Reply to Dr. Viroj Wiwanikit

Management of an occluded biliary metallic stent

In patients with a malignant biliary obstruction who require biliary drainage, a self-expandable metallic stent (SEMS) provides longer patency duration than a plastic stent (PS). Nevertheless, a stent occlusion by tumor ingrowth, tumor overgrowth and biliary sludge may develop. There are several methods to manage occluded SEMS. Endoscopic management is the preferred treatment, whereas percutaneous intervention is an alternative approach. Endoscopic treatment involves mechanical cleaning with a balloon and a second stent insertion as stent-in-stent with either PS or SEMS. Technical feasibility, patient survival and cost-effectiveness are important factors that determine the method of re-drainage and stent selection.

Role of fully covered self-expandable metal stent for treatment of benign biliary strictures and bile leaks

Endoscopic therapy by balloon dilation and placement of multiple large-bore plastic stents is the treatment of choice for benign biliary stricture. This approach is effective but it typically requires multiple endoscopic sessions given the short duration of stent patency. The endoscopic approach for treatment of bile leak involves the placement of a stent with or without biliary sphincterotomy. The self-expandable metal stent (SEMS) has traditionally been used for palliation of malignant biliary strictures given the long duration of stent patency owing to their larger stent diameter. Recently, SEMS has been used in a variety of benign biliary strictures and leaks, especially with the design of the covered self-expandable metal stent (CSEMS), which permits endoscopic-mediated stent removal. The use of CSEMS in benign biliary stricture could potentially result in a decrease in endoscopic sessions and it is technically easier when compared to placement of multiple plastic stents. However, complications such as cholecystitis due to blockage of cystic duct, stent migration, infection and pancreatitis have been reported. The potential subsegmental occlusion of contralateral intrahepatic ducts also limits the use of CSEMS in hilar stricture. Certain techniques and improvement of stent design may overcome these challenges in the future. Thus, CSEMS may be appropriate in only highly selected conditions, such as refractory benign biliary stricture, despite multiple plastic stent placement or difficult to treat bile duct stricture from chronic pancreatitis, and should not be used routinely. This review focuses on the use of fully covered self-expandable metal stent for benign biliary strictures and bile leaks.