Randomized Trial of Combination of Cholangioscopic Guided Laser Lithotripsy and Conventional Mechanical Versus Conventional Mechanical Methods for the Endoscopic Removal of Large Bile Duct Stones

TITLE: Randomized trial of combination of cholangioscopic guided laser lithotripsy and conventional mechanical versus conventional mechanical methods for the endoscopic removal of large bile duct stones

STUDY ARMS: Laser guided lithotripsy and conventional methods vs conventional methods alone alone

BACKGROUND AND HYPOTHESES: Large bile duct stones are challenging to remove at time of endoscopic retrograde cholangiopancreatography (ERCP) and classically have required the utilization of mechanical baskets and balloons. These maneuvers may be associated with bile duct trauma, bleeding, pancreatitis, and the requirement for additional procedures. Many patients require multiple sessions using conventional mechanical approaches. A recent prospective audit of patients undergoing ERCP during the past year at LAC+USC Medical Center indicates that of approximately 500 procedures more than 250 were for bile duct stones and 100 (40%) required multiple procedures and stent placement. Scheduling challenges and limited resources make it difficult for many of these patients to return for stent changes and increases the risk of complications including cholangitis.

Cholangioscopy enables therapeutic intervention including intracorporeal electro-hydraulic and laser lithotripsy for biliary stone disease with favorable efficacy and safety. Direct visualization by cholangioscopy minimizes the risk of laser related bile duct injury and is potentially much less traumatic and more efficacious than traditional mechanical approaches.

A recent 15 center prospective clinical cohort study demonstrated a high success rate, 89%, and low rate of complications, 7.5%, for the single user cholangioscopy system. In a group of patients who underwent stone removal using the cholangioscope introduced laser or electrohydraulic systems the success even higer 92% and complications potentially lower. Available literature indicates that in cases in which ERCP with mechanical lithotripsy is required the complication rate is approximately 5-12% and risk of cholangitis is 1.4-4%. If ERCP is performed with laser lithotripsy in addition to conventional mechanical methods the complications rate is 6.1% and risk of cholangitis is 2.4%. Cholangioscopy guided laser treatment to enhance stone removal is currently widely used by gastroenterologists at academic centers including the hospitals of the University of Southern California as well as in leading community centers such as the Kaiser Permanente Hospitals of Southern California. While it is a standard of care procedures for large bile duct stones studies directly comparing its efficacy to traditional mechanical approaches are needed.