A bag for use in the intravascular treatment of saccular aneurysms and a method of forming the bag are disclosed. The bag is formed from a plurality of flexible, resilient filamentary members braided into a tubular sleeve and biased into a first shape having an expanded first
diameter sized to substantially fill the
aneurysm. The bag is resiliently deformable into a second shape having a
diameter smaller than the first and sized to slidingly interfit within the lumen of a
catheter. An opening is provided in the bag to receive a clotting medium, such as a
platinum wire, on which blood clots can be induced to form by mechanical or electrolytic means. A closure is provided by biasing the filamentary members to form a
constriction around the opening. In use the, bag is inserted into a saccular
aneurysm via the
catheter and expands to its first
diameter upon release therefrom. Interstices between the interbraided filamentary members provide pores allowing blood from the
aneurysm to enter the bag when the bag is positioned within the aneurysm. The clotting medium wire is packed into the bag, blood clots on the wire and occludes the aneurysm, sealing it off from the
blood stream and preventing rupture. The wire is released from the
catheter and is contained within the bag in the aneurysm.