Multi-variable-height fusion device

• US 6,706,070 B1
• Filed: 04/30/1998
• Issued: 03/16/2004
• Est. Priority Date: 05/01/1997
• Status: Expired due to Term

• Current Assignee: Zimmer Spine, Inc. (Zimmer Biomet Holdings, Inc.)
• Original Assignee: Spinal Concepts Incorporated (Zimmer Biomet Holdings, Inc.)
• Inventors: Wagner, Erik J., Dinsdale, Michael C.
• Primary Examiner(s): Snow, Bruce
• Application Number:
  US09/070,116
• Time in Patent Office: 2,147 Days
• Field of Search: 606/61, 623/17.11, 623/17.15, 623/17.16
• US Class Current: 623/17.15
• CPC Class Codes: A61B 17/8875 Screwdrivers, spanners or wrenches
• CPC Class Codes: A61F 2/30724 Spacers for centering an implant in a bone cavity, e.g. in a cement-receiving cavity
• 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 2/442 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 2/4611 of spinal 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 2002/30131 horseshoe- or crescent- or C-shaped or U-shaped
• CPC Class Codes: A61F 2002/30143 hexagonal
• CPC Class Codes: A61F 2002/30158 trapezoidal
• CPC Class Codes: A61F 2002/30166 H-shaped or I-shaped
• CPC Class Codes: A61F 2002/30224 cylindrical
• CPC Class Codes: A61F 2002/30261 parallelepipedal
• CPC Class Codes: A61F 2002/30324 differing in thickness
• CPC Class Codes: A61F 2002/30326 differing in height or in length
• CPC Class Codes: A61F 2002/30354 Cylindrically-shaped protrusion and recess, e.g. cylinder of circular basis
• CPC Class Codes: A61F 2002/3037 Translation along the common longitudinal axis, e.g. piston
• CPC Class Codes: A61F 2002/30387 Dovetail connection
• CPC Class Codes: A61F 2002/30405 made by screwing complementary threads machined on the parts themselves
• CPC Class Codes: A61F 2002/30411 : having two threaded end parts connected by a threaded central part with opposite threads at its opposite ends, i.e. for adjusting the distance between both end parts by rotating the central part
• CPC Class Codes: A61F 2002/30495 : using a locking ring
• CPC Class Codes: A61F 2002/30507 : using a threaded locking member, e.g. a locking screw or a set screw
• CPC Class Codes: A61F 2002/30515 : using a locking wedge or block
• CPC Class Codes: A61F 2002/30538 : for adjusting angular orientation
• CPC Class Codes: A61F 2002/3055 : for adjusting length
• CPC Class Codes: A61F 2002/30556 : for adjusting thickness
• CPC Class Codes: A61F 2002/30579 : with mechanically expandable devices, e.g. fixation devices
• 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 2002/30616 : Sets comprising a plurality of prosthetic parts of different sizes or orientations
• CPC Class Codes: A61F 2002/30624 : Hinged joint, e.g. with transverse axle restricting the movement
• CPC Class Codes: A61F 2002/30774 : internally-threaded
• CPC Class Codes: A61F 2002/30777 : Oblong apertures
• CPC Class Codes: A61F 2002/30785 : parallel
• CPC Class Codes: A61F 2002/30841 : Sharp anchoring protrusions for impaction into the bone, e.g. sharp pins, spikes
• CPC Class Codes: A61F 2002/448 : comprising multiple adjacent spinal implants within the same intervertebral space or within the same vertebra, e.g. comprising two adjacent spinal implants
• 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 2230/0013 : Horseshoe-shaped, e.g. crescent-shaped, C-shaped, U-shaped
• CPC Class Codes: A61F 2230/0017 : Angular shapes
• CPC Class Codes: A61F 2230/0026 : trapezoidal
• CPC Class Codes: A61F 2230/0028 : Shapes in the form of latin or greek characters
• CPC Class Codes: A61F 2230/0069 : cylindrical
• CPC Class Codes: A61F 2230/0082 : parallelepipedal
• CPC Class Codes: A61F 2250/0006 : for adjusting angular orientation
• CPC Class Codes: A61F 2250/0009 : for adjusting thickness
• CPC Class Codes: A61F 2250/0036 : differing in thickness
• CPC Class Codes: A61F 2250/0037 : differing in height or in length
• 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 2310/00179 : Ceramics or ceramic-like structures

Abstract

Alignment devices for promoting spinal fusion between neighboring vertebrae are disclosed. The alignment device may be use to alter the vertical height between the engaging plates to customize the apparatus to fit a given patient. In one embodiment, the alignment device includes two turnbuckles and two pairs of cam blocks for adjusting the height between a pair of engaging plates. The alignment device may be adapted to vary the height between the engaging plates such that the height of the apparatus proximate a first side edge is substantially different from a height of the apparatus proximate a second side edge.

Claims

1. A spinal implant for facilitating fusion between neighboring vertebrae of a spine, comprising:

a pair of engaging plates configured to fit between and engage the vertebrae to maintain a disk space between the vertebrae during use;

two cam blocks configured to be coupled to inner surfaces of the engaging plates during use;

a single substantially elongated member configured to be coupled to the two cam blocks during use, wherein the substantially elongated member is configured such that rotation of the substantially elongated member in a first angular direction moves the two cam blocks such that a height between the engaging plates is substantially increased during use, and wherein the substantially elongated member is configured such that rotation of the substantially elongated member in a second angular direction moves the two cam blocks such that the height between the engaging plates is substantially decreased during use; and

wherein the two cam blocks are configured to be positioned on the elongated member such that an anterior height and a posterior height of the engaging plates are configured to be adjusted, and wherein an anterior height of the engaging plates is different than a posterior height of the engaging plates when the engaging plates contact the vertebrae.

2. The spinal implant of claim 1 wherein the substantially elongated member comprises an exterior surface having threading disposed thereon.

3. The spinal implant of claim 1 wherein the spinal implant comprises a biocompatible material.

4. The spinal implant of claim 1, wherein the engaging plates comprise surfaces substantially planar so as to inhibit subsidence of the vertebrae during use.

5. The spinal implant of claim 1, further comprising protrusions extending from at least one of the engaging plates for enhancing an engagement between the spine and the spinal implant during use.

6. The spinal implant of claim 1, further comprising protrusions extending from at least one of the engaging plates for enhancing an engagement between the spine and the spinal implant during use, the protrusions being adapted to extend into the spine.

7. The spinal implant of claim 1 wherein at least one end of the substantially elongated member includes an indentation and wherein a tip of an adjusting tool may be inserted into the indentation such that movement of the adjusting tool causes the substantially elongated member to move.

8. The spinal implant of claim 7 wherein the adjusting tool comprises a tool selected from the group consisting of screwdrivers and allen wrenches.

9. The spinal implant of claim 1, wherein the substantially elongated member comprises a turnbuckle comprising (a) a first end having first threading in a first direction disposed thereon and (b) a second end opposite the first end, the second end having second threading in a second direction opposite the first direction disposed thereon.

10. The spinal implant of claim 9 wherein an inner surface of each of the engaging plates includes arcuate grooves configured to correspond to a shape of the turnbuckle.

11. The spinal implant of claim 9, further comprising a bracket assembly configured to separate the engaging plates during use, and wherein the bracket assembly supports the turnbuckle.

12. The spinal implant of claim 11 wherein the bracket assembly includes an arcuate opening supporting only one of the first end and the second end of the turnbuckle during use and wherein the end of the turnbuckle supported by the bracket assembly includes an indentation and wherein a tip of an adjusting tool may be inserted into the indentation such that movement of the adjusting tool causes the turnbuckle to move during use.

13. The spinal implant of claim 11 wherein the bracket assembly includes a pair of arcuate opening supporting the ends of the turnbuckle during use and wherein each of the ends of the turnbuckle includes an indentation and wherein a tip of an adjusting tool may be inserted into either of the indentations such that movement of the adjusting tool causes the turnbuckle to rotate during use.

14. The spinal implant of claim 11 wherein the bracket assembly includes a pair of arcuate openings supporting the first and second ends of the turnbuckle during use and wherein at least one of the ends of the turnbuckle includes an indentation and wherein a tip of an adjusting tool may be inserted into the indentation in at least one of the first and second ends such that movement of the adjusting tool causes the turnbuckle to rotate during use.

15. The spinal implant of claim 1 wherein an inner surface of each of the engaging plates includes sloped tracks formed therein, the sloped tracks being configured such that motion of the two cam blocks during use causes the height to vary, and wherein each of the two cam blocks comprises an upper surface and a lower surface, the upper surface and the lower surface being sloped to conform to the sloped tracks in the inner surfaces of the engaging plates.

16. The spinal implant of claim 15 wherein the surfaces of the two cam blocks and the sloped tracks in the inner surfaces of the engaging plates are configured such that movement of the two cam blocks toward the ends of the turnbuckle increases the height during use and such that movement of the two cam blocks away from the ends of the turnbuckle decreases the height during use.

17. The spinal implant of claim 15 wherein the surfaces of the two cam blocks and the sloped tracks in the inner surfaces of the engaging plates are configured such that movement of the two cam blocks toward the ends of the turnbuckle decreases the height and such that movement of the two cam blocks away from the ends of the turnbuckle increases the height during use.

18. The spinal implant of claim 1 wherein the substantially elongated member is oriented substantially parallel to and substantially adjacent an edge of the spinal implant.

20. The implant of claim 9 wherein the elongated member comprises a screw having threading disposed thereon, and wherein the cam block comprises an opening having internal threading complementary to the threading of the screw.

21. The implant of claim 14 wherein the cam block comprises sloped outer surfaces, and wherein the sloped outer surfaces are configured to engage the sloped surfaces of the tracks during use.

23. The spinal implant of claim 3 wherein the biocompatible material comprises ceramic.

24. The spinal implant of claim 3 wherein the biocompatible material comprises metal.

25. The spinal implant of claim 3 wherein the biocompatible material comprises a polymer.

26. The spinal implant of claim 3 wherein the biocompatible material comprises a composite material.

19. A spinal implant for facilitating a fusion between neighboring vertebrae of a spine, comprising:

an anterior edge located opposite a posterior edge;

a first side edge located opposite a second side edge;

a first engaging plate configured to engage a portion of a first vertebra of the neighboring vertebrae, the first engaging plate comprising a track having a first sloped surface and a second sloped surface, wherein the slope of the first sloped surface is not equal to the slope of the second sloped surface;

a second engaging plate configured to engage a portion of a second vertebra of the neighboring vertebrae, the second engaging plate comprising a track having a first sloped surface and a second sloped surface, wherein the slope of the first sloped surface is not equal to the slope of the second sloped surface; and

a single alignment device positionable between the first engaging plate and the second engaging plate and capable of maintaining a selected height between the engaging plates along a direction from a first location adjacent one of the edges to a second location adjacent the edge opposite the one of the edges during use, the alignment device comprising;

a cam block sized to fit within the tracks; and

a substantially elongated member configured to rotate during use to cause movement of the cam block within the tracks such that the selected height between the engaging plates is altered during user;

wherein the alignment device and the sloped surfaces of the tracks are configured to maintain an anterior height of the engaging plates adjacent to the anterior edge that is different from a posterior height of the engaging plates adjacent to the posterior edge to provide lordotic alignment to the vertebrae.

22. The spinal implant of claim 19, further comprising a bracket assembly configured to support the single alignment device during use.