What is a fully covered metal stent esophageal?

A fully covered metal stent for the esophagus is a specific type of esophageal stent that has the following key features:

- Material: The stent is composed of a metal alloy, usually nitinol (nickel-titanium alloy) or stainless steel.

- Mesh design: The metal is in a tubular mesh configuration that allows the stent to expand and widen the esophageal lumen.

- Fully covered: The metal mesh is completely encapsulated in a covering material, typically silicone, plastic (polyurethane), or fabric. 

- Self-expanding: The metal stent can spontaneously expand when deployed to widen the stricture. This allows non-surgical placement.

- Removable: The full covering prevents tissue ingrowth, making fully covered metal esophageal stents more easily removable later.- Indications: Used to provide palliative treatment for malignant esophageal strictures from cancer or other esophageal conditions like fistulas.

- Duration: Fully covered metal esophageal stents are temporary devices, lasting weeks to months before needing replacement.

- Limitations: More prone to migration compared to uncovered or partially covered stents. The covering may also impede the esophageal side branches. 

Overall, the fully covered design prevents tumor ingrowth and permits removability but may have a higher risk of complications like migration. Regular monitoring is important if using fully covered metal esophageal stents.