Prosthetic intervertebral discs

• US 20070050032A1
• Filed: 09/01/2005
• Published: 03/01/2007
• Est. Priority Date: 09/01/2005
• Status: Abandoned Application

• Current Assignee: Spinal Kinetics Incorporated (Orthofix Medical Inc.)
• Original Assignee: Spinal Kinetics Incorporated (Orthofix Medical Inc.)
• Inventors: Ashley, John, Robinson, Janine, Gittings, Darin, Reo, Michael, Richman, Roxanne, Chee, Uriel, Wistrom, Elizabeth, Koske, Nicholas
• Application Number:
  US11/218,707
• Publication Number:
  US 20070050032A1
• Time in Patent Office: Days
• US Class Current: 623/17.120
• CPC Class Codes: A61F 2/30742 Bellows or hose-like seals; Sealing membranes A61B17/8808 takes precedence; sealing membranes for retaining bone substitute A61F2/2846
• CPC Class Codes: A61F 2/3094 Designing or manufacturing processes
• 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 2/484 Fluid means, i.e. hydraulic or pneumatic
• CPC Class Codes: A61F 2002/30009 differing in fibre orientations
• CPC Class Codes: A61F 2002/30014 differing in elasticity, stiffness or compressibility
• CPC Class Codes: A61F 2002/30075 swellable, e.g. when wetted
• CPC Class Codes: A61F 2002/30133 kidney-shaped or bean-shaped
• CPC Class Codes: A61F 2002/30168 L-shaped
• CPC Class Codes: A61F 2002/30179 X-shaped
• CPC Class Codes: A61F 2002/30224 cylindrical
• CPC Class Codes: A61F 2002/30331 made by longitudinally pushing a protrusion into a complementarily-shaped recess, e.g. held by friction fit
• CPC Class Codes: A61F 2002/30387 Dovetail connection
• CPC Class Codes: A61F 2002/30462 retained or tied with a rope, string, thread, wire or cable
• CPC Class Codes: A61F 2002/30471 connected by a hinged linkage mechanism, e.g. of the single-bar or multi-bar linkage type
• CPC Class Codes: A61F 2002/305 Snap connection
• CPC Class Codes: A61F 2002/30523 by means of meshing gear teeth
• CPC Class Codes: A61F 2002/3055 for adjusting length
• CPC Class Codes: A61F 2002/30563 having elastic means or damping means, different from springs, e.g. including an elastomeric core or shock absorbers
• CPC Class Codes: A61F 2002/30566 : Helical springs
• CPC Class Codes: A61F 2002/30576 : with extending fixation tabs
• CPC Class Codes: A61F 2002/30579 : with mechanically expandable devices, e.g. fixation devices
• CPC Class Codes: A61F 2002/30581 : having a pocket filled with fluid, e.g. liquid
• CPC Class Codes: A61F 2002/30586 : having two or more inflatable pockets or chambers
• CPC Class Codes: A61F 2002/30594 : slotted, e.g. radial or meridian slot ending in a polar aperture, non-polar slots, horizontal or arcuate slots
• CPC Class Codes: A61F 2002/30662 : with rotation-limiting means
• CPC Class Codes: A61F 2002/30884 : Fins or wings, e.g. longitudinal wings for preventing rotation within the bone cavity
• CPC Class Codes: A61F 2002/30889 : Arcuate pegs
• CPC Class Codes: A61F 2002/30897 : Stepped protrusions, i.e. having discrete diameter changes
• CPC Class Codes: A61F 2002/30899 : Protrusions pierced with apertures
• CPC Class Codes: A61F 2002/30971 : Laminates, i.e. layered products
• CPC Class Codes: A61F 2002/4415 : elements of the prosthesis being arranged in a chain like manner
• CPC Class Codes: A61F 2002/443 : having two transversal endplates and at least one intermediate component
• CPC Class Codes: A61F 2002/444 : for replacing the nucleus pulposus
• CPC Class Codes: A61F 2002/448 : comprising multiple adjacent spinal implants within the same intervertebral space or within the same vertebra, e.g. comprising two adjacent spinal implants
• CPC Class Codes: A61F 2002/4495 : having a fabric structure, e.g. made from wires or fibres
• CPC Class Codes: A61F 2002/4677 : using a guide wire
• CPC Class Codes: A61F 2210/0061 : swellable
• 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 2220/0075 : sutured, ligatured or stitched, retained or tied with a rope, string, thread, wire or cable
• CPC Class Codes: A61F 2220/0091 : connected by a hinged linkage mechanism, e.g. of the single-bar or multi-bar linkage type
• CPC Class Codes: A61F 2230/0015 : Kidney-shaped, e.g. bean-shaped
• CPC Class Codes: A61F 2230/0043 : L-shaped
• CPC Class Codes: A61F 2230/0058 : X-shaped
• CPC Class Codes: A61F 2230/0069 : cylindrical
• CPC Class Codes: A61F 2250/0018 : differing in elasticity, stiffness or compressibility
• CPC Class Codes: A61F 2250/0028 : differing in fibre orientations

Abstract

Prosthetic intervertebral discs, systems including such prosthetic intervertebral discs, and methods for using the same are described. The subject prosthetic discs include upper and lower endplates separated by a compressible core member. The subject prosthetic discs exhibit stiffness in the vertical direction, torsional stiffness, bending stiffness in the saggital plane, and bending stiffness in the front plane, where the degree of these features can be controlled independently by adjusting the components, construction, and other features of the discs.

Claims

1. A prosthetic intervertebral disc comprising:

a first endplate;

a second endplate attached either directly or indirectly to said first endplate in a substantially parallel relationship thereto; and

a compressible core member positioned between said first and second endplates, said compressible core having a first portion having a first stiffness and a second portion having a second stiffness, said first stiffness being greater than said second stiffness.

2. The prosthetic intervertebral disc of claim 1, wherein said first portion and said second portion of said compressible core member are formed of different materials.

3. The prosthetic intervertebral disc of claim 1, wherein said first portion of said compressible core member corresponds to a posterior aspect of the compressible core member when the disc is implanted into a patient.

4. The prosthetic intervertebral disc of claim 1, wherein said first portion of said compressible core member corresponds to an anterior aspect of the compressible core member when the disc is implanted into a patient.

5. The prosthetic intervertebral disc of claim 1, wherein said first portion of said compressible core member corresponds to a superior aspect of the compressible core member when the disc is implanted into a patient.

6. The prosthetic intervertebral disc of claim 1, wherein said first portion of said compressible core member corresponds to an inferior aspect of the compressible core member when the disc is implanted into a patient.

7. The prosthetic intervertebral disc of claim 1, wherein said second portion of said compressible core member corresponds to a middle portion of the compressible core member that is located between at least one superior portion of the core member and at least one inferior portion of the core member.

8. The prosthetic intervertebral disc of claim 7, wherein said first portion of said compressible core member corresponds to at least one of said at least one superior portion of the core member.

9. The prosthetic intervertebral disc of claim 1, wherein the stiffness of said first portion comprises between about 1000 N/mm and about 2000 N/mm, and said second stiffness comprises between about 200 N/mm and about 800 N/mm.

10. The prosthetic intervertebral disc of claim 1, wherein said first endplate and said second endplate are separated by a first distance, and wherein said prosthetic intervertebral disc is expandable between a contracted condition and an expanded condition, said first distance being greater in said expanded condition than in said contracted condition.

11. A prosthetic intervertebral disc comprising:

a first endplate;

a second endplate attached either directly or indirectly to said first endplate in a substantially parallel relationship thereto and separated by a first distance; and

a compressible core member positioned between said first and second endplates;

wherein said prosthetic intervertebral disc is expandable between a contracted condition and an expanded condition, said first distance being greater in said expanded condition than in said contracted condition.

12. The prosthetic intervertebral disc of claim 11, wherein said compressible core member comprises a hollow member adapted to be selectively inflated.

13. The prosthetic intervertebral disc of claim 12, further comprising an inflation port in fluid communication with said hollow member.

14. The prosthetic intervertebral disc of claim 12, further comprising an elongated lumen in fluid communication with said hollow member.

15. The prosthetic intervertebral disc of claim 12, wherein said hollow member comprises a plurality of chambers.

16. The prosthetic intervertebral disc of claim 15, wherein at least two of said plurality of chambers are in fluid communication with one another.

17. The prosthetic intervertebral disc of claim 11, wherein said intervertebral disc is in its contracted condition during implantation and said intervertebral disc is in its expanded condition after implantation.

18. The prosthetic intervertebral disc of claim 11, further comprising a retention mechanism configured to selectively expand said prosthetic intervertebral disc from said contracted condition to said expanded condition.

19. The prosthetic intervertebral disc of claim 18, wherein said retention mechanism comprises a shaft that extends between and selectively engages each of said first endplate and said second endplate.

20. The prosthetic intervertebral disc of claim 19, wherein said retention mechanism further comprises a locking plate associated with one of said first endplate and said second endplate.

21. The prosthetic intervertebral disc of claim 11, wherein said compressible core member has a first portion having a first stiffness and a second portion having a second stiffness, said first stiffness being greater than said second stiffness.

22. A method for surgically implanting a prosthetic intervertebral disc into a mammalian patient comprising:

providing a disc void space in the spine of the patient;

inserting a prosthetic intervertebral disc in a contracted condition into said disc void space; and

expanding said prosthetic intervertebral disc to an expanded condition in said disc void space.

23. The method of claim 22, wherein said prosthetic intervertebral disc comprises a hollow core member, and wherein expanding said prosthetic intervertebral disc comprises injecting an inflation media into said hollow member.

24. The method of claim 23, wherein said hollow core member comprises a plurality of chambers.

25. The method of claim 24, wherein at least two of said plurality of chambers are in fluid communication with one another.