Anterior lumbar interbody fusion cage with locking plate
A spinal fixation assembly is provided including a fusion cage with posterior, anterior, superior, and inferior faces, and a plate having at least one aperture for receiving a bone screw and having a mating element adapted to slidably engage and mate to the anterior face of the fusion cage. The cage is adapted to be positioned between adjacent vertebrae, and the plate is effective to mate to the cage and to receive one or more bone screws to fasten the plate and secure the fusion cage to the adjacent vertebrae.
1. A spinal fixation assembly, comprising:
a fusion cage having posterior, anterior, superior, and inferior faces; and
a plate having at least one aperture for receiving a bone screw and having opposed first an second arms that are adapted to slidably receive the fusion cage therebetween such that the opposed first and second arms engage and mate to the superior and inferior faces of the fusion cage in an anterior-posterior direction.
2. The spinal fixation assembly of claim 1 , wherein the superior and inferior faces of the fusion cage each include an ann-seating recess formed therein for receiving the first and second arms on the plate.
3. The spinal fixation assembly of claim 2 , wherein the arms are flush with the superior and inferior faces when disposed within the arm-seating recesses.
4. A spinal fixation assembly 4 , comprising:
a fusion cage having posterior, anterior, superior, and inferior faces, the superior and inferior faces of the fusion cage each including an arm-seating recess formed therein; and
a plate having at least one aperture for receiving a bone screw and having first and second arms adapted to mate with the arm-receiving recesses formed on the fusion cage with an interference fit to temporarily secure the plate to the fusion cage.
5. The spinal fixation assembly of claim 4 , wherein at least one of the arm-receiving recess and the first and second arms includes at least one protrusion formed thereon and adapted to seat in at least one indentation formed in the other one of the arm-receiving recesses and the first and second arms.
6. The spinal fixation assembly of claim 4 , wherein the first and second arms are flexible.
7. The spinal fixation assembly of claim 1 , wherein the anterior face of the fusion cage includes a central bore formed therein, and the plate includes a central aperture extending therethrough and aligned with the central bore, the central aperture and the central bore being adapted to receive a center screw for mating the plate to the fusion cage.
8. The spinal fixation assembly of claim 1 , wherein the fusion cage includes an intermediate plane that separates the inferior face from the superior face to define an inferior side and a superior side, and wherein the plate defines at least one inferior aperture on the inferior side of the fusion cage and at least one superior aperture on the superior side of the fusion cage.
9. The spinal fixation assembly of claim 8 , wherein each aperture in the plate has a first end and a second, opposed end with a sidewall extending therebetween that defines an inner lumen, the assembly further comprising a split bushing disposed within the inner lumen of each aperture in the plate.
10. The spinal fixation assembly of claim 9 , wherein the sidewall of each aperture is concave and wherein each split bushing includes a convex outer surface.
11. The spinal fixation assembly of claim 10 , wherein each split bushing includes a tapered inner lumen.
12. The spinal fixation assembly of claim 9 , wherein each split bushing includes a shoulder formed therein that abuts a corresponding shoulder formed within each aperture.
13. The spinal fixation assembly of claim 9 , wherein each split bushing includes an inner surface having threads formed thereon that are adapted to mate with corresponding threads formed on a bone screw.
14. The spinal fixation assembly of claim 9 , wherein each aperture includes an anti-rotation mechanism effective to prevent each split bushing from rotating within the aperture.
15. The spinal fixation assembly of claim 14 , wherein the anti-rotation mechanism comprises a raised protrusion adapted to be positioned in a split formed in the split bushing.
16. The spinal fixation assembly of claim 9 , wherein the first end of each aperture has a generally spherical recess formed therein for rotatably seating a head of a bone screw.
17. The spinal fixation assembly of claim 8 , wherein the inferior and superior apertures are disposed in inferior and superior tabs.
18. The spinal fixation assembly of claim 17 , wherein the tabs are angled with respect to the fusion cage in a direction anterior to the anterior face of the fusion cage.
19. The spinal fixation assembly of claim 17 , wherein each tab extends in a plane, and wherein each aperture defines a central axis that extends through the aperture at an angle with respect to the plane of the tab in which the aperture is disposed.
20. The spinal fixation assembly of claim 19 , wherein the angle of the central axis of each aperture is in the range of about 0° to 45°.
21. The spinal fixation assembly of claim 1 , further including a plurality of surface features extending outward from the fusion cage on one of the superior face and the anterior face.
22. The spinal fixation assembly of claim 21 , wherein the surface features are selected from the group consisting of fins, ridges, and teeth.
23. A spinal fixation assembly, comprising:
a fusion cage having posterior, anterior, superior, and inferior faces; and
a plate having at least one aperture for receiving a bone screw and having opposed arms for slidably receiving the fusion cage therebetween and for mating and engaging the plate to the anterior face of the fusion cage in an anterior-posterior direction.
24. The spinal fixation assembly of claim 23 , wherein the superior and inferior faces at fusion cage each include a recess for receiving an arm.