Ever since it was generally concluded that endoscopic retrograde cholangiopancreatography (ERCP) and sphincterotomy was the treatment of choice for choledocholithiasis, big bile duct stones have remained a major challenge for the endoscopist. Extending a sphincterotomy increases risk of bleeding and perforation, mechanical lithotripters are generally expensive, cumbersome to use, fragile, and fail to grasp the stones effectively in a significant proportion of cases. Intraduct solvents such as mono octanoin or methyl tert butyl ether are ineffectual or dangerous, or both. The somewhat defeatist approach of placing stents in elderly patients can lead to stent migration with occasional serious consequences or the formation of multiple stones above the stent, with the consequent risk of further cholangitis. There is probably a place at a few referral centres for extracorporeal shock wave lithotripsy (ESWL) but this requires some sort of biliary catheter to deliver x ray contrast medium to facilitate targeting, which usually means at least two ERCPs in addition to the lithotripsy sessions. Furthermore, not all stones fragment easily and the capital costs and low usage mean that endoscopists must borrow sessions from …