Patent ID: 8545561

Claim:
An intervertebral body spacer device for motion preservation, comprising first and second plates with inner and outer surfaces, said plates being disposed in a spaced apart relationship with the inner surface of the first plate facing the inner surface of the second plate, both inner surfaces being separated by a contacting element, wherein the contacting element comprises a disc including a central bore and wherein said inner surfaces of said first and second plates each form sloping surfaces that meet at a ridgeline, such that the ridgelines are disposed at an angle to one another, facing one another, and wherein the inner surface of at least one or both of the plates is non-planar, the plate having a middle and edges and being thicker towards the middle and thinner at the edges, the inner surface comprising at least two sloping smooth surfaces which meet at the ridgeline, the sloping surfaces are different in their sloping design, including different curvatures or different sloping angles.