A vena cava filter 40 includes a plurality of filter legs with distal ends 50 having tips 52. The tips curve outwardly and end in a part spherical bulbous head element 54. A biodegradable barb 56 is attached to the enlarged head 54 such that after degradation the enlarged head element 54 is left embedded in the vessel wall 60. The degradation of the barb 56 helps to prevent further penetration of the distal end 50 of the filter legs 44 into the vessel wall 60 and reduces the risk of piercing the vessel wall 60. The enlarged head 54 also ensures that the distal ends 50 of the filter legs 44 remain attached to the vessel wall 60 to ensure correct long term placement. The barb 56 may be formed over the enlarged head 54, or may have a protrusion that extends into a fixation recess on the enlarged head 54.