Prevention of stent migration of covered self-expandable metal stents in distal malignant biliary obstruction: a review of literature.

Distal malignant biliary obstruction (dMBO) is a common complication of advanced malignancies, particularly pancreatic cancer and biliary tract cancer, requiring biliary drainage to relieve symptoms. Endoscopic drainage using self-expandable metal stents (SEMS) is widely preferred due to improved long-term patency compared with plastic stents. However, the choice between fully covered SEMS (FCSEMS) and uncovered SEMS (UCSEMS) remains controversial, primarily due to migration risks associated with FCSEMS. Recent advances in stent design, such as anchoring flaps, flared ends, and anti-migration coatings, have been developed to improve FCSEMS stability. Additionally, techniques incorporating double-pigtail plastic stents as internal or external anchors have demonstrated significant reductions in migration rates. This review examines the current literature and evaluates various anti-migration strategies for FCSEMS, highlighting the clinical efficacy and challenges associated with each approach. Understanding these innovations is crucial for optimizing stent selection and improving patient outcomes in dMBO.