A filamentary occlusion assembly 10 comprises a longitudinal filamentary element 12 of biocompatible material, such as small intestine submucosa, and a pliable radiopaque wire 14 helically wound therearound to provide the filamentary element 12 with rigidity and radiopacity. The wire 14 is wound around the filamentary element 12 to form radiopaque marker regions 16, formed by winding the 10 radiopaque wire 14 with a small pitch, that are separated by spacer sections 18 where the radiopaque wire 14 is coiled with a much greater pitch. The marker 16 and spacer 18 regions being interposed between one another in series along the length of the filamentary element 12. A winding apparatus 30 for winding wire 14 around a filamentary element 12 is also taught and comprises both a carrier, such as a spool 34, for holding the wire 12, and a feed member 32 provided with a lumen through which the filamentary element 12 may pass. The carrier 34 being attached to, and rotable with respect to, the feed member 32. A method of forming an occlusion assembly is also disclosed.
