The Use of Multi Holes Fully Covered Metallic Stents Versus Uncovered and Partially Covered Metallic Stents in the Management of Malignant Biliary Obstruction: Randomized Parallel Clinical Trial.

Malignant biliary obstruction is still a diagnostic and therapeutic challenge requiring a multidisciplinary approach. Most cases are inoperable at the time of diagnosis. Relieving the obstruction and normalizing the serum bilirubin level is usually the first step by biliary catheterization and stent placement.

Biliary stent placement has largely replaced surgical bypass for the palliation of malignant biliary obstruction. Rigid plastic stents, despite it is cheap and easily removed, but with limited duration of stent patency. Self-expandable metal stents (SEMS) have larger luminal diameters and provide longer patency time than rigid plastic stents. SEMS are composed of a variety of metals and can be uncovered, partially covered, or fully covered.

Uncovered stents are prone to obstruction by tumor growths; however, covered stents may block bile duct branches and are at risk of migration. A multihole self-expandable metallic stent was developed to prevent the obstruction of bile duct branches. In addition, the holes may prevent migration due to small ingrowths which reduce the tension of the membrane