Intervertebral prosthetic disc

An intervertebral prosthetic disc assembly comprised of substantially rigid, bio-compatible material, said assembly comprising in combination a disc and a separate vertebral attachment member, said disc comprising a base plate member adapted to be secured to a first vertebra and a convex surface having a non-central maximum vertical dimension, a non-central vertical axis along the line of maximum vertical dimension, an anterior-posterior axis passing through said non-central vertical axis, and where said convex surface is non-spherical in a vertical plane containing said anterior-posterior axis;

• said vertebral attachment member comprising a base plate member adapted to be secured to a second vertebra and a concave surface corresponding to said convex surface, such that said concave surface generally mates with said convex surface therein to allow for relative sliding or rotational movement therebetween.

An intervertebral prosthetic disc composed of a substantially rigid, bio-compatible material, said disc having a pair of opposing convex surfaces, said convex surfaces being an inferior surface and a superior surface, a non-central vertical axis at the point of maximum vertical dimension between said inferior surface and said superior surface, an anterior-posterior axis, a central vertical axis at the midpoint of said anterior-posterior axis, said non-central vertical axis and said vertical axis passing through said anterior-posterior axis, where said superior convex surface is joined to said inferior convex surface by a generally vertically disposed wall member, where the junction between said wall member and said superior convex surface defines a first plane and where the junction between said wall member and said inferior convex surface defines a second plane, and where said first plane and said second plane are non-parallel and where said superior convex surface contacts said inferior convex surface.

An intervertebral prosthetic disc composed of a substantially rigid, bio-compatible material, said disc having a pair of opposing convex surfaces, said convex surfaces being an inferior surface and a superior surface, a non-central vertical axis at the point of maximum vertical dimension between said inferior surface and said superior surface, an anterior-posterior axis, a central vertical axis at the midpoint of said anterior-posterior axis, said non-central vertical axis and said vertical axis passing through said anterior-posterior axis, where said superior convex surface is joined to said inferior convex surface by a generally vertically disposed wall member, where the junction between said wall member and said superior convex surface defines a first plane and where the junction between said wall member and said inferior convex surface defines a second plane, and where said first plane and said second plane are non-parallel and where said superior convex surface and said inferior convex surface are each sections of a sphere.

An intervertebral prosthetic disc for placement between two adjacent vertebrae, said disc consisting of a substantially rigid, non-porous, bio-compatible material, said disc having a pair of opposing convex surfaces, said convex surfaces being an inferior surface and a superior surface, a non-central vertical axis at the point of maximum vertical dimension between said inferior surface and said superior surface, an anterior-posterior axis, a central vertical axis at the midpoint of said anterior-posterior axis, said non-central vertical axis and said vertical axis passing through said anterior-posterior axis, where said convex surfaces are not fixed to said adjacent vertebrae such that said disc has free movement relative to said adjacent vertebrae.