Intervertebral prosthesis
An intervertebral prosthesis for insertion between adjacent vertebrae includes upper and lower prosthesis plates locatable against respective vertebrae and having opposing, concavely curved recesses therein, and a core located between the plates. The core has opposed, convexly curved surfaces received in the recesses of the plates to allow the plates to slide in articulated manner over the core. The opposed surfaces of the core and the recesses of the plates have cooperating spherical curvatures. The recess of each plate surrounds a locating peg projecting centrally from the base of the recess and is bounded by an annular rim, such that the annular rims of the plates are arranged to contact one another at a predetermined limit of sliding movement of the plates over the core. The peg locates loosely in an opening located centrally in a curved surface of the core, whereby the plates can slide over the core in all directions while the peg holds the core captive.
1. A system for insertion of an intervertebral prosthesis between adjacent vertebrae, the system comprising:
a first prosthesis plate comprising a major surface to engage the first vertebra and a cooperating surface disposed opposite the major surface;
a second prosthesis plate comprising a major surface to engage the second vertebra and a cooperating surface disposed opposite the major surface, wherein the cooperating surfaces of the first and second plates are arranged to cooperate to form an articulate joint;
a first annular rim disposed around the cooperating surface of the first plate and protruding outward from the first plate toward the second plate, the first rim having a peripheral groove formed thereon;
wherein the groove is adapted to facilitate manipulation and holding of the prosthesis with an appropriate instrument while the prosthesis is placed in the intervertebral space; and
an instrument for placing the intervertebral disc, the instrument configured to hold the prosthesis at the peripheral groove.
2. The system according to claim 1 , wherein the cooperating surfaces are spherical.
3. The system according to claim 1 , wherein the annular rim bounds the cooperating surface.
4. The system according to claim 1 , wherein the plates are spaced apart.
5. The system according to claim 1 , wherein the groove is disposed adjacent the plate.
6. The system according to claim 1 , wherein the first plate comprises an outer boundary having a distance across and the second plate comprises an outer boundary having a distance across, wherein a distance across the rim is less than the distance across the outer boundary of each plate.
7. The system according to claim 1 , further comprising a second annular rim disposed around the cooperating surface of the second plate and protruding outward from the second plate toward the first plate.
8. The system according to claim 7 , wherein the second annular rim of the second plate bounds the cooperating surface of the second plate.
9. The system according to claim 8 , wherein the second rim has a peripheral groove formed thereon, the peripheral grooves adapted to facilitate manipulation and holding with the instrument while the prosthesis is placed in the intervertebral space.
10. The system according to claim 9 , wherein the plates are spaced apart.
11. The system according to claim 1 , further comprising a core located between the plates, the core comprising a first surface adapted to engage the cooperating surface of the first plate and a second surface adapted to engage the cooperating surface of the second plate, wherein the first surface of the core and the cooperating surface of the first plate comprise cooperating spherical surfaces.
12. The system according to claim 11 , wherein the second surface of the core and the cooperating surface of the second plate comprise cooperating spherical surfaces.
13. The system according to claim 12 , wherein the spherical cooperating surfaces of the plates are concavely curved and the first and second spherical surfaces of the core are convexly curved.
14. The system according to claim 1 , wherein the annular rims are arranged to contact one another at a predetermined limit of articulate movement of the plates.
15. The system according to claim 1 , wherein the peripheral groove is an annular groove.
16. The system according to claim 9 , wherein the peripheral grove on the second plate is an annular grove.