Lithotripsy in the common bile duct using ultrasound. Preliminary in vitro experiments

In patients with an increased surgical risk, common bile duct stones can be removed with the aid of endoscopic papillotomy. Most stones are either passed spontaneously, or can be drawn out with the Dormia basket. Excessively large stones can first be smashed with the mechanical lithotripter. Some 20% of the stones presenting are, however, too hard to be smashed in this way. A technique was accordingly developed for smashing such bile duct stones using ultrasound. A prerequisite for this technique was the development of an acoustic wave guide that would conduct ultrasound energy even when bent. With this procedure, it will soon be possible to destroy bile duct stones in situ.