What Is Fully Covered Self Expandable Metal Stents for Treatment of Benign Biliary Strictures?

Fully covered self-expandable metal stents (FCSEMS) are a special type of stent used to treat benign biliary strictures in the bile ducts. 

Some key points:

- Material: They are made from metal alloys like nitinol or stainless steel. The metal mesh is fully encapsulated in a thin silicone or polymer coating.

- Design: The coating prevents tissue ingrowth into the stent, allowing it to be easily removed later. Uncovered stents have an ingrowth risk making removal difficult.

- Expansion: Like other self-expanding stents, they expand on their own when deployed to widen the narrowed bile duct.

- Removability: The non-stick coating allows FCSEMS to be relatively easily removed after 6-12 months once the stricture has healed. Uncovered stents often require invasive surgery for removal.

- Use: FCSEMS are designed for treating benign biliary strictures which have a good chance of resolving after a period of stenting. Once the stricture has resolved, the stent can be taken out.

- Benefits: The temporary stenting helps dilate the narrowed duct while minimizing complications associated with tissue ingrowth into the stent. 

So in summary, fully covered self-expanding metal stents provide temporary dilation of benign biliary strictures and can be retrieved once their purpose is served, avoiding permanent placement. The non-stick coating prevents ingrowth.