An apparatus (10) is provided for implantation into an adjacent pair of vertebral bodies (12 and 14) having first and second surfaces (17 and 19) that oppose each other. The apparatus (10), when implanted, is attached to the adjacent pair of vertebral bodies and stabilizes the vertebral bodies (12 and 14) while the vertebral bodies fuse together. The apparatus (10) comprises a platform (24) having a third surface (38) extending transverse to the first and second surfaces (17 and 19). The apparatus (10) further comprises at least one helical spike (50, 52) for embedding into each of the adjacent pair of vertebral bodies (12 and 14) upon rotation of the platform (24) to attach the helical spike to each of the vertebral bodies and thus fasten the vertebral bodies together. The helical spike (50, 52) projects from the platform (24) and extends around a longitudinal axis (22). The helical spike (50, 52) has a tip portion (58) at a distal end (62) for penetrating the first and second surfaces (17 and 19) and for screwing into the adjacent pair of vertebral bodies (12 and 14) as the platform (24) is rotated. The helical spike (50, 52) at least partially defines an internal cavity (140) for receiving material (130) that promotes fusion of the vertebral bodies (12 and 14).