A multi-composite disc prosthesis is adapted to be implanted within the
annulus of an evacuated disc nucleus space in a human spine. The disc
prosthesis has a generally solid unitary body with a size and a shape
adapted to be positioned within the annulus of the evacuated disc nucleus
space. The body has an outer portion comprised of a first biomaterial and
an inner portion comprised of a second biomaterial. The second
biomaterial has a compressive modulus that is harder than a compressive
modulus of the first biomaterial and the first and second biomaterials
are chemically or physically bonded to form a multi-composite material
that forms the solid body.