The Efficacy of a Fully Covered Self-expandable Metal Stent Anchored by a Plastic Stent for Anti-migration in the Management of Malignant Biliary Strictures: a Prospective Randomized Controlled Study

Endoscopic retrograde biliary drainage using a plastic stent for the treatment of malignant biliary stricture has advantages in that it is easy to perform and low cost, but it has a short period of patency. To overcome this drawback, self-expandable metal stents (SEMS) have been developed and are now widely used. But, over time, the SEMS also develop restenosis, due to tumor ingrowth and the tissue hyperplasia caused by the stimulation of the surrounding tissues by the metal thin wire. To overcome these disadvantages, a fully covered self-expandable metal stents (FCSEMS) covered with a polymer coating have been developed and used. However, the FCSEMS showed more stent migration than the uncovered SEMS, which was not superior to the uncovered SEMS in terms of loss of stent function. In order to overcome the limitations of the FCSEMS, small-scale studies have shown that stent migration can be reduced by anchoring the FCSEMS using a plastic stent. To date, there has been no randomized controlled study to determine whether the FCSEMS can be anchored with a plastic stent in patients with malignant biliary stricture to reduce the stent migration. Therefore, the purpose of this study is to evaluate the efficacy of plastic stent anchoring to reduce migration of FCSEMS.