter, dual peristaltic pumps, a pressure transducer, and a microprocessor controller which regulates pump rate according to the measured intraluminal gallbladder pressure. The two pumps simultaneously infuse and aspirate from the gallbladder via two of the catheter lumens; intraluminal pressure above a set limit causes infusion to cease while aspiration continues, thus lowering the pressure and preventing overflow of gallbladder contents into the biliary tract. In vitro evaluation showed that the system´s response was 156 fold faster than the natural rate of gallbladder emptying. These in vitro studies suggest that the MST system is capable of rapid, complete, and fully automatic contact dissolution of cholesterol gallbladder stones using MTBE or similar lipid solvents.