a revisable intervertebral implant may include two end plates designed to detachably receive a variety of intermediate components including articulating bearing inserts , elastic inserts , and fusion blocks . each intermediate component may be secured to a snap insert that snaps into engagement with the corresponding end plate in response to pressure urging the intermediate component toward the end plate along a cephalad - caudal direction . the end plates may first be secured to the corresponding vertebral bodies , and then the intermediate component may be snapped into locking engagement with the implanted end plates to complete in - situ assembly of the intervertebral implant . the implant may easily be revised by snapping the intermediate component out of engagement with the end plates , removing the intermediate component , inserting the new intermediate component into the space between the end plates , and snapping the new intermediate component into engagement with the end plates .