DISTRACTABLE SPINAL IMPLANT ASSEMBLY

• US 20090204218A1
• Filed: 02/13/2008
• Published: 08/13/2009
• Est. Priority Date: 02/13/2008
• Status: Active Grant

• Current Assignee: Intelligent Implant Systems, LLC
• Original Assignee: Intelligent Implant Systems, LLC
• Inventors: Richelsoph, Marc
• Granted Patent: US 8,216,314 B2
• Time in Patent Office: Days
• US Class Current: 623/17.160
• CPC Class Codes: A61F 2/4425 made of articulated components
• CPC Class Codes: A61F 2/4637 for connecting or disconnecting two parts of a prosthesis
• 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 2002/30369 Limited lateral translation of the protrusion within a larger recess
• CPC Class Codes: A61F 2002/30476 locked by an additional locking mechanism
• CPC Class Codes: A61F 2002/30556 for adjusting thickness
• CPC Class Codes: A61F 2002/30649 Ball-and-socket joints
• 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 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 2230/0069 cylindrical
• CPC Class Codes: A61F 2250/0009 for adjusting thickness
• 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
• CPC Class Codes: A61F 2310/0058 Coating made of diamond or of diamond-like carbon DLC
• CPC Class Codes: A61F 2310/0088 : Coating made of titanium nitride

Abstract

A spinal implant assembly includes a housing for containing a bearing member therein and seating within an intervertebral space and a bearing member disposed within the housing for enabling disc-like movement between vertebrae defining the intervertebral space. The combination of the housing and bearing member provide a distracting mechanism disposed within the housing halves 12, 14 for distracting the housing halves 12, 14 from a first condition in which the housing halves 12, 14 are floatable into the intervertebral space to a second condition in which the housing halves 12, 14 are distracted to fixedly engage the opposing vertebral services defining the intervertebral space. A method of inserting the spinal implant assembly into the intervertebral space includes the steps of inserting the spinal implant assembly into the intervertebral space and then distracting the spinal implant assembly from a first condition in which the spinal implant assembly is floatable into the intervertebral space to a second condition in which the assembly is distracted to fixedly engage opposing vertebral services defining the intervertebral space,

Claims

1. A spinal implant assembly comprising

housing means for containing a bearing member therein and seating within an intervertebral space;

bearing means disposed within said housing for enabling disc like movement between vertebrae defining the intervertebral space; and

distracting means disposed within said housing for distracting said housing means from a first condition in which said housing means is floatable into the intervertebral space to a second condition in which said housing means is distracted to fixedly engage the opposing vertebral surfaces defining the intervertebral space.

2. The spinal implant assembly as set forth in claim 1, wherein said housing means includes at least a first and second housing member for containing said bearing means therein and therebetween, at least one of said housing means including a ramping surface over which said bearing means seats and travels whereby translating of said bearing means from a first position on said ramping surface to a second position on said ramping surface distracts said housing means from said first condition to said second condition.

3. The spinal implant assembly as set forth in claim 2, wherein each of said housing members includes a recessed opening therein juxtaposed to each other defining an internal housing cavity, and seating said bearing means therein, at least one of said recessed openings including said ramping surface.

4. The spinal implant assembly as set forth in claim 3, wherein said ramping surface includes a bearing seating cavity recessed relative to a high point of said ramping surface, said high point producing maximal distraction of said housing when said bearing means is seated thereon, said bearing means being restricted from further translation on said ramping surface when said bearing means is seated in said bearing seating cavity.

5. The spinal implant assembly as set forth in claim 4, wherein said bearing seating cavity seats said bearing means at a desired center of rotation.

6. The spinal implant assembly as set forth in claim 5, including center of motion adjustment means for adjusting the position of said bearing means relative to said housing while said bearing means is seated in said bearing seating cavity and after said assembly is distracted within a vertebral space.

7. The spinal implant assembly as set forth in claim 6, wherein said center of motion adjustment means includes a base member seated within said internal housing cavity for translation over said ramping surface, said bearing means being seated therein, said assembly including ratcheting engagement means for defining engagement sites between said base member and said ramping surface and locking said base member in any of several positions relative to said internal housing cavity, thereby allowing the center of rotation of said assembly to be adjusted.

8. The spinal implant assembly as set forth in claim 7, wherein one of said base member and ramping surface include projections and the other includes recesses for engaging each other and defining said engagement means.

9. The spinal implant assembly as set forth in claim 8, wherein said bearing means includes a cylindrical portion seated within said bearing seating cavity and against said ramping surface and a hemispherical portion integrally connected thereto providing a bearing surface against a bearing surface of said internal housing cavity, opposite said ramping surface.

10. The spinal implant assembly as set forth in claim 9, wherein said hemispherical portion includes a highly polished hemispherical surface.

11. The spinal implant assembly as set forth in claim 10, wherein said hemispherical surface includes a treatment selected from the group including diamond-like coatings and titanium nitrate.

12. The spinal implant assembly as set forth in claim 11, wherein said bearing means includes anti-rotation means for preventing rotation of said bearing means relative to said internal housing cavity.

13. The spinal implant assembly as set forth in claim 12, wherein said bearing means includes an oblong portion defining said anti-rotation means seated against said ramping surface and a hemispherical portion integrally connected thereto providing a bearing surface against a bearing surface of said internal housing cavity opposite said ramping surface.

14. The spinal implant assembly as set forth in claim 13, wherein said hemispherical portion includes a highly polished hemispherical surface.

15. The spinal implant assembly as set forth in claim 14, wherein said hemispherical surface includes a treatment selected from the group including diamond-like coatings and titanium nitrate.

16. The spinal implant assembly as set forth in claim 9, wherein said internal housing cavity is larger than a largest cross-sectional dimension of said cylindrical portion providing clearance therebetween and allowing said bearing means to free float along a length of said internal housing cavity thereby allowing adjustments of a center of rotation between more than one of said assemblies.

17. The spinal implant assembly as set forth in claim 3, including a base member disposed within said internal housing cavity for containing said bearing means therein and biasing means disposed between said base member and said ramping surface provided cushioned movement of said base member towards and away from said ramping surface thereby allowing lateral bending of vertebrae about said spinal implant assembly.

18. The spinal implant assembly as set forth in claim 17, wherein said biasing means is a Bellville washer.

19. The spinal implant assembly as set forth in claim 18, wherein said washer is made from a material from a group including titanium, cobalt, chrome and stainless steel and polymers.

20. The spinal implant assembly as set forth in claim 18, wherein said polymer is selected from the group including silicone, hydrogels, and polyurethanes.

21. The spinal implant assembly as set forth in claim 1, wherein said bearing means includes a bearing head including a bearing surface thereon and a bottom portion seated against a ramping surface within an internal housing cavity,

22. The spinal implant assembly as set forth in claim 21, wherein said bearing head and said bottom portion are an integral unit.

23. The spinal implant assembly as set forth in claim 21, wherein said bearing head includes connecting means for connecting said bearing head to said bottom portion.

24. The spinal implant assembly as set forth in claim 23, including biasing means interconnecting said bearing head and said bottom portion allowing relative controlled motion therebetween.

25. The spinal implant assembly as set forth in claim 24, wherein said bearing head includes an internal pocket having an annular recess therein and said bottom portion including an annular recess therein and said biasing means including an annular spring member fixedly seated in and sandwiched between said recesses.

26. A spinal implant assembly comprising

housing means;

bearing means disposed within said housing means for enabling disc-like movement between vertebrae defining an intervertebral space; and

adjustment means for adjusting a center of rotation of said assembly relative to the intervertebral space after said assembly has been inserted into the intervertebral space.

27. A spinal implant assembly comprising

stabilizing means for stabilizing an intervertebral space;

and

motion restoring means for restoring anatomical motion to vertebrae defining the intervertebral space.

28. A method of inserting a spinal implant assembly into an intervertebral space, said method including the steps of:

inserting the spinal implant assembly into an intervertebral space and then distracting the spinal implant assembly from a first condition in which the spinal implant assembly is floatable into the intervertebral space to a second condition in which the assembly is distracted to fixedly engage opposing vertebral surfaces defining the intervertebral space.

29. The method as set forth in claim 28, further including the steps of retracting the spinal implant assembly after implantation into the intervertebral space and removing the implant therefrom.

30. The method as set forth in claim 28, wherein said distracting step is further defined as distracting the spinal implant assembly into the second condition while expanding the intervertebral space.

32. The method as set forth in claim 30, wherein said adjusting step is further defined as inter-operatively altering the center of rotation after the spinal implant assembly is inserted into the intervertebral space while not disturbing interfaces between the adjacent vertebrae and the spinal implant assembly.

31. A method of inserting a spinal implant assembly into an intervertebral space, said method including the step of:

adjusting the center of rotation of the spinal implant assembly after the assembly has been inserted into the intervertebral space.

33. A method of inserting a spinal implant assembly into an intervertebral space, said method including the steps of:

inserting the spinal implant assembly into the intervertebral space;

stabilizing the intervertebral space; and

restoring anatomical motion to the vertebrae defining the intervertebral space.

34. A method of inserting a spinal implant assembly into an intervertebral space by posteriorly inserting two spinal implant assemblies into the intervertebral space, and adjusting the center of rotation of each of the implants in situ.

35. An insert member for a spinal implant assembly comprising:

a cylindrical portion including a first end having a substantially fiat surface and

a bearing portion operatively connected to second end of said cylindrical portion.

36. The insert member as set forth in claim 35, wherein said bearing portion is substantially hemispherical.