Artificial intervertebral disc

• US 6,136,031 A
• Filed: 06/17/1998
• Issued: 10/24/2000
• Est. Priority Date: 06/17/1998
• Status: Expired due to Term

• Current Assignee: Howmedica Osteonics Corp. (Stryker Corporation)
• Original Assignee: Surgical Dynamics Incorporated (Medtronic Plc)
• Inventors: Middleton, Lance M.
• Primary Examiner(s): Smith, Jeffrey A.
• Assistant Examiner(s): Robert, Eduardo C.
• Application Number:
  US09/098,739
• Time in Patent Office: 860 Days
• Field of Search: 623/17, 623/16, 623/18
• US Class Current: 623/17.16
• CPC Class Codes: A61F 2/30744 End caps, e.g. for closing an endoprosthetic cavity
• 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 2/4465 having a circular or kidney shaped cross-section substantially perpendicular to the axis of the spine
• CPC Class Codes: A61F 2/4637 for connecting or disconnecting two parts of a prosthesis
• CPC Class Codes: A61F 2002/2835 Bone graft implants for filling a bony defect or an endoprosthesis cavity, e.g. by synthetic material or biological material
• CPC Class Codes: A61F 2002/30133 kidney-shaped or bean-shaped
• CPC Class Codes: A61F 2002/30181 Y-shaped
• CPC Class Codes: A61F 2002/30354 Cylindrically-shaped protrusion and recess, e.g. cylinder of circular basis
• CPC Class Codes: A61F 2002/30571 Leaf springs
• CPC Class Codes: A61F 2002/30593 hollow
• 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 2002/30772 Apertures or holes, e.g. of circular cross section
• CPC Class Codes: A61F 2002/30777 Oblong apertures
• CPC Class Codes: A61F 2002/30787 inclined obliquely with respect to each other
• 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 2230/0015 Kidney-shaped, e.g. bean-shaped
• CPC Class Codes: A61F 2230/006 Y-shaped
• CPC Class Codes: A61F 2310/00017 Iron- or Fe-based alloys, e.g. stainless steel
• CPC Class Codes: A61F 2310/00023 Titanium or titanium-based alloys, e.g. Ti-Ni alloys

Abstract

An intervertebral prosthesis dimensioned for insertion within an intervertebral space between adjacent vertebrae to replace at least a portion of an intervertebral disc removed therefrom, includes a disc member having sufficient rigidity to support the adjacent vertebrae in spaced relation. The disc member defines a longitudinal axis and a lateral axis transverse to the longitudinal axis. The disc member includes an exterior wall portion having a first slit with a longitudinal component of direction and a second slit with a lateral component of direction. The first and second slits are dimensioned to extend sufficiently within the exterior wall portion and are arranged relative to the longitudinal axis whereby upon insertion of the disc member within the intervertebral space forces exerted on the disc member are transferred along the exterior wall portion as facilitated by the slit arrangement. Preferably, the first slit extends in a general longitudinal direction and the second slit extends in a general lateral direction. The disc member may include an interior cavity disposed within the exterior wall portion with the first and second slits extending through the exterior wall portion in communication with the interior cavity.

Claims

1. An intervertebral prosthesis, comprising a disc member dimensioned for insertion within an intervertebral space between adjacent vertebrae to replace at least a portion of an intervertebral disc removed therefrom, the disc member defining a longitudinal axis and a lateral axis transverse to the longitudinal axis, the disc member including an exterior wall defining an interior cavity therein, the exterior wall having a first slit with a longitudinal component of direction and a plurality of second slits each with a lateral component of direction, the second slits being arranged in spaced relation along the longitudinal axis and extending to communicate with the interior cavity, the first and second slits dimensioned within the exterior wall portion and being arranged whereby upon insertion of the disc member within the intervertebral space forces exerted on the disc member are transferred along the exterior wall portion.

2. The intervertebral prosthesis according to claim 1 wherein the first slit extends in a general longitudinal direction.

3. The intervertebral prosthesis according to claim 2 wherein the second slits each extend in a general lateral direction.

4. The intervertebral prosthesis according to claim 3 wherein at least two of the second slits are disposed in at least partial overlapping relation with respect to the longitudinal axis.

5. The intervertebral prosthesis according to claim 4 wherein at least five of the second slits are disposed in at least partial overlapping relation with respect to the longitudinal axis.

6. The intervertebral prosthesis according to claim 3 wherein the first slit extends through the exterior wall and communicates with the interior cavity.

7. The intervertebral prosthesis according to claim 6 wherein the disc member includes first and second support surfaces disposed at respective longitudinal ends of the disc member and being dimensioned to supportingly engage vertebral portions of respective vertebrae.

8. The intervertebral prosthesis according to claim 7 wherein the disc member is monolithically formed having the first and second support surfaces formed therewith.

9. The intervertebral prosthesis according to claim 7 wherein at least one of the first and second support surfaces has an opening extending therethrough in communication with the interior cavity.

10. The intervertebral prosthesis according to claim 9 including an end cap mountable to the one support surface and at least partially positionable within the opening.

11. The intervertebral prosthesis according to claim 9 wherein each of the first and second support surfaces has an opening extending therethrough in communication with the interior cavity.

12. An intervertebral prosthesis, which comprises a disc member dimensioned for insertion within an intervertebral space between adjacent vertebrae to replace at least a portion of an intervertebral disc removed therefrom, the disc member defining a longitudinal axis and a lateral axis transverse to the longitudinal axis, the disc member including an exterior wall defining an interior cavity, the exterior wall having a plurality of lateral slits extending in a general lateral direction and at least one longitudinal slit extending in a general at least one of the plurality of lateral slits longitudinal direction and communicating with the interior cavity, the one longitudinal slit dimensioned to extend and interconnect two longitudinally spaced lateral slits.

13. The intervertebral prosthesis according to claim 12 including at least three lateral slits longitudinally displaced relative to the longitudinal axis and arranged to at least partially overlap to define overlapping portions.

14. The intervertebral prosthesis according to claim 12 wherein at least two of the lateral slits are longitudinally displaced relative to the longitudinal axis and disposed in at least partial overlapping relation, the one longitudinal slit extending between the at least two lateral slits.

15. The intervertebral prosthesis according to claim 14 further comprising a plurality of spaced apart longitudinal slits, each longitudinal slit interconnecting respective two longitudinally spaced lateral slits.

16. The intervertebral prosthesis according to claim 15 wherein the lateral slits each extend through the exterior wall in communication with the interior cavity.

17. An intervertebral prosthesis, comprising a body member dimensioned for insertion within an intervertebral space between adjacent vertebrae to replace at least a portion of an intervertebral disc removed therefrom, the body member having an outer wall defining an internal cavity, a longitudinal axis and a lateral axis transverse to the longitudinal axis, the outer wall having first, second and third slits defined therein, the first and second slits having a lateral component of direction and the third slit having a longitudinal component of direction and interconnecting the first and second slits, at least one of the first, second and third slits extending through the outer wall in communication with the internal cavity.

18. The intervertebral prosthesis according to claim 17, wherein the first and second slits extend in a general lateral direction.

19. The intervertebral prosthesis according to claim 17, wherein the third slit extends in a general longitudinal direction.

20. The intervertebral prosthesis according to claim 17 wherein each of the first, second and third slits extends through the outer wall in communication with the internal cavity.

21. An intervertebral prosthesis, comprising a body member dimensioned and configured to substantially conform to a general shape of the intervertebral space defined between upper and lower adjacent vertebrae to supportingly engage an adjacent vertebrae to maintain the adjacent vertebrae in spaced relation, the body member defining a longitudinal axis and a lateral axis transverse to the longitudinal axis, the body member including upper and lower support surfaces disposed at respective longitudinal ends of the body member and being dimensioned to supportingly engage respective upper and lower vertebral portions of the adjacent vertebrae, the body member having a central longitudinal opening extending through the upper and lower support surfaces, the body member having a plurality of lateral slits extending in a general lateral direction and at least one longitudinal slit extending in a general longitudinal direction, at least two of the lateral slits longitudinally and radially displaced relative to each other.

22. The intervertebral prosthesis according to claim 21 wherein the lateral slits include an upper lateral slit, an intermediate lateral slit longitudinally displaced from the upper lateral slit and a lower lateral slit longitudinally displaced from the upper and intermediate lateral slits, the intermediate slit being radially displaced relative to the upper and lower slits.

23. The intervertebral prosthesis according to claim 22 wherein the at least one longitudinal slit interconnects and communicates with the upper and lower lateral slits without communicating with the intermediate lateral slit.

24. The intervertebral prosthesis according to claim 23 wherein the body member includes an inner cavity, the lateral slits and the one longitudinal slit being dimensioned to communicate with the inner cavity.