Biliary lithotripsy. Determination of stone fragmentation success and potential tissue injury in swine.

Application of extracorporeal shock wave lithotripsy to gallbladder stones was studied in 37 adult female swine. Twenty-two sows underwent cholecystostomy with implantation of human gallstones. In 20 animals, after a 10-day recovery period, extracorporeal shock wave lithotripsy, 2000 shocks (an amount determined in preliminary water bath studies to be effective), was performed. In 10 of these implanted swine, frequent focal point refocusing and biplanar ultrasonography were employed. Two animals served as operative controls. Fifteen other animals without gallstone implantation were studied for adverse effects of extracorporeal shock wave lithotripsy on tissue. These animals (unimplanted) received 5000 shocks; 7 animals were killed 1 to 4 days after treatment and the others were killed after 4 weeks. Biochemical tests (total bilirubin, alkaline phosphatase, lipase, amylase, alanine aminotransferase, and lactate dehydrogenase determinations) were performed on all animals at entry and every second or third day until they were killed. Successful fragmentation, defined as all residual gallstone fragments being less than or equal to 4 mm in greatest dimension, was achieved in 14 of 20 animals overall, but in 10 of 10 animals in which focal point refocusing had been used. Slight perivascular hemorrhage and minimal coagulation necrosis were seen histologically only in the liver parenchyma adjacent to the gallbladder bed. The remainder of the liver was grossly and histologically normal. No injuries to the colon, duodenum, common bile duct, or pancreas were observed. No alterations suggesting injury or altered function occurred in any of the biochemical tests.