Covered Versus Uncovered Metal Stents for the Drainage of the Malignant Distal Biliary Obstruction With ERCP: A Systematic Review and Meta-Analysis.

Introduction And Aim: Unresectable malignant distal biliary obstruction is a condition that should be treated with drainage and clearance of the biliary duct. self-expanded metal stents (SEMS) are known to be better and more effective than plastic stents because the patency is longer. The actual evidence is insufficient to recommend if it is better the use of SEMSu over SEMSc or vice versa for the drainage of the malignant distal biliary obstruction during ERCP.