See ‘ERCP’ prior to reviewing this section. When ERCPs are done to allow some sort of treatment, they are referred to as therapeutic ERCPs. Possible therapies include sphincterotomy, stone removal, stent placement, balloon dilation, and tissue sampling. A sphincterotomy involves cutting the muscle surrounding the opening of the ducts, or papilla, in order to enlarge the opening. This cut allows access to the duct and improves drainage. Instruments can then be advanced up the duct to perform stone removal. This refers to stones that may have either formed in the gallbladder and traveled down the bile duct, or stones that may have formed years after having your gallbladder removed. Stent placement (either plastic or metal) involves placement of small straw-like devices into the bile or pancreatic duct to bypass strictures (narrowings) or to facilitate drainage. Narrowings in the ducts can also be treated withballoon dilation, in which a small balloon is inflated to stretch out the narrowing. In addition, tissue samplings can be taken from these areas to help decide if a stricture is due to cancer. Again, please refer to the ‘ERCP’ section for a discussion of possible complications of therapeutic ERCP, which can occur in ~5% of cases. Of note, the risk of complications is higher in a therapeutic ERCP than in a diagnostic ERCP (in which Dr. Mauer just looks at the ducts).