The vast majority of SEMS are used to alleviate symptoms caused by cancers of the gastrointestinal tract that obstruct the interior of the tube-like (or luminal) structures of the bowel — namely the esophagus, duodenum, common bile duct and colon.

Self-expandable metallic stents are cylindrical in shape, and are devised in a number of diameters and lengths to suit the application in question.

[1] They typically consist of cross-hatched, braided or interconnecting rows of metal that are assembled into a tube-like structure.

SEMS, when unexpanded, are small enough to fit through the channel of an endoscope, which is meant for delivery of devices for therapeutic endoscopy.

The usual applications are for cancers of the esophagus, pancreas, bile ducts and colon that are not amenable to surgical therapy.

[9] SEMS and self-expanding plastic stents have also been used for non-malignant conditions that cause narrowing or leaks of the esophagus or colon.

[citation needed] Self-expandable metallic stents are typically inserted at the time of endoscopy, usually with assistance with fluoroscopy or x-ray images taken to guide placement.

As a result, radio-opaque markers are usually placed on the surface of the patient to mark the area of narrowing on fluoroscopy.

The bile duct is cannulated with the assistance of a guidewire and the sphincter of Oddi that is located at its base is typically cut.

The first is that the endoscopic procedure used to insert a SEMS involves the use of sedative medications, which may lead to oversedation, aspiration, or drug reaction.