Biliary extracorporeal shockwave lithotripsy: short-term and long-term observations in an animal model

The short- and long-term effects of biliary extracorporeal shockwave lithotripsy (ESWL) using an electromagnetic lithotriptor were investigated in 26 pigs. After implantation of single human gallstones into their gallbladders, all but 4 control pigs were subjected to 4,000 or 8,000 shock waves and killed one day (n = 9), one week (n = 7), or one year (n = 6) thereafter. Post-ESWL, no abnormalities of chest radiographs or laboratory tests were detected. Apart from focal injury of the gallbladder and liver, in 4 out of 9 pigs subpleural pulmonary hemorrhages were found one day post-ESWL. However, tissue damage was largely reversed within one week and after one year only small hepatic scars persisted as permanent damage. Stone fragmentation occurred in 19 (86%) out of 22 pigs, and was adequate (fragments < or = 5 mm) in 9 (41%) pigs. Tissue damage and stone fragmentation after 4,000 as compared with 8,000 shock waves were not significantly different. These data warrant further evaluation of this lithotriptor in human studies.