("Bile Ducts"[Mesh] OR "Common Bile Duct Diseases"[Mesh] OR biliary) AND ("Constriction, Pathologic"[Mesh] OR strict* OR constrict*) AND benign* AND ("Stents"[Mesh] AND (metal OR metallic OR metals OR self-expandable metal stents OR covered metal stents) AND (“ERCP”[Mesh] AND (endoscopic OR endoscopic retrograde cholangiopancreatography) AND “Case-Control Studies”[Mesh:noexp] OR "retrospective ...