Endoscopic bilateral stenting of malignant hilar bile duct obstruction using novel partially covered self-expandable metal stents.

Endoscopic bilateral stenting using conventional metal stents is considered to be technically difficult in patients with malignant hilar bile duct obstruction because the second stent is not easily inserted through the cell of the first stent wall in the bile duct [1]. A variety of new self-expandable metal stents (SEMS) specially designed for stent-in-stent procedures to facilitate bilateral stents deployment have been recently reported [1–5]. We report two cases of malignant hilar bile duct obstruction which were managed by endoscopic bilateral stenting using novel metal stents (KEY stents; S&G BioTech Inc., Seongnam, Korea). These stents are self-expanding Nitinol stents partially covered with a silicone membrane and consisting of a body stent (first stent) and a limb stent (second stent). The body stent is composed of a body and two legs: a long leg and a short leg. The short leg facilitates insertion of a guide wire into the contralateral intrahepatic bile duct (IHD) for the limb stent (●" Fig.1). After placement of the body stent to one side of both IHDs across the hilar stricture, the limb stent is introduced into another IHD through the short leg of the body stent (●" Fig.2). We successfully carried out endoscopic bilateral stenting using these stents in two patients withmalignant hilar bile duct obstruction without early complications. One patient had gallbladder cancer with invasion of the hilar bile duct (●" Fig.3) and the other had colon cancer with liver and hilar bile duct metastases (●" Fig.4). The novel stents have some advantages in the palliative management of malignant hilar bile duct obstruction: The second stent can be easily inserted into the contralateral IHD through the opening of the short leg after the insertion of the first stent; and the central part of the stents are covered by a membrane to prevent tumor ingrowth. However, there are also some limitations to the use of these stents. First, they have to be tailored to the extent of the stricture in each individual patient. Second, it is difficult to use them in patients with advanced malignant hilar biliary obstruction in which numerous branches are occluded. Finally, it is difficult to make the short leg of the first stent to face in the direction of the contralateral IHD during the insertion of the first stent. In conclusion, endoscopic bilateral stent placement using the novel partially covered SEMS may be a useful treatment option in malignant obstruction of the hilar bile duct.