Stent placements are used to treat the narrowing, or stricture, of bile ducts caused by benign or malignant diseases. A stent is a plastic or metal tube that is placed into the bile duct. There are a number of conditions, malignant or benign, that can cause stricture of the bile ducts. Malignant causes include pancreatic cancer and cancers of the gallbladder, bile duct, liver, and large intestine. Noncancerous causes of bile duct strictures include injury to the bile ducts during surgery for gallbladder removal, pancreatitis, primary sclerosing cholangitis, gallstones, radiation therapy, or blunt trauma to the abdomen.