Fragmentation of bile duct stones: a prospective systematic in vitro evaluation of argon plasma coagulation, cryotechnology, and water-jet technology.

ABSTRACT

BACKGROUND AND STUDY AIM: Choledocholithiasis is a common disease in the West. Lithotripsy by mechanical methods using baskets and by laser or electrohydraulic methods varies in effectiveness. With argon plasma coagulation (APC), high temperatures are used for devitalization and fragmentation; cryogenic techniques use the selective controlled application of freeze-thaw cycles to devitalize pathological tissue; and the dissecting water jet exploits the high pressure action of a thin laminar jet. We aimed to assess the feasibility and effectiveness of APC, cryotechnology, and the dissecting water jet as options for the fragmentation of bile duct stones. METHODS: In an in vitro feasibility study, we evaluated the fragmentation of 120 bile duct stones treated with the three methods. Primary measures were assessment of the fragmentation rate, fragmentation effect, and energy application for each technology. RESULTS: Fragmentation was seen in only 10 % of stones treated cryogenically using liquid nitrogen. APC at a power setting of 30 - 50 W fragmented all the cholesterol stones, but results with hard pigment stones were unsatisfactory even at high energies of a 100 W setting and long application time. Using the water jet, all 40 stones (100 %) were cracked effectively and completely with a pressure of 10 - 50 bar. CONCLUSION: In this feasibility study, the first of its kind, only the water-jet device demonstrated efficient fragmentation of large bile duct stones in vitro. APC and cryotechnology are not suitable for the treatment of bile duct stones; the fragmentation rate with these methods was inadequate.