This will be a comparative study of methods, prospective, randomized study assessing the successful removal of bile duct stones considered to be difficult between the two proposed methods. A total of 100 patients will be recruited, according to the criteria for inclusion / exclusion of Appendix I. Randomization will be performed using a computer generated system. Fifty patients will be distributed in group 1 (Spyglass + electrohydraulic lithotripsy) and fifty in group 2 (with hydrostatic balloon dilation of the papilla with a extractor balloon sweep). Endoscopic retrograde cholangiopancreatography (ERCP) will be performed, and after the diagnosis of difficult stone, will be followed by randomization between the two proposed methods. In group 1, the examination with the Direct Visualization System of Bile Ducts ("Spyglass Direct Visualization System") will be held soon after the diagnosis of difficult stone and partial endoscopic papillotomy. After access to the biliary duct with the system described, and the visualization of the stone, it will be introduced gently through the working channel of a spyglass the probe to perform the electrohydraulic lithotripsy. When the fragmentation is complete the system spyglass will be removed and the pieces of stone are removed by conventional endoscopic methods. In group 2, after the diagnosis of difficult calculi and performing the partial endoscopic papillotomy, the papilla (as with papillotomy) will be dilated with a hydrostatic balloon until the maximum size allowed by the diameter of common bile duct, followed by scanning with extractor balloon. In both groups, the stone clearance will be confirmed using Spyglass cholangioscopic exploration of the bile duct. In case of failure in stone removal by some of the methods studied, it will be performed biliary drainage with plastic stent.