Intervertebral prosthesis

Patent metadata

Field	Value
Publication number	US-9839525-B2
Application number	US-201615284344-A
Country	US
Kind code	B2
Filing date	Oct 3, 2016
Priority date	Sep 19, 2002
Publication date	Dec 12, 2017
Grant date	Dec 12, 2017

Abstract

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.

First claim

What is claimed is:

1. A method comprising:
providing a prosthesis comprising:
upper and lower prosthesis plates each having an upstanding elongate projection, wherein the upstanding elongate projections are elongated in an anterior/posterior direction, the upper prosthesis plate having a concavely curved, spherical bearing surface therein;
a moveable core having a convexly curved, spherical surface configured to cooperate with the concavely curved surface of the upper plate, wherein the upper and lower plates are able to both translate and rotate with respect to each other and with respect to the core, and
a protrusion on at least one of the plates and a corresponding opening on the core, wherein the protrusion holds the core captive and prevents the core from slipping out sideways from between the plates, and
wherein the protrusion is present on one of the upper and lower plates and not on the other plate; and

implanting the prosthesis between adjacent vertebrae.

2. The method according to claim 1 , wherein a maximum articulation between the upper and lower plates after implantation is 12 degrees.

3. The method according to claim 1 , wherein the protrusion and the corresponding opening are located at a center of the at least one plate and a center of the movable core, respectively.

4. The method according to claim 1 , wherein the upstanding elongate projections each include a plurality of holes formed transversely through the projections.

5. The method according to claim 1 , wherein the plates have coarse surfaces adjacent to the projection, the coarse surfaces comprising machined serrated finishes.

6. The method according to claim 1 , wherein the lower plate has a concavely curved, spherical bearing surface therein which is opposed to the concavely curved surface of the upper plate.

7. The method according to claim 1 , wherein a radius of curvature of the bearing surface is about 18 mm.

8. The method according to claim 1 , wherein the concavely curved, spherical bearing surface of the upper plate is bounded by an annular rim.

9. The method according to claim 8 , wherein the lower plate is bounded by an annular rim, and wherein the annular rims contact one another at a limit of articulation of the plates.

10. The method according to claim 1 , wherein the upstanding elongate projections each have a height larger than a width.

11. The method according to claim 1 , wherein the upstanding elongate projections each have a length longer than a width.

12. The method according to claim 1 , wherein the upstanding elongate projections are each substantially centered between opposite lateral edges of the plate.

13. The method according to claim 1 , wherein the protrusion comprises a peg carried by the lower prosthesis plate and the core is held captive by the action of the peg.

14. The method according to claim 13 , wherein the movable core includes a passage for receiving the peg.

15. The method according to claim 14 , wherein a transverse dimension of the peg at all points along a length of the peg is less than a transverse dimension of the passage to allow the plate to slide over the core.

16. The method according to claim 1 , wherein the upstanding elongate projections are each placed in a slot cut in the associated vertebral surface.

17. The method according to claim 1 , wherein the adjacent vertebrae are forcibly separated from one another to provide the necessary space for insertion of the prosthesis.

18. The method according to claim 1 , wherein the protrusion is in the form of a peg.

19. The method according to claim 1 , wherein the lower prosthesis plate has a flat lower surface and the upstanding elongate projection extends in the anterior/posterior direction from the flat lower surface.

20. The method according to claim 1 , wherein the upper prosthesis plate has a flat upper surface and the upstanding elongate projection extends in the anterior/posterior direction from the flat upper surface.

21. A method comprising:
providing a prosthesis comprising:
upper and lower prosthesis plates each having a bone contacting surface with at least one of the upper and lower prosthesis plates having an upstanding elongate projection, wherein the upstanding elongate projection is elongated in an anterior/posterior direction, the upper prosthesis plate having a concavely curved, spherical bearing surface therein, without any protrusions extending from the spherical bearing surface;
a moveable core having a convexly curved, spherical surface configured to cooperate with the concavely curved surface of the upper plate, wherein the upper and lower plates are able to both translate and rotate with respect to each other and with respect to the core, and
a protrusion on a bearing surface of the lower prosthesis plate and a corresponding opening on the core, wherein the protrusion holds the core captive and prevents the core from slipping out sideways from between the plates; and

implanting the prosthesis between adjacent vertebrae.

22. The method according to claim 21 , wherein the protrusion is in the form of a peg.

Assignees

• Simplify Medical Pty Ltd

Inventors

• De Villiers Malan
• Hahnle Ulrich

Classifications

• A61F2002/302

  toroidal, e.g. rings · CPC title

• A61F2/4611

  of spinal prostheses · CPC title

• A61F2002/30662

  with rotation-limiting means · CPC title

• A61F2002/30899

  Protrusions pierced with apertures · CPC title

• A61F2002/30364

  Rotation about the common longitudinal axis · CPC title