Patent ID: 8535378

Claim:
An interbody spacer adapted for placement between a pair of spaced and facing vertebrae of a spine; said spacer comprising: a) a body having upper and lower abutment surfaces adapted to engage respective vertebrae during use and a front surface and a rear surface; said front and rear surfaces having substantially equal widths and being substantially flat and vertically aligned in use; said upper and lower abutment surfaces being generally convex from front to rear formed by a front planar facet, a middle planar facet, and a rear planar facet, wherein the middle planar facet includes opposed planar lateral bevels sloping outwardly wherein said abutment surfaces have a maximum height at a point closer to a body midline than to both said front and rear surfaces so as to be adapted to conform to the curvature of facing surfaces of the vertebrae and so as to facilitate insertion; b) said body having a pair of opposed concave lateral side surfaces that extend from the front to the rear thereof and include at least one tool-engagement formation wherein each of said side surfaces cooperate with said planar lateral bevels so as to facilitate rotation of the spacer during installation; and c) a first width of a first intersection of said front surface with each of the upper and lower abutment surfaces being substantially equal to a second width of a second intersection of said rear surface with each of the upper and lower abutment surfaces so as to resist subsidence of said body into the facing surfaces of the vertebrae; a third width of each of the upper and lower abutment surfaces being greater than the first and second widths at a location spaced from both the first and second intersections; and d) said body having a solid core located between said side surfaces.