Patent ID: 7270680
Filing Date: 2007-09-18
Classification: A61F

Abstract:
1. An intervertebral spacer device comprising: first and second plate members, each having inner and outer plate surfaces, said plate members being disposed in a spaced apart relationship such that the inner surfaces of said plates oppose one another, and the outer surfaces of said plates face in opposite directions; and at least one restoring force providing element disposed between the first surfaces of said first and second plate members, and disposed such that a compressive load applied to the second surfaces of said plate members is counteracted by said at least one restoring force providing element, said at least one restoring force providing element including at least one belleville washer having at least one radially extending groove and at least one spiral slot, wherein said at least one radially extending groove in said at least one belleville washer comprises a plurality of spaced apart radially extending grooves, each of which has a depth that tapers along said length, and a width that tapers along said length that extends from a locus on a peripheral edge of said at least one belleville washer to a locus which is radially in from said peripheral edge.