US Patent 7771475 Spinal implant having deployable bone engaging projections

Instrumentation is disclosed for inserting an interbody spinal fusion implant for implantation at least in part within and across the generally restored height of a disc space between two adjacent vertebral bodies of a human spine. The implant has an external housing and a substantially hollow internal rotatable member having bone engaging projections that are deployable through the housing to penetrably engage the adjacent vertebral bodies.