Safety and efficacy of transpapillary bridged bilateral side-by-side stenting for unresectable malignant hilar biliary obstruction

To the Editor:Biliary drainage is most frequently performed among endoscopic procedures using pancreatobiliary endoscopy.A large-diameter metallic stent can significantly extend the patency period rather than a plastic stent for extrahepatic biliary stricture.[1] However, the optimal drainage for the hilar biliary obstruction is still controversial.Various techniques have been attempted for unresectable malignant hilar biliary obstruction.[2] There are also some controversies regarding unilateral versus bilateral liver drainage.[3, 4] Recent studies have reported that at least 50% drainage of liver volume achieves sufficient efficacy or longer survival in patients with malignant hilar obstruction.[3, 5] Therefore, multiple kinds of endoscopic placements of self-expandable metallic stents (SEMSs)may be required. However, despite recent innovations in endoscopic technology, bilateral SEMS placement may be difficult and challenging. As the reasons, insert a second stent through tight stricture, adjustment of the lower end of the SEMSs, and re-intervention under fluoroscopy are difficult associated with bilateral side-by-side stenting.