Intervertebral disc prosthesis with contact blocks

• US 6,579,320 B1
• Filed: 07/20/2001
• Issued: 06/17/2003
• Est. Priority Date: 12/11/1998
• Status: Expired due to Fees

• Current Assignee: Stryker European Operations Holdings, LLC (Stryker Corporation)
• Original Assignee: Stryker Spine
• Inventors: Kelly, William, Saint-Martin, Pierre-Henri, Gauchet, Fabien
• Primary Examiner(s): Robert, Eduardo C.
• Application Number:
  US09/857,663
• Time in Patent Office: 697 Days
• Field of Search: 623/17.11, 623/17.13, 623/17.15, 623/17.16
• US Class Current: 623/17.15
• CPC Class Codes: A61B 17/86 Pins or screws or threaded wires; nuts therefor A61B17/72 take precedence
• 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 2/30767 Special external or bone-contacting surface, e.g. coating for improving bone ingrowth
• 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 2002/30069 elastomeric
• CPC Class Codes: A61F 2002/30112 Rounded shapes, e.g. with rounded corners
• CPC Class Codes: A61F 2002/30133 kidney-shaped or bean-shaped
• CPC Class Codes: A61F 2002/30179 X-shaped
• CPC Class Codes: A61F 2002/30225 Flat cylinders, i.e. discs
• CPC Class Codes: A61F 2002/304 with additional means for limiting said sliding
• CPC Class Codes: A61F 2002/30403 Longitudinally-oriented cooperating ribs and grooves on mating lateral surfaces of a mainly longitudinal connection
• 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 2002/30565 having spring elements
• CPC Class Codes: A61F 2002/30578 having apertures, e.g. for receiving fixation screws
• 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 2002/30599 stackable
• CPC Class Codes: A61F 2002/30975 made of two halves
• CPC Class Codes: A61F 2220/0025 Connections or couplings between prosthetic parts, e.g. between modular parts; Connecting elements
• CPC Class Codes: A61F 2230/0004 Rounded shapes, e.g. with rounded corners
• CPC Class Codes: A61F 2230/0015 Kidney-shaped, e.g. bean-shaped
• CPC Class Codes: A61F 2230/0058 : X-shaped
• CPC Class Codes: A61F 2230/0069 : cylindrical
• CPC Class Codes: A61F 2250/0063 : Nested prosthetic parts
• CPC Class Codes: A61F 2310/00023 : Titanium or titanium-based alloys, e.g. Ti-Ni alloys
• CPC Class Codes: A61F 2310/00796 : Coating or prosthesis-covering structure made of a phosphorus-containing compound, e.g. hydroxy(l)apatite

Abstract

An intervertebral disk prosthesis comprising two plates and a cushion interposed between the plates is contemplated. The cushion includes a compressible body having two ends in contact with the plates. At least one of the plates comprises at least one stud for stressing the body along a direction not parallel to a main access of the prosthesis and mobile relative to the body. Thus the prosthesis imitates and approximates the mechanical properties of a healthy natural intervertebral disk.

Claims

1. Intervertebral disc prosthesis having a main axis, comprising:

two plates, wherein at least one of the plates includes at least one contact stud; and

a deformable body interposed between the plates, wherein upon movement of the at least one of the plates having the at least one contact stud, the at least one contact stud stresses the body in a direction not parallel to the main axis of the prosthesis and the at least one contact stud is slidably movable relative to the body.

3. Prosthesis according to claim 1 or 2, wherein the at least one contact stud is located at an off-center position on the at least one plate.

4. Prosthesis according to claim 1 or 2, wherein the at least one contact stud extends from the at least one plate to a distance from the other plate when the prosthesis is not stressed.

5. Prosthesis according to claim 1 or 2, wherein the at least one contact stud has a length of between about 0.60 and about 0.90 of the distance separating the two plates when the prosthesis is not stressed.

6. Prosthesis according to claim 1 or 2, wherein the at least one contact stud immobilizes the body relative to the at least one plate so that no displacement parallel to the at least one plate occurs.

7. Prosthesis according to claim 1 or 2, wherein the at least one contact stud defines a flattened shape in a plane radial to the main axis of the prosthesis.

8. Prosthesis according to claim 1 or 2, wherein the at least one contact stud defines a flattened shape in a plane tangential to a direction circumferential to the main axis of the prosthesis.

9. Prosthesis according to claim 1 or 2, wherein a lateral face of the at least one contact stud extends continuously around an outer lateral face of the body.

10. Prosthesis according to claim 1 or 2, wherein the plate opposite the at least one plate including the at least one contact stud defines a recessed zone opposite the at least one contact stud when the prosthesis is at rest.

18. Prosthesis according to claim 1, 2 or 15, wherein each plate comprises at least two contact studs, the contact studs being arranged alternatingly around the main axis of the prosthesis.

2. Intervertebral disc prosthesis having a main axis, comprising:

two plates; and

a deformable body interposed between the plates, wherein at least one of the plates comprises at least one contact stud slidably movable in the body.

11. Intervertebral disc prosthesis having a main axis, comprising:

two plates, wherein at least one of the plates includes at least one contact stud;

a deformable body interposed between the plates, wherein upon movement of the at least one of the plates having the at least one contact stud, the at least one contact stud stresses the body in a direction not parallel to the main axis of the prosthesis and the at least one contact stud is movable relative to the body; and

wherein the body defines a recess opening into a lateral face of the body and the at least one contact stud extends in the recess opening.

12. Intervertebral disc prosthesis having a main axis, comprising:

two plates, wherein at least one of the plates includes at least one contact stud;

a deformable body interposed between the plates, wherein upon movement of the at least one of the plates having the at least one contact stud, the at least one contact stud stresses the body in a direction not parallel to the main axis of the prosthesis and the at least one contact stud is movable relative to the body; and

wherein the at least one contact stud has a cylindrical lateral face, and the body has a cylindrical face bearing on the cylindrical face of the at least one contact stud.

13. Intervertebral disc prosthesis having a main axis, comprising:

two plates, wherein at least one of the plates includes at least one contact stud;

a deformable body interposed between the plates, wherein upon movement of the at least one of the plates having the at least one contact stud, the at least one contact stud stresses the body in a direction not parallel to the main axis of the prosthesis and the at least one contact stud is movable relative to the body; and

wherein the at least one contact stud has a lateral face extending outside the body.

14. Intervertebral disc prosthesis having a main axis, comprising:

two plates, wherein at least one of the plates includes at least two contact studs arranged symmetrically about the main axis of the at least one plate; and

a deformable body interposed between the plates, wherein upon movement of the at least one of the plates having the at least two contact studs, at least one of the at least two contact studs stresses the body in a direction not parallel to the main axis of the prosthesis and the at least one contact stud is slidably movable relative to the body.

15. Intervertebral disc prosthesis having a main axis, comprising:

a first and second plate, each plate comprising at least one contact stud, the at least one contact stud of the first plate overlapping the at least one contact stud of the second plate by a length in a direction parallel to the main axis of the prosthesis when the prosthesis is not stressed.

16. Prosthesis according to claim 15, wherein the overlap length is between about 0.35 and about 0.65 of the distance separating the first and second plates when the prosthesis is not stressed.

17. Prosthesis according to claim 15 or 16, wherein the overlap length is between about 0.45 and 0.85 of the height of the contact studs parallel to the main axis of the prosthesis.

19. Intervertebral disc prosthesis comprising:

two plates;

a deformable body interposed between the plates, wherein at least one of the plates comprises at least one contact stud movable in the body; and

wherein the body defines a recess opening into a lateral face of the body and the at least one contact stud extends in the recess opening.

20. Intervertebral disc prosthesis comprising:

two plates;

a deformable body interposed between the plates, wherein at least one of the plates comprises at least one contact stud movable in the body; and

wherein the at least one contact stud has a cylindrical lateral face, and the body has a cylindrical face bearing on the cylindrical face of the at least one contact stud.

21. Intervertebral disc prosthesis comprising:

two plates;

a deformable body interposed between the plates, wherein at least one of the plates comprises at least one contact stud movable in the body; and

wherein the at least one contact stud has a lateral face extending outside the body.