which has a diameter of 60 mu m a polymer thread or a thread made of a nickel titanium alloy extends through the inner hollow space of the micro helix with said thread being fixed at the proximal and distal end of the helix 9 and prevents the helix 9 from being torn off during the placement or repositioning on the platinum iridium wire an elastic biasing force has been imprinted which forces it into its preformed tetrahedral configuration as soon as the mechanical constraint caused by the catheter has been omitted although the platinum iridium alloy used has no shape memory properties it greatly improves the slidability of the helix during placement on account of its excellent supporting characteristics fig5 by way of 4 radial sections 10 to 10 u2032 u2033 represents the secondary structure of the tetrahedron shown in fig4 in the form of the development of a ball the loops 7 8 themselves are of roughly circular shape and having assumed their predetermined spatial configuration form a regular tetrahedron along the longitudinal axis of helix 9 the large 7 and the small loops 8 are arranged alternately with the small loops 8 being placed between the large loops 7 the proximal and the distal ends of helix 9 are identified by reference number 11 and respectively 12 in fig6 an implant 1 u2032 according to the invention is illustrated that is placed into an aciniform aneurysm 13 said implant forming into a tetrahedron 6 as tertiary structure by arranging the smaller loops 8 in the area of the faces 2 u2032 of the tetrahedron 6 built up by the large loops 7 a higher packing density.