An intervertebral disk prosthesis in a preferred embodiment has a matrix of bioincorporable fabric, and a nuclear core centrally mixed into the matrix. The core is formed by impregnating the fabric substrate centrally with a polymer, preferably of liquid form that cures into a viscoelastic solid, in which each component--polymer and fabric--reinforces the other against tearing, shearing and weakening under stress. The core is a hybrid composite adapted for elastic deformation centrally of the matrix, in which the polymer is mixed with the fabric, and is surrounded by the outer bioincorporable fabric margin of the matrix. In another embodiment, the nuclear core is separated from an outer sheath of the bioincorporable fabric by an intermediate ligament encasement that surrounds the purely polymeric core In either embodiment, each edge of the outer fabric that interfaces a vertebral end plate is impregnated with an agent to stimulate osseus incorporation and anchoring. An adjunct anchoring system with penetration of bone of adjacent vertebra may be used to for attachment until and after bioincorporation occurs.