Patent ID: 7771475

Claim:
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, said spinal implant comprising: a housing having a leading end for insertion first into the disc space, a trailing end opposite said leading end, a mid-longitudinal axis between said leading end and said trailing end of said housing, an upper surface adapted to contact one of the adjacent vertebral bodies, a lower surface opposite said upper surface adapted to contact another one of the adjacent vertebral bodies, and a hollow interior configured to hold bone growth promoting material therein, said hollow interior being between said upper and lower surfaces and said leading and trailing ends, said housing having a horizontal plane parallel to the mid-longitudinal axis passing through said leading end and trailing end of said housing, the horizontal plane bisecting said housing into two equal parts, said upper and lower surfaces each having at least one opening therein in communication with said hollow interior and with each other to permit for the growth of bone from adjacent vertebral body to adjacent vertebral body through said hollow interior of said housing; at least two internal rotatable members positioned at least in part within said hollow interior of said housing, a first of said rotatable members being proximate to said upper surface, a second of said rotatable members being proximate to said lower surface, each of said rotatable members having a longitudinal axis and a maximum cross-sectional dimension transverse to the longitudinal axis; and a plurality of bone engaging projections each having a base extending from each of said rotatable members and terminating at an end, said bone engaging projections adapted to penetrably engage the bone of the adjacent vertebral bodies by rotating about the longitudinal axes of said rotatable members, respectively, each of said bone engaging projections having a dimension as measured in a direction transverse to the longitudinal axes of each of said rotatable members, respectively, from said base to said end being greater than the maximum cross-sectional dimension of each of said rotatable members, said bone engaging projections being adapted to rotate within said hollow interior of said housing between a retracted position and a deployed position, at least a portion of one of said bone engaging projections being within said hollow interior of said housing when in the retracted position, said bone engaging projections of said rotatable members extending through said one of said upper and lower surfaces of said housing so as to penetrably engage the bone of the adjacent vertebral bodies when in the deployed position, said hollow interior being unobstructed by said bone engaging projections when in the deployed position to permit for the growth of bone from adjacent vertebral body to adjacent vertebral body through said hollow interior.