A method and apparatus is provided for use in spinal fusion procedures. A one or two piece interbody fusion device has a fusion bearing component designed to bear the axial loading from the end plates of adjacent vertebrae. An optional retention piece prevents migration of the load bearing device. One or more fasteners secure the retention device to the vertebrae above and below the load bearing device. The fasteners cause the end plates of the vertebrae to compress the end plates to the load bearing device to facilitate proper fusion. An anti-backout mechanism prevents the fasteners backing out.
