Plasma shock wave lithotripsy of gallstones in vitro. Animal experiments and clinical application.

It is sometimes very difficult to extract a huge impacted stone through the T-tube fistulous tract by conventional techniques with choledochoscope. To simplify the procedure, a lithotriptor PSW-G type using plasma shock wave to disintegrate the stone was designed. The efficacy to fragmentate stone was investigated both in vitro and in vivo. Stones can be shattered into pieces less than 3 mm in diameter in about 30 times of spark with lower energy ranging from 1.7-3.4 kV and 1-3 J. Animal experiments were carried out to prove the safety of the lithotriptor. There was neither interference with the cardiovascular and respiratory systems nor obvious damage to the adjacent tissue where plasma shock wave applied to break stones. Six patients with retained calculi impacted both in extra- and intra-hepatic duct were successfully treated by plasma shock wave lithotripsy. It appears very useful in dealing with a huge impacted stone in the biliary tract.