Narrowed areas may be bridged by a [[stent]], a hollow tube that keeps the duct open. Removable plastic stents are used in uncomplicated gallstone disease, while permanent [[Self-expandable metallic stent|self-expanding metal stents]] with a longer lifespan are used if the obstruction is due to pressure from a tumor such as [[pancreatic cancer]]. A nasobiliary drain may be left behind; this is a plastic tube that passes from the bile duct through the stomach and the nose and allows continuous drainage of bile into a receptible. It is similar to a [[nasogastric tube]], but passes into the common bile duct directly, and allows for serial x-ray cholangiograms to be done to identify the improvement of the obstruction. The decision on which of the aforementioned treatments to apply is generally based on the severity of the obstruction, findings on other imaging studies, and whether the patient has improved with antibiotic treatment.<ref name=Kinney/> Certain treatments may be unsafe if [[coagulation|blood clotting]] is impaired, as the risk of bleeding (especially from sphincterotomy) is increased in the use of medication such as [[clopidogrel]] (which inhibits [[platelet]] aggregation) or if the [[prothrombin time]] is significantly prolonged. For a prolonged prothrombin time, [[vitamin K]] or [[fresh frozen plasma]] may be administered to reduce bleeding risk.<ref name=Kinney/>
In cases where thea patientperson is too ill to tolerate endoscopy or when a retrograde endoscopic approach fails to access the obstruction, a [[percutaneous transhepatic cholangiography|percutaneous transhepatic cholangiogram]] (PTC) may be performed by an [[Interventional radiology|Interventional Radiologist]] to evaluate the biliary system for placement of a percutaneous biliary drain (PBD).<ref>{{Cite journal|last=García-García|first=Lorenzo|last2=Lanciego|first2=Carlos|date=2004-03-01|title=Percutaneous Treatment of Biliary Stones: Sphincteroplasty and Occlusion Balloon for the Clearance of Bile Duct Calculi|url=http://www.ajronline.org/doi/10.2214/ajr.182.3.1820663|journal=American Journal of Roentgenology|volume=182|issue=3|pages=663–670|doi=10.2214/ajr.182.3.1820663|issn=0361-803X}}</ref><ref name="Williams" /> This is often necessary in the case of a proximal stricture or a bilioenteric [[Anastomosis#Medicine|anastomosis]] (a surgical connection between the bile duct and small bowel, such as the [[duodenum]] or [[jejunum]]).<ref name="schwartz" /> Once access across the stricture is obtained, balloon dilation can be performed and stones can be swept forward into the duodenum.<ref>{{Cite journal|last=García-García|first=Lorenzo|last2=Lanciego|first2=Carlos|date=2004-03-01|title=Percutaneous Treatment of Biliary Stones: Sphincteroplasty and Occlusion Balloon for the Clearance of Bile Duct Calculi|url=http://www.ajronline.org/doi/10.2214/ajr.182.3.1820663|journal=American Journal of Roentgenology|volume=182|issue=3|pages=663–670|doi=10.2214/ajr.182.3.1820663|issn=0361-803X}}</ref>. Due to potential complications of percutaneous biliary drain placement and the necessity of regular drain maintenance,<ref name="schwartz" /> a retrograde approach via ERCP remains first-line therapy.<ref name="Kinney" />
