Spine surgery method and motion preserving implant

• US 8,062,373 B2
• Filed: 06/30/2008
• Issued: 11/22/2011
• Est. Priority Date: 09/27/2005
• Status: Active Grant

• Current Assignee: Henry F. Fabian Jr
• Original Assignee: Henry F. Fabian Jr
• Inventors: Fabian, Henry F. Jr.
• Primary Examiner(s): Barrett; Thomas C.
• Assistant Examiner(s): NELSON, CHRISTINE L
• Application Number:
  US12/164,612
• Publication Number:
  US 20090048676A1
• Time in Patent Office: 1,240 Days
• Field of Search: 623/17.11, 623/13, 623/15, 623/16
• 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 2/30965 Reinforcing the prosthesis by embedding particles or fibres during moulding or dipping
• CPC Class Codes: A61F 2/441 made of inflatable pockets or chambers filled with fluid, e.g. with hydrogel
• 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 2/4455 for the fusion of spinal bodies, e.g. intervertebral fusion of adjacent spinal bodies, e.g. fusion cages intervertebral discs A61F2/442
• CPC Class Codes: A61F 2/4684 Trial or dummy prostheses
• 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 2002/30014 differing in elasticity, stiffness or compressibility
• CPC Class Codes: A61F 2002/30179 X-shaped
• 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 2002/30492 using a locking pin
• CPC Class Codes: A61F 2002/30505 spring biased
• CPC Class Codes: A61F 2002/30561 breakable or frangible
• 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 2002/30568 Multiple spring systems including two or more helical springs
• CPC Class Codes: A61F 2002/30579 with mechanically expandable devices, e.g. fixation devices
• CPC Class Codes: A61F 2002/30601 telescopic
• CPC Class Codes: A61F 2002/30616 Sets comprising a plurality of prosthetic parts of different sizes or orientations
• CPC Class Codes: A61F 2002/30836 knurled
• CPC Class Codes: A61F 2002/30841 : Sharp anchoring protrusions for impaction into the bone, e.g. sharp pins, spikes
• CPC Class Codes: A61F 2002/30904 : serrated profile, i.e. saw-toothed
• CPC Class Codes: A61F 2002/4415 : elements of the prosthesis being arranged in a chain like manner
• CPC Class Codes: A61F 2002/4619 : for extraction
• CPC Class Codes: A61F 2220/0025 : Connections or couplings between prosthetic parts, e.g. between modular parts; Connecting elements
• 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 2230/0058 : X-shaped
• CPC Class Codes: A61F 2250/0018 : differing in elasticity, stiffness or compressibility
• 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
• CPC Class Codes: A61F 2310/00029 : Cobalt-based alloys, e.g. Co-Cr alloys or Vitallium
• CPC Class Codes: A61F 2310/00179 : Ceramics or ceramic-like structures

Abstract

A spinal implant may be deployable, when positioned within a vertebral space between a pair of vertebral bodies, from a first laterally non-expanded condition to a second laterally expanded condition. The spinal implant may include top beams and bottom beams separated by at least one post that is, in one embodiment, length variable in response to a load put on the implant after deployment of the implant. In an alternate embodiment, at least one post is laterally variable in response to a load put on the implant. In another embodiment, one of the posts may be centrally located.

Claims

1. An implant comprising:

a first member comprising;

(1) a first beam having a first limb, a mid-portion, and a second limb;

(2) a second beam having a first limb, a mid-portion, and a second limb;

(3) a first post having a first end operatively connected to the first limb of the first beam and a second end operatively connected to the first limb of the second beam, the first post having a length defined as the distance between its first and second ends; and

,

(4) a second post having a first end operatively connected to the second limb of the first beam and a second end operatively connected to the second limb of the second beam, the second post having a length defined as the distance between its first and second ends;

a second member that is pivotal with respect to the first member, comprising;

(1) a first beam having a first limb, a mid-portion, and a second limb;

(2) a second beam having a first limb, a mid-portion, and a second limb;

(3) a third post having a first end operatively connected to the first limb of the first beam and a second end operatively connected to the first limb of the second beam, the third post having a length defined as the distance between its first and second ends; and

,

(4) a fourth post having a first end operatively connected to the second limb of the first beam and a second end operatively connected to the second limb of the second beam, the fourth post having a length defined as the distance between its first and second ends;

wherein the first beam of the first member and the first beam of the second member define a first contact surface that contacts the endplate of a first vertebral body;

wherein the second beam of the first member and the second beam of the second member define a second contact surface that contacts the endplate of a second vertebral body;

wherein the implant is deployable, when positioned within a vertebral space between the first and second vertebral bodies, from a first non-expanded condition where the first contact surface has a first effective footprint area A1 to a second expanded condition where the first contact surface has a second effective footprint area A2, the ratio A2/A1 is at least 1.05; and

,

wherein the first, second, third and fourth posts are length variable in response to a load put on the implant by the first and second vertebral bodies after deployment of the implant.

2. The implant of claim 1 wherein the first, second, third and fourth posts are laterally variable in response to a lateral load put on the implant by the first and second associated vertebral bodies after deployment of the implant.

3. The implant of claim 2 wherein the first, second, third and fourth posts are formed, at least partially, of a viscoelastic material that provides the length and lateral variability.

4. The implant of claim 1 wherein the first, second, third and fourth posts each comprise a spring.

5. The implant of claim 1 further wherein:

the mid-portion of the first beam of the first member and the mid-portion of the first beam of the second member are pivotally connected and define a first pivotal connection;

the mid-portion of the second beam of the first member and the mid-portion of the second beam of the second member are pivotally connected and define a second pivotal connection; and

,

the implant further comprises;

a bladder formed of a viscoelastic material that supports the first pivotal connection to the second pivotal connection.

6. The implant of claim 5 wherein the bladder is inflatable.

7. The implant of claim 1 further wherein:

the mid-portion of the first beam of the first member and the mid-portion of the first beam of the second member are pivotally connected and define a first pivotal connection;

the mid-portion of the second beam of the first member and the mid-portion of the second beam of the second member are pivotally connected and define a second pivotal connection; and

,

the implant further comprises;

a fifth post having a first end operatively connected to the first pivotal connection and a second end operatively connected to the second pivotal connection.

8. The implant of claim 7 wherein the fifth post comprises:

a first portion having a proximal end defining the first end of the fifth post and a distal end having a concave surface;

a second portion having a proximal end defining the second end of the fifth post and a distal end having a convex surface that engages the concave surface; and

,

wherein the engagement of the concave surface with the convex surface permits the first portion to pivot with respect to the second portion in response to a load put on the implant by the first and second vertebral bodies after deployment of the implant.

9. The implant of claim 7 wherein the fifth post has a longitudinal axis that is substantially collinear with the center axis of the implant.

10. The implant of claim 7 wherein the fifth post is length variable in response to a load put on the implant by the first and second vertebral bodies after deployment of the implant.

12. The implant of claim 1 wherein at least two of the first, second, third and fourth posts are length variable in response to the load put on the implant by the first and second vertebral bodies after deployment of the implant.

13. The implant of claim 12 where one of the posts that is length variable is formed of a first viscoelastic material providing a first motion characteristic and the other of the posts that is length variable is formed of a second viscoelastic material providing a second motion characteristic that is substantially different than the first motion characteristic.

11. An implant comprising:

a first member comprising;

(1) a first beam having a first limb, a mid-portion, and a second limb;

(2) a second beam having a first limb, a mid-portion, and a second limb;

(3) a first post having a first end operatively connected to the first limb of the first beam and a second end operatively connected to the first limb of the second beam, the first post having a length defined as the distance between its first and second ends; and

,

(4) a second post having a first end operatively connected to the second limb of the first beam and a second end operatively connected to the second limb of the second beam, the second post having a length defined as the distance between its first and second ends;

a second member that is pivotal with respect to the first member, comprising;

(1) a first beam having a first limb, a mid-portion, and a second limb;

(2) a second beam having a first limb, a mid-portion, and a second limb;

(3) a third post having a first end operatively connected to the first limb of the first beam and a second end operatively connected to the first limb of the second beam, the third post having a length defined as the distance between its first and second ends; and

,

(4) a fourth post having a first end operatively connected to the second limb of the first beam and a second end operatively connected to the second limb of the second beam, the fourth post having a length defined as the distance between its first and second ends;

wherein the first beam of the first member and the first beam of the second member define a first contact surface that contacts the endplate of a first associated vertebral body;

wherein the second beam of the first member and the second beam of the second member define a second contact surface that contacts the endplate of a second associated vertebral body;

wherein the implant is deployable, when positioned within a vertebral space between the first and second vertebral bodies, from a first non-expanded condition where the first contact surface has a first effective footprint area A1 to a second expanded condition where the first contact surface has a second effective footprint area A2, the ratio A2/A1 is at least 1.05; and

,

wherein at least one of the first, second, third and fourth posts is length variable in response to a load put on the implant by the first and second associated vertebral bodies after deployment of the implant.

14. The implant of claim 11 wherein the post that is length variable decreases in length in response to a compression load put on the implant by the first and second vertebral bodies after deployment of the implant.

15. The implant of claim 11 wherein the post that is length variable increases in length in response to a tensile load put on the implant by the first and second vertebral bodies after deployment of the implant.

16. The implant of claim 11 wherein the post that is length variable is formed of a viscoelastic material.

17. The implant of claim 11 wherein the post that is length variable is also laterally variable in response to a lateral load put on the implant by the first and second associated vertebral bodies after deployment of the implant.

18. The implant of claim 11 wherein the post that is length variable comprises a spring that is used to provide the length variation.

19. The implant of claim 11 wherein:

the post that is length variable comprises first and second portions separated by a space;

the first and second portions move relative to each other as the post that is length variable varies in length; and

,

at least one spring that is used to provide the length variation is positioned within the space.

20. The implant of claim 11 wherein:

the post that is length variable comprises first and second portions separated by a space;

the first and second portions move relative to each other as the post that is length variable varies in length; and

,

a viscoelastic material that is used to provide the length variation is positioned within the space.

21. The implant of claim 11 wherein:

the post that is length variable comprises first and second portions separated by a space;

the first and second portions move relative to each other as the post that is length variable varies in length; and

,

a bladder that receives a compressible fluid and that is used to provide the length variation is positioned within the space.

22. The implant of claim 11 wherein:

the post that is length variable comprises first and second portions;

the first portion comprises a cavity; and

,

at least a part of the second portions moves within the cavity as the post that is length variable varies in length.

23. The implant of claim 11 wherein:

the mid-portion of the first beam of the first member and the mid-portion of the first beam of the second member are pivotally connected and define a first pivotal connection;

the mid-portion of the second beam of the first member and the mid-portion of the second beam of the second member are pivotally connected and define a second pivotal connection; and

,

the implant further comprises;

a fifth post having a first end operatively connected to the first pivotal connection and a second end operatively connected to the second pivotal connection.

24. The implant of claim 23 wherein the fifth post comprises:

a first portion having a proximal end defining the first end of the fifth post and a distal end having a concave surface;

a second portion having a proximal end defining the second end of the fifth post and a distal end having a convex surface that engages the concave surface; and

,

wherein the engagement of the concave surface with the convex surface permits the first portion to pivot with respect to the second portion in response to a load put on the implant by the first and second vertebral bodies after deployment of the implant.

25. The implant of claim 23 wherein the fifth post has a longitudinal axis that is substantially collinear with the center axis of the implant.

26. The implant of claim 23 wherein the fifth post is length variable in response to a load put on the implant by the first and second vertebral bodies after deployment of the implant.

27. An implant comprising:

a first member comprising;

(1) a first beam having a first limb, a mid-portion, and a second limb;

(2) a second beam having a first limb, a mid-portion, and a second limb;

(3) a first post having a first end operatively connected to the first limb of the first beam and a second end operatively connected to the first limb of the second beam; and

,

(4) a second post having a first end operatively connected to the second limb of the first beam and a second end operatively connected to the second limb of the second beam;

a second member that is pivotal with respect to the first member, comprising;

(1) a first beam having a first limb, a mid-portion, and a second limb;

(2) a second beam having a first limb, a mid-portion, and a second limb;

(3) a third post having a first end operatively connected to the first limb of the first beam and a second end operatively connected to the first limb of the second beam; and

,

(4) a fourth post having a first end operatively connected to the second limb of the first beam and a second end operatively connected to the second limb of the second beam;

wherein the first beam of the first member and the first beam of the second member define a first contact surface that contacts the endplate of a first associated vertebral body;

wherein the second beam of the first member and the second beam of the second member define a second contact surface that contacts the endplate of a second associated vertebral body;

wherein the implant is deployable, when positioned within a vertebral space between the first and second vertebral bodies, from a first non-expanded condition where the first contact surface has a first effective footprint area A1 to a second expanded condition where the first contact surface has a second effective footprint area A2, the ratio A2/A1 is at least 1.05; and

,

wherein at least one of the first, second, third and fourth posts is laterally variable in response to a lateral load put on the implant by the first and second associated vertebral bodies after deployment of the implant.

28. The implant of claim 27 wherein at least two of the first, second, third and fourth posts are laterally variable in response to a lateral load put on the implant by the first and second associated vertebral bodies after deployment of the implant.

29. The implant of claim 27 wherein the post that is laterally variable is formed of a viscoelastic material.