Modular intervertebral disc replacements

• US 20070185578A1
• Filed: 02/03/2006
• Published: 08/09/2007
• Est. Priority Date: 02/03/2006
• Status: Active Grant

• Current Assignee: Depuy Spine Incorporated (Johnson & Johnson)
• Original Assignee: Depuy Spine Incorporated (Johnson & Johnson)
• Inventors: Sutton, Jeffrey, Dooris, Andrew, O'Neil, Michael
• Granted Patent: US 7,708,777 B2
• Time in Patent Office: Days
• US Class Current: 623/17.140
• CPC Class Codes: A61F 2/4425 made of articulated components
• CPC Class Codes: A61F 2002/30332 Conically- or frustoconically-shaped protrusion and recess
• CPC Class Codes: A61F 2002/30354 Cylindrically-shaped protrusion and recess, e.g. cylinder of circular basis
• CPC Class Codes: A61F 2002/30364 Rotation about the common longitudinal axis
• CPC Class Codes: A61F 2002/30383 made by laterally inserting a protrusion, e.g. a rib into a complementarily-shaped groove
• CPC Class Codes: A61F 2002/30426 Bayonet coupling
• CPC Class Codes: A61F 2002/305 Snap connection
• CPC Class Codes: A61F 2002/30507 using a threaded locking member, e.g. a locking screw or a set screw
• CPC Class Codes: A61F 2002/30604 modular
• CPC Class Codes: A61F 2002/30616 Sets comprising a plurality of prosthetic parts of different sizes or orientations
• CPC Class Codes: A61F 2002/30662 with rotation-limiting means
• CPC Class Codes: A61F 2002/30663 multiaxial, e.g. biaxial; multipolar, e.g. bipolar or having an intermediate shell articulating between the ball and the socket
• CPC Class Codes: A61F 2002/443 having two transversal endplates and at least one intermediate component
• CPC Class Codes: A61F 2220/0025 Connections or couplings between prosthetic parts, e.g. between modular parts; Connecting elements
• CPC Class Codes: A61F 2220/0033 made by longitudinally pushing a protrusion into a complementary-shaped recess, e.g. held by friction fit
• CPC Class Codes: A61F 2310/00407 Coating made of titanium or of Ti-based alloys
• CPC Class Codes: A61F 2310/00796 Coating or prosthesis-covering structure made of a phosphorus-containing compound, e.g. hydroxy(l)apatite

Abstract

A modular disc prosthesis system is provided that allows a disc prosthesis to be constructed, either pre- or intra-operatively, to have a desired degree of freedom or constraint when positioned between endplates of adjacent vertebrae. In particular, the components can be assembled to form a disc prosthesis having a center of rotation that is constrained or fixed such that, when the disc prosthesis is implanted between endplates of adjacent vertebrae, the adjacent vertebrae have one degree of freedom and move about a fixed center of rotation. Alternatively, one or more of the same components and one or more additional components of the system can be used to construct a disc prosthesis having a center of rotation that is unconstrained or that floats such that, when the disc prosthesis is implanted between the endplates of adjacent vertebrae, the adjacent vertebrae have multiple degrees of freedom and can move about a floating or moving center of rotation, i.e., a center of rotation that is not fixed.

Claims

1. A modular intervertebral disc prosthesis system, comprising:

a core component and a plurality of interchangeable components adapted to movably couple to the core component, at least one of the plurality of interchangeable components being configured to movably couple to the core component to form a disc prosthesis having a fixed center of rotation, and at least another one of the plurality of interchangeable components being configured to movably couple to the core component to form a disc prosthesis having a floating center of rotation.

2. The system of claim 1, wherein the core component comprises a first endplate component adapted to be positioned adjacent to a vertebral endplate.

3. The system of claim 2, wherein the plurality of interchangeable components includes a second endplate component adapted to be positioned adjacent to an endplate of a vertebra, and a plurality of central components adapted to be movably disposed between the first and second endplate components.

4. The system of claim 3, wherein the second endplate component includes a bone-contacting surface adapted to be positioned adjacent to an endplate of a vertebra, and an opposed mating surface adapted to mate to at least one of the plurality of central components.

5. The system of claim 4, wherein the plurality of central components includes

first and second central components adapted to be movably disposed between the first and second endplate components to form a disc prosthesis having a floating center of rotation, the second central component being adapted to mate to the second endplate component, and

a third central component interchangeable with the first and second central components and adapted to be movably disposed between the first and second endplate components to form a disc prosthesis having a fixed center of rotation.

6. The system of claim 5, wherein the first central component includes a first substantially convex surface adapted to be movably seated within a corresponding substantially concave surface formed in the first endplate component, and an opposed substantially convex surface adapted to be movably seated within a corresponding substantially concave surface formed in the second component.

7. The system of claim 5, wherein the second central component and the second endplate component are adapted to mate using a connection selected from the group consisting of a snap-fit, an interference fit, a tongue-and-groove, a post-and-bore, and a press-fit.

8. The system of claim 5, wherein the third central component includes a substantially convex surface adapted to be received within a corresponding substantially concave surface formed in the first endplate component, and an opposed mating surface adapted to mate to a complementary mating surface formed on the second endplate component.

9. The system of claim 8, wherein the third central component and the second endplate component are adapted to mate using a connection selected from the group consisting of a snap-fit, an interference fit, a tongue-and-groove, a post-and-bore, and a press-fit.

10. The system of claim 2, wherein the plurality of interchangeable components includes

a second endplate component and a third endplate component, the second and third endplate components being interchangeable and being adapted to be positioned adjacent to an endplate of a vertebra, and

a plurality of central components adapted to be movably disposed between the first endplate component and one of the second and third endplate components.

11. The system of claim 3, wherein the second endplate component includes a bone-contacting surface adapted to be positioned adjacent to an endplate of a vertebra, and an opposed surface having a substantially convex cavity formed therein, and the third endplate component includes a bone-contacting surface adapted to be positioned adjacent to en endplate of a vertebra, and an opposed mating surface adapted to mate to at least one of the plurality of central components.

12. The system of claim 11, wherein the opposed mating surface on the third endplate component and at least one of the plurality of central components are adapted to mate using a connection selected from the group consisting of a snap-fit, an interference fit, a tongue-and-groove, a post-and-bore, and a press-fit.

13. The system of claim 3, wherein the plurality of central components includes

a first central component adapted to be movably disposed between the first and second endplate components, and

a second central component adapted to be disposed between the first and second components, and adapted to move relative to the first component and to mate to the second component to prevent movement between the second central component and the second endplate component.

14. The system of claim 13, wherein the second central component includes an undercut formed around a perimeter thereof and adapted to receive and engage a corresponding ridge formed on the second endplate component to prevent movement between the second central component and the second endplate component.

15. The system of claim 13, wherein the second central component includes a plurality of protrusions formed thereon and adapted to extend into and engage corresponding bores formed in the second endplate component to prevent movement between the second central component and the second endplate component.

16. The system of claim 13, wherein the second central component is adapted to rotate into a locked position to engage the second endplate component to prevent movement between the second central component and the second endplate component.

17. The system of claim 3, wherein the first and second endplate components each include a bone-contacting surface and an opposed surface having a substantially concave surface formed therein, and wherein the plurality of central components includes

a first central component having opposed substantially convex surfaces adapted to be movably received within the substantially concave cavities formed in the first and second endplate components, and

a second central component having a substantially convex surface adapted to be movably received within the substantially concave surface formed in the first endplate component, and an opposed surface adapted to be received within the substantially concave surface formed in the second component and having a mating element adapted to engage the second component to prevent movement between the second central component and the second endplate component.

18. A modular intervertebral disc prosthesis kit, comprising:

at least three components adapted to couple to one another to form a first disc replacement configured to be disposed between adjacent superior and inferior vertebrae and having a constrained center of rotation, and at least one interchangeable component adapted to replace at least one of the at least three components to form a second disc replacement having an unconstrained center of rotation.

19. The kit of claim 18, wherein the components include:

a first endplate component adapted to be positioned adjacent to a first endplate of a first vertebra;

a second endplate component adapted to be positioned adjacent to a second endplate of an adjacent second vertebra; and

a plurality of cores adapted to be interchangeably disposed between the first and second endplate components to allow a first disc prosthesis to be formed having a constrained center of rotation, and a second disc prosthesis to be formed having unconstrained center of rotation.

20. The kit of claim 19, wherein the plurality of cores includes a first core adapted to be freely movably disposed between the first and second endplate components, and a second core adapted to be disposed between the first and second endplate components and adapted to move freely relative to the first endplate component and to engage the second endplate component to prevent movement between the second core and the second endplate component.

21. The kit of claim 19, wherein the plurality of cores includes

first and second cores adapted to be movably disposed between the first and second endplate components to form a disc prosthesis having an unconstrained center of rotation, and

a third core adapted to be disposed between the first and second endplate components to form a disc prosthesis having a constrained center of rotation.

22. The kit of claim 21, wherein the first core has a post formed thereon for mating with a bore formed in the second endplate component, and a substantially concave surface for seating a complementary substantially convex surface formed on the second core, and the third core has a post formed thereon for mating with a bore formed in the second endplate component, and a substantially convex surface adapted to be movably received within a complementary concave surface formed in the first endplate component.

23. The kit of claim 18, wherein each component includes a first surface and a second, opposed surface, at least one of the surfaces being a mating surface configured to mate with a mating surface formed on another one of the components.