Height adjustable spinal prostheses

• US 20080243254A1
• Filed: 03/29/2008
• Published: 10/02/2008
• Est. Priority Date: 03/29/2007
• Status: Active Grant

• Current Assignee: Life Spine, Inc.
• Original Assignee: Life Spine, Inc.
• Inventors: Butler, Michael S.
• Granted Patent: US 9,237,954 B2
• Time in Patent Office: Days
• 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 2/44 for the spine, e.g. vertebrae, spinal discs
• CPC Class Codes: A61F 2002/30133 kidney-shaped or bean-shaped
• CPC Class Codes: A61F 2002/30235 tubular, e.g. sleeves
• CPC Class Codes: A61F 2002/30492 using a locking pin
• CPC Class Codes: A61F 2002/30507 using a threaded locking member, e.g. a locking screw or a set screw
• CPC Class Codes: A61F 2002/30525 Worm gears
• CPC Class Codes: A61F 2002/3055 for adjusting length
• CPC Class Codes: A61F 2002/30593 hollow
• 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 2002/30777 Oblong apertures
• CPC Class Codes: A61F 2002/30841 Sharp anchoring protrusions for impaction into the bone, e.g. sharp pins, spikes
• CPC Class Codes: A61F 2220/0025 Connections or couplings between prosthetic parts, e.g. between modular parts; Connecting elements
• CPC Class Codes: A61F 2230/0015 Kidney-shaped, e.g. bean-shaped
• CPC Class Codes: A61F 2230/0069 cylindrical
• 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

Dimensionally adjustable spinal prostheses are adjustable in an axial or superior to inferior dimension such that spinal prostheses may assume variations in height. The height adjustable spinal prostheses are characterized by first and second portions that are configured for adjustable coupling with one another. Spatial adjustment between the first and second portions is provided by an adjustment assembly. The adjustment mechanism preferably, but not necessarily, provides infinite adjustment over a minimum prosthesis height to a maximum prosthesis height. In one form, first and second ends of the height adjustable spinal prostheses are configured to receive an endplate. The endplates aid in attachment and/or anchoring of the spinal prosthesis within the spine. The endplates may be fashioned in various configurations such as circular or anatomical. In one form, the adjustment assembly utilizes rotational motion for varying the axial position of one prosthetic portion relative to the other prosthetic portion. Rotational movement of an adjustment mechanism of the adjustment assembly is translated into axial movement of one prosthetic portion relative to the other prosthetic portion. In another form, the adjustment mechanism is a screw and gearing assembly. In yet another form, the adjustment mechanism is a rack and pinion assembly.

Claims

1. A spinal prosthesis comprising:

a first prosthetic portion;

a second prosthetic portion coupled for axial displacement of the second prosthetic portion relative to the first prosthetic portion; and

an adjustment mechanism coupled to the first and second prosthetic portions and operable to effect axial displacement of the second prosthetic portion relative to the first prosthetic portion.

2. The spinal prosthesis of claim 1, wherein the adjustment mechanism is operable to effect variable axial displacement of the second prosthetic portion relative to the first prosthetic portion.

3. The spinal prosthesis of claim 1, wherein the adjustment mechanism utilizes rotational motion for effecting axial displacement of the second prosthetic portion relative to the first prosthetic portion.

4. The spinal prosthesis of claim 3, wherein the adjustment mechanism comprises an axial screw gear and a transverse gear in meshing relationship with the axial screw gear for the rotational motion.

5. The spinal prosthesis of claim 3, wherein the adjustment mechanism comprises a rack and pinion assembly for the rotational motion.

6. The spinal prosthesis of claim 3, wherein the adjustment mechanism comprises a first rack and pinion assembly and a second rack and pinion assembly for the rotational motion.

7. The spinal prosthesis of claim 6, wherein:

the first rack and pinion assembly comprises a first rack associated with the first prosthetic portion and a first pinion associated with the second prosthetic portion; and

the second rack and pinion assembly comprises a second rack associated with the first prosthetic portion and a second pinion associated with the second prosthetic portion.

8. The spinal prosthesis of claim 7, wherein:

the first and second racks are disposed internal to the first prosthetic portion; and

the first and second pinions are disposed internal to the second prosthetic portion.

9. The spinal prosthesis of claim 6, wherein:

the first rack and pinion assembly comprises a first rack associated with the second prosthetic portion and a first pinion associated with the first prosthetic portion; and

the second rack and pinion assembly comprises a second rack associated with the second prosthetic portion and a second pinion associated with the second prosthetic portion.

10. The spinal prosthesis of claim 9, wherein:

the first and second racks are disposed internal to the second prosthetic portion; and

the first and second pinions are disposed internal to the first prosthetic portion and extend into the second prosthetic portion.

11. The spinal prosthesis of claim 1, wherein the adjustment mechanism comprises a radially adjustable collar situated about the first portion.

12. The spinal prosthesis of claim 1, wherein:

the first portion includes a first end configured to receive a first end plate for contact with a first vertebral surface; and

the second portion includes a second end configured to receive a second end plate for contact with a second vertebral surface that is adjacent the first vertebral surface.

13. A spinal prosthesis comprising:

a first prosthetic portion having an interior chamber;

a second prosthetic portion configured for and received in the interior chamber of the first prosthetic portion, the second prosthetic axially displaceable relative to the first prosthetic portion; and

an adjustment mechanism coupled to the first and second prosthetic portions and operable to effect axial displacement of the second prosthetic portion relative to the first prosthetic portion.

14. The spinal prosthetic of claim 13, wherein the adjustment mechanism is operable to effect variable axial displacement of the second prosthetic portion relative to the first prosthetic portion.

15. The spinal prosthesis of claim 13, wherein the adjustment mechanism utilizes rotational motion for effecting axial displacement of the second prosthetic portion relative to the first prosthetic portion.

16. The spinal prosthesis of claim 15, wherein the adjustment mechanism comprises an axial screw gear disposed in the interior chamber and connected to the second prosthetic portion, and a transverse gear disposed in the interior chamber and in meshing relationship with the axial screw gear for the rotational motion.

17. The spinal prosthesis of claim 15, wherein the adjustment mechanism comprises a rack and pinion assembly for the rotational motion.

18. The spinal prosthesis of claim 15, wherein the adjustment mechanism comprises a first rack and pinion assembly and a second rack and pinion assembly for the rotational motion.

19. The spinal prosthesis of claim 18, wherein:

the first rack and pinion assembly comprises a first rack associated with the first prosthetic portion and a first pinion associated with the second prosthetic portion; and

the second rack and pinion assembly comprises a second rack associated with the first prosthetic portion and a second pinion associated with the second prosthetic portion.

20. The spinal prosthesis of claim 19, wherein:

the first and second racks are disposed internal to the first prosthetic portion; and

the first and second pinions are disposed internal to the second prosthetic portion.

21. The spinal prosthesis of claim 18, wherein:

the first rack and pinion assembly comprises a first rack associated with the second prosthetic portion and a first pinion associated with the first prosthetic portion; and

the second rack and pinion assembly comprises a second rack associated with the second prosthetic portion and a second pinion associated with the second prosthetic portion.

22. The spinal prosthesis of claim 21, wherein:

the first and second racks are disposed internal to the second prosthetic portion; and

the first and second pinions are disposed internal to the first prosthetic portion and extend into the second prosthetic portion.

23. The spinal prosthesis of claim 13, wherein the adjustment mechanism comprises a radially adjustable collar situated about the first portion.

24. The spinal prosthesis of claim 13, wherein:

the first portion includes a first end configured to receive a first end plate for contact with a first vertebral surface; and

the second portion includes a second end configured to receive a second end plate for contact with a second vertebral surface that is adjacent the first vertebral surface.

25. A spinal prosthesis comprising:

a lower prosthetic portion having an interior chamber;

an upper prosthetic portion coupled for axial displacement within the interior chamber of the lower prosthetic portion relative to the lower prosthetic portion whereby height of the spinal prosthesis is varied; and

an adjustment mechanism coupled to the upper and lower prosthetic portions and operable to effect axial displacement of the upper prosthetic portion relative to the lower prosthetic portion.