PROSTHETIC DISC FOR INTERVERTEBRAL INSERTION

• US 20160250035A1
• Filed: 05/10/2016
• Published: 09/01/2016
• Est. Priority Date: 05/27/2003
• Status: Active Grant

• Current Assignee: Simplify Medical Pty. Ltd. (Nuvasive Incorporated)
• Original Assignee: Simplify Medical PTD Limited
• Inventors: de Villiers, Malan, Hahnle, Ulrich
• Granted Patent: US 9,655,741 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: A61F 2/442 Intervertebral or spinal discs, e.g. resilient non-disc-shaped intervertebral inflatable pockets A61F2/441; non-disc-shaped intervertebral fusion implants A61F2/4455
• CPC Class Codes: A61F 2/4425 made of articulated components
• CPC Class Codes: A61F 2002/3008 radio-opaque, e.g. radio-opaque markers
• CPC Class Codes: A61F 2002/30131 horseshoe- or crescent- or C-shaped or U-shaped
• CPC Class Codes: A61F 2002/30245 Partial spheres
• CPC Class Codes: A61F 2002/30299 umbrella-shaped or mushroom-shaped
• CPC Class Codes: A61F 2002/30518 with possibility of relative movement between the prosthetic parts
• CPC Class Codes: A61F 2002/30649 Ball-and-socket joints
• CPC Class Codes: A61F 2002/30785 parallel
• CPC Class Codes: A61F 2002/30822 Circumferential grooves
• CPC Class Codes: A61F 2002/30838 Microstructures
• CPC Class Codes: A61F 2002/30884 Fins or wings, e.g. longitudinal wings for preventing rotation within the bone cavity
• CPC Class Codes: A61F 2002/30904 serrated profile, i.e. saw-toothed
• CPC Class Codes: A61F 2002/443 having two transversal endplates and at least one intermediate component
• CPC Class Codes: A61F 2002/5098 with rotation-limiting means
• CPC Class Codes: A61F 2230/0076 ellipsoidal or ovoid
• CPC Class Codes: A61F 2310/00179 Ceramics or ceramic-like structures

Abstract

A prosthetic disc for insertion between adjacent vertebrae includes a core having upper and lower curved surfaces, upper and lower plates, and peripheral restraining structure on at least one of the upper plate, the lower plate and the core. Each plate has an outer surface which engages a vertebra and an inner curved surface which slides over the curved surface of the core. The peripheral restraining structure serves to hold the core against a curved surface of at least one of the plates during sliding movement of the plates over the core.

Claims

1. A prosthetic disc for insertion between adjacent vertebrae, the prosthetic disc comprising:

a first plate having a first surface configured to engage a vertebra and an opposite inwardly directed bearing surface;

a second plate having a second surface configured to engage a vertebra and an opposite inwardly directed bearing surface;

a rigid mobile core having first and second bearing surfaces configured to cooperate with the bearing surfaces of the first and second plates to allow the first and second plates to slide and translate over the core; and

a retaining formation which holds the core captive between the first and second plates;

wherein the retaining formation includes two or more recesses circumferentially spaced apart about the periphery of the core and two or more inwardly directed pegs on the first plate each peg opposing a circumferentially spaced recess.

2. A prosthetic disc as in claim 1, wherein at least one of the first and second bearing surfaces of the core is spherical.

3. A prosthetic disc as in claim 2, wherein both of the first and second bearing surfaces of the core are spherical.

4. A prosthetic disc as in claim 1, wherein the retaining formation defines a stop structure to limit relative inclination of the plates during sliding movement of the plates over the core.

5. A prosthetic disc as in claim 1, wherein the retaining formation allows anterior, posterior and lateral motion of the core with respect to the first and second plates.

6. A prosthetic disc as in claim 1, wherein the core has a substantially circular perimeter.

7. A prosthetic disc as in claim 1, wherein the pegs extend into the recesses.

8. A method of retaining a core in a prosthetic disc, the method comprising:

providing a first plate having a first surface which engages a vertebra and an opposite bearing surface;

providing a second plate having a second surface which engages a vertebra and an opposite bearing surface;

providing a rigid mobile core between the first and second plates, the core having first and second bearing surfaces configured to cooperate with the bearing surfaces of the first and second plates to allow the first and second plates to slide and translate over the core;

providing a retaining formation including two or more recesses circumferentially spaced apart about the periphery of the core and two or more inwardly directed pegs on the first plate each peg opposing a circumferentially spaced recess; and

retaining the core between the first and second plates with the retaining formation.

9. A method as in claim 8, wherein the pegs extend into the recesses during sliding motion of the plates over the core.

10. A method as in claim 8, wherein the core includes at least one spherical bearing surface.

11. A method as in claim 8, wherein the core has a substantially circular perimeter.

12. A method as in claim 8, wherein the method allows anterior, posterior and lateral motion of the core with respect to the first plate.

13. A method as in claim 8, wherein the method allows anterior, posterior and lateral motion of the core with respect to the second plate.