A method and apparatus is provided for use in spinal fusion procedures. An interbody fusion device has a first piece that is a load bearing device designed to bear the axial loading from the end plates of adjacent vertebrae. A second piece of the interbody fusion device is a retention component whose primary functions are to prevent migration of the load bearing device and loss or migration of graft material from within the load bearing device. A secondary function of the retention component is to address fixation of fasteners when the surgeon is confronted with a challenging access to adequate boney structures due to excessive curvature/angulation of the vertebrae column, minimal invasive surgery techniques, danger to surrounding vascular or neurological tissues, poor bone quality, or similar surgical complications. A tertiary function of the retention component is to provide better alignment and stabilization of misaligned vertebrae when spondylolisthesis is a significant factor. One or more fasteners secure the retention component to each of 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.
