Spinal cage having deployable member
A spinal cage with a wall extending in a longitudinal direction defining an interior space is disclosed. There is also provided a deployable element in movable relation to the spinal cage. In some embodiments, there is a rib, and the rotatable member is engaged at one end with the wall and at the other end with the rib. In some embodiments, the spinal cage is provided with holes for screws that can be directed at adjacent vertebrae for fixation. Such a spinal cage can be used with the spin-plate or with the screws. The screws and the spinal cage may have features that cooperate to prevent back-out of the screws.
1. A spinal cage assembly, comprising:
a spinal cage having a structure suitable to maintain two vertebrae separate from each other and having an interior having at least some empty space defined by an internal surface,
said spinal cage having at least one screw hole suitable to receive a bone screw directed through an external surface of said spinal cage and having a screw hole axis aimed, in a direction along said screw hole from an exterior of said spinal cage toward said interior of said spinal cage, so as to point partially away from said spinal cage in a longitudinal direction;
a spin-plate engageable with said spinal cage and rotatable with respect to said spinal cage, wherein when said spin-plate is in an undeployed position, said spin-plate covers at least a portion of said screw hole, and when said spin-plate is in a deployed position, said spin-plate covers none of said screw hole or less of said screw hole than when said spin-plate is in said undeployed position; and
wherein said spinal cage comprises a first feature suitable to receive a first end of a shaft of said spin-plate and comprises a second feature suitable to receive a second end of said shaft of said spin-plate, wherein said first feature is a first internal groove within said internal surface and said second feature is a second internal groove within said internal surface, said second internal groove being opposed to said first internal groove.
2. The spinal cage assembly of claim 1 , wherein said spinal cage comprises an internal circumferential groove in said spinal cage going circumferentially around an interior of said screw hole.
3. The spinal cage assembly of claim 2 , further comprising a bone screw with a head having a snap-ring engaged around said head, said snap-ring being engageable in said internal circumferential groove.
4. The spinal cage assembly of claim 3 , wherein said snap-ring when engaged with said bone screw has a leading external corner that is rounded and a trailing external corner that is sharper than said leading external corner.
5. The spinal cage assembly of claim 1 ,
wherein when said spin-plate is in said deployed position, said spin-plate covers none of said screw hole.
6. The spinal cage assembly of claim 1 , wherein said screw hole axis is aimed partially toward a midplane of said spinal cage with respect to a medial-lateral direction of said spinal cage.
7. The spinal cage assembly of claim 1 , further comprising a locking feature for locking a bone screw in said screw hole.
8. The spinal cage assembly of claim 7 , wherein said locking feature comprises an internal circumferential groove in said spinal cage going circumferentially around an interior of said screw hole.
9. The spinal cage assembly of claim 1 , wherein said screw hole comprises internal threads.
10. The spinal cage assembly of claim 1 , wherein said spinal cage comprises two of said screw holes, and wherein, proceeding from said exterior towards said interior of said spinal cage, a first axis of a first of said screw holes points superiorly of said spinal cage and a second axis of a second of said screw holes points inferiorly of said spinal cage.
11. The spinal cage assembly of claim 1 , wherein said spinal cage comprises two of said screw holes, and wherein, proceeding from said exterior towards said interior of said spinal cage, a first axis of a first of said screw holes points toward a vertical midplane of said spinal cage and a second axis of a second of said screw holes points toward said vertical midplane of said spinal cage.
12. The spinal cage assembly of claim 11 , wherein, when viewed along said longitudinal direction of said spinal cage, each one of said first axis and said second axis intersects at a common place on said vertical midplane.
13. The spinal cage assembly of claim 1 , further comprising a bone screw, wherein said spinal cage has an anterior portion and a posterior portion opposed to said anterior portion, and said bone screw enters through an anterior surface of said spinal cage and proceeds posteriorly, and wherein when viewed along said longitudinal direction of said spinal cage, a posterior end of said bone screw in a final assembled position overlaps said posterior portion of said spinal cage.
14. A kit comprising the spinal cage of claim 1 , and a bone screw, and said spin-plate, wherein said spinal cage is suitable to be implanted in a patient alone, or with said spin-plate assembled to said spinal cage, or with said bone screw in said screw hole, or with both said spin-plate assembled to said spinal cage and said bone screw in said screw hole.
15. A spinal cage comprising:
a wall having an internal surface and an external surface, both extending vertically and generally parallel to a vertical axis of said spinal cage and progressing circumferentially, wherein said external surface forms a closed circumference, and wherein said internal surface forms a closed perimeter defining an interior space;
wherein said internal surface comprises at least a first internal groove within said internal surface, said groove extending vertically at least approximately parallel to said vertical axis;
wherein said first internal groove has two respective side walls opposed to each other and generally parallel to each other, said two respective side walls defining a groove width therebetween, said first internal groove having a groove base surface connecting between said side walls;
wherein at a first vertical end of said first internal groove, said side walls extend as far as said wall extends vertically;
wherein at an opposed vertical end of said first internal groove, said side walls connect with a curved surface within said internal surface, said curved surface defining a cylindrical space within said internal surface having a cylindrical diameter;
wherein said cylindrical diameter is greater than said groove width and said cylindrical space is centered midway between said side walls; and
at least one screw hole suitable to receive a bone screw directed through said external surface of said wall and having a screw hole axis aimed, in a direction along said screw hole from an exterior of said spinal cage toward said interior space of said spinal cage, so as to point partially away from said spinal cage in a longitudinal direction.
16. The spinal cage of claim 15 further comprising a second internal groove.
17. The spinal cage of claim 16 wherein said second internal groove has a second groove width, and said first groove width is unequal to said second groove width.
18. The spinal cage of claim 15 further comprising a spin-plate engaging at least said first internal groove.
19. The spinal cage of claim 15 further comprising at least one bone screw.
20. The spinal cage assembly of claim 1 , wherein when said spin-plate is in said deployed position, said spin-plate covers less of said screw hole than when said spin-plate is in said undeployed position.