Extracorporeal lithotripsy of bile duct stones using ultrasonography for stone localization

In 19 patients, extraction of bile duct stones through the papilla using a Dormia basket or a mechanical lithotripter was not possible following endoscopic sphincterotomy. After the insertion of a nasobiliary drain, extracorporeal lithotripsy was performed with intravenous sedation using an ultrasonographic stone localization system. The number and location of stones were first determined by retrograde cholangiography. At the time of lithotripsy, saline was injected in the bile ducts to modify the acoustic impedance of tissues surrounding the stones, and subsequent ultrasonography was effective in localizing all stones present in 4 of 5 (80%) patients with intrahepatic stones, and 13 of 14 (93%) with common bile duct stones. In 10 patients (53%), fragmentation was satisfactory and the bile ducts were cleared completely. The mean single stone diameter was significantly smaller in successful cases of fragmentation compared with failures (22.8 +/- 6.6 mm vs. 40 +/- 10 mm). The results in patients with multiple stones were significantly worse than those in patients with single stones of similar size (25% vs. 100% successful fragmentation). Reasons for this difference in results included the small size of the focal area and the reduced ability of ultrasonography (1) to adequately visualize multiple calculi individually and (2) to assess the degree of stone destruction. Care was taken to first await the resolution of infection or the correction of coagulation abnormalities when present; no morbidity following extracorporeal lithotripsy was observed. Despite its 3-step approach (endoscopic sphincterotomy, lithotripsy, and endoscopic extraction), the need for only intravenous sedation and the absence of patient immersion in water render this technique attractive for elderly and frail patients.