Spinal implant

A combination insertion tool and implant for fusing two opposing vertebra each having opposing end plates of cortical bone and vertebra interior of cancellous bone and wherein said opposing end plates are separated by a disc space, said combination comprising:

• a. an implant having:
• 1. at least four generally linear thread segments;
• 2. rigid supports for holding said thread segments in spaced apart alignment with said thread segments defining longitudinal edges of a parallelepiped;
• 3. said thread segments including a plurality of individual threads with said individual threads of said segments defining a thread pattern selected to mate with a thread pattern of said bore;
• 4. said supports and said thread segments defining a hollow implant interior exposed to an exterior of said implant through at least aligned bone-growth openings formed through said implant on opposite sides thereof;
• b. an insertion tool having:
• 1. a distal end including grips sized to extend between opposing thread segments of said implant with at least two of said grips having external threads selected to match said thread pattern;
• 2. a proximal end connected to said distal end through a tool body.

A method for fusing two opposing vertebra each having opposing end plates of cortical bone and vertebra interior of cancellous bone and wherein said opposing end plates are separated by a disc space, said method comprising:

• a. forming a threaded bore into said disc space and at least partially into said cortical bone of said opposing end plates;
• b. selecting an implant having:
• 1. at least four generally linear thread segments;
• 2. rigid supports for holding said thread segments in spaced apart alignment with said thread segments defining longitudinal edges of a parallelepiped;
• 3. said thread segments including a plurality of individual threads with said individual threads of said segments defining a thread pattern selected to mate with a thread pattern of said bore;
• 4. said supports and said thread segments defining a hollow implant interior exposed to an exterior of said implant through at least aligned bone-growth openings formed through said implant on opposite sides thereof;
• c. threading said implant into said bore to a full inserted position with said thread segments in residence in said cortical bone and with said bone-growth openings opposing said cancellous bone of each of said vertebra.