Abstract: An expandable device, e.g. a stent for insertion into a passage, e.g. a blood vessel or artery, is disclosed. The device has a body (20) formed of a flexible material. The body is convertible from a collapsed condition in which it is of a size to be inserted into the passage into an expanded condition in which the body (20) is fixed relative to the passage. A passage (28) is provided within the body so as to extend over at least a region of the latter. An inlet (32) is provided in the body (20) in communication with the passage therein. The inlet (32) enables a rigidifying material to be introduced into the passage (28) in the body (20) so that at least the region of the body (20) in which the passage is provided can be rigidified whereby to maintain the body in its expanded condition.