Interbody spacer

• US 8,900,310 B2
• Filed: 04/05/2012
• Issued: 12/02/2014
• Est. Priority Date: 04/05/2012
• Status: Active Grant

• Current Assignee: Zimmer Biomet Spine, Inc. (Zimvie Incorporated)
• Original Assignee: Zimmer Spine, Inc. (Zimmer Biomet Holdings, Inc.)
• Inventors: Carlson, Daniel A., Hestad, Hugh D., Dant, Jack A., Davis, Reginald J.
• Primary Examiner(s): Hammond, Ellen C
• Assistant Examiner(s): JOHANAS, JACQUELINE T
• Application Number:
  US13/440,387
• Publication Number:
  US 20130268076A1
• Time in Patent Office: 971 Days
• Field of Search: 623 1711- 1716, 606/60, 606246-249
• US Class Current: 623/17.16
• 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 2/446 having a circular or elliptical cross-section substantially parallel to the axis of the spine, e.g. cylinders or frustocones
• CPC Class Codes: A61F 2/447 substantially parallelepipedal, e.g. having a rectangular or trapezoidal cross-section
• CPC Class Codes: A61F 2002/30395 with additional means for preventing or locking said rotation
• CPC Class Codes: A61F 2002/30405 made by screwing complementary threads machined on the parts themselves
• CPC Class Codes: A61F 2002/30482 using a locking cam
• CPC Class Codes: A61F 2002/30484 Mechanically expandable devices located on the first prosthetic part for locking into or onto the second prosthetic part
• CPC Class Codes: A61F 2002/305 Snap connection
• CPC Class Codes: A61F 2002/30505 spring biased
• CPC Class Codes: A61F 2002/30507 using a threaded locking member, e.g. a locking screw or a set screw
• CPC Class Codes: A61F 2002/30566 Helical springs
• 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 2002/30607 Kits of prosthetic parts to be assembled in various combinations for forming different prostheses
• CPC Class Codes: A61F 2002/30616 Sets comprising a plurality of prosthetic parts of different sizes or orientations
• CPC Class Codes: A61F 2002/30797 internally-threaded
• CPC Class Codes: A61F 2002/308 oblong
• CPC Class Codes: A61F 2002/30813 Stepped or enlarged blind bores, e.g. having discrete diameter changes
• CPC Class Codes: A61F 2002/30827 Plurality of grooves
• CPC Class Codes: A61F 2002/30841 Sharp anchoring protrusions for impaction into the bone, e.g. sharp pins, spikes
• CPC Class Codes: A61F 2002/3085 : with a threaded, e.g. self-tapping, bone-engaging surface, e.g. external surface
• CPC Class Codes: A61F 2002/30858 : Threads interrupted by grooves or sidewalls, e.g. flat sidewalls
• CPC Class Codes: A61F 2002/30878 : with non-sharp protrusions, for instance contacting the bone for anchoring, e.g. keels, pegs, pins, posts, shanks, stems, struts
• 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 or spinal implant having a spacer, a cage, and a locking mechanism, where the locking mechanism may be configured to facilitate a connection between the spacer and the cage. In some cases, the spacer may include a distal end wall, a proximal end wall, a first lateral wall, and a second lateral wall, where the locking mechanism may be situated at the proximal end wall adjacent a receiving opening in the proximal end wall. The implant may have one or more spikes extending from a top and/or a bottom of the spacer to facilitate stabilizing the implant between vertebrae after insertion of the implant in the spinal column.

Claims

1. An intervertebral implant, comprising:

a spacer having a distal end wall, a proximal end wall, a first lateral wall, and a second lateral wall, where the first lateral wall and the second lateral wall extend from the distal end wall to the proximal end wall, the spacer further having a top surface and a bottom surface opposite the top surface;

a locking mechanism situated at the proximal end wall;

a receiving opening extending into the proximal end wall;

a cage having a first portion and a second portion, where the first portion is configured to engage the receiving opening such that a distal end of the first portion is maintained proximal of the distal end wall and the second portion has discontinuous threads to engage vertebrae; and

wherein the first portion extends distal of the second portion such that the distal end of the first portion is distal of the discontinuous threads; and

wherein;

the cage has an axis of rotation;

the second portion of the cage extends a first distance in a first direction perpendicular to the axis of rotation;

the second portion of the cage extends a second distance in a second direction perpendicular to the axis of rotation and perpendicular to the first direction, where the second distance is greater than the first distance; and

when the first portion of the cage engages the receiving opening and the distal end of the first portion is maintained proximal of the distal end wall, the second portion of the cage is positionable between the first lateral wall, the second lateral wall, the top surface, and the bottom surface of the spacer.

2. The implant of claim 1, wherein:

the locking mechanism includes receiving threads; and

the first portion of the cage includes locking threads configured to engage the receiving threads.

3. The implant of claim 2, wherein the locking mechanism is configured such that rotation of the cage less than 180 degrees from an inserting position to an inserted position draws the cage against the spacer to lock the cage into the inserted position and resists further rotation of the cage in either a clockwise direction or a counter-clockwise direction.

4. The implant of claim 3, wherein the locking mechanism includes a plate insert abutting the proximal end wall and having the receiving threads for engaging the locking threads of the first portion of the cage.

5. The implant of claim 1, wherein the discontinuous threads include reverse angle threads to engage vertebrae, wherein the reverse angle threads include upper flanks and lower flanks that angle from the axis of rotation of the cage in the same direction.

6. The implant of claim 1, wherein the locking mechanism is configured such that rotation of the cage less than 180 degrees from an inserting position to an inserted position locks the cage into the inserted position and resists further rotation of the cage in either a clockwise direction or a counter clockwise direction.

7. The implant of claim 6, wherein:

the first portion of the cage includes a first deflection insert and a second deflection insert; and

the first deflection insert and the second deflection insert are configured to deflect toward one another when being received by the receiving opening.

8. The implant of claim 7, wherein the receiving opening is configured to facilitate deflecting the first deflection insert and the second deflection insert toward one another when being received by the receiving opening.

9. The implant of claim 8, wherein:

the proximal end wall has a first side and a second side and the receiving opening extends from the first side of the proximal end wall to the second side of the proximal end wall; and

when the first deflection insert and the second deflection insert are inserted through the receiving opening and engage the second side of the proximal end wall, the second portion of the cage is configured to abut the first side of the proximal end wall.

10. The implant of claim 9, wherein:

the receiving opening has an intermediate portion configured to permit movement of an inserted cage in a locking direction; and

the second side of the proximal end wall includes an indent portion extending from the second side of the proximal end wall toward the first side of the proximal end wall.

11. The implant of claim 10, wherein the indent portion has a first arcuate portion, a second arcuate portion, a first lock portion and a second lock portion.

12. The implant of claim 11, wherein the first arcuate portion is separated from the second arcuate portion by the first lock portion and the second lock portion.

13. The implant of claim 12, wherein:

the first deflection insert includes a first foot and the second deflection insert includes a second foot; and

the first lock portion receives the first foot when the cage is in an inserted position and the second lock portion receives the second foot when the cage is in the inserted position.

14. The implant of claim 1, wherein:

the cage includes an engaging member and a locking member, the locking member is configured to be inserted through the engaging member and rotatable therein;

the locking member having a locking end and a driving end;

the first portion of the cage comprises the locking end and the second portion of the cage comprises the driving end; and

the threads of the second portion of the cage include exterior threads.

15. The implant of claim 14, wherein:

the cage includes interior threads; and

the driving end includes driving threads configured to engage the interior threads.

16. The implant of claim 14, wherein:

the locking end includes a first deflection insert and a second deflection insert; and

the first deflection insert and the second deflection insert are configured to deflect toward one another when being received by the receiving opening.

17. The implant of claim 1, wherein:

the proximal end wall includes a first side and a second side;

the locking mechanism includes a post configured to extend from the first side of the proximal end wall when in a locking position.

18. The implant of claim 17, wherein:

the proximal end wall includes a locking hole extending from the first side of the proximal end wall toward the second side of the proximal end wall;

the locking hole is positioned at a lateral side of the receiving opening; and

the post is configured to translate within the locking hole.

19. The implant of claim 18, wherein:

the locking hole includes threads configured to engage threads located on the post, and

the threads on the post are configured to facilitate the translation of the locking mechanism within the locking hole.

20. The implant of claim 18, further comprising:

a spring positioned in the locking hole;

wherein the spring engages the locking mechanism and is compressed when the cage is in an inserting position;

wherein the spring is extended when the cage is in a inserted position.

21. The implant of claim 1, wherein:

when the first portion engages the receiving opening, the cage is rotatable from an inserting position and an inserted position;

when the cage is in the inserting position, the discontinuous threads of the second portion are positioned within the first lateral wall, the second lateral wall, the top surface, and the bottom surface of the spacer; and

when the cage is in the inserted position, the discontinuous threads of the second portion are positioned above the top surface and below the bottom surface of the spacer.

22. An intervertebral implant, comprising:

a spacer having a distal end wall, a proximal end wall, a first lateral wall, and a second lateral wall, where the first lateral wall and the second lateral wall extend from the distal end wall to the proximal end wall, the spacer further having a top surface and a bottom surface opposite the top surface;

a plate insert situated on a first side of the proximal end wall, the plate insert including a threaded opening;

a receiving opening extending into the proximal end wall; and

a cage having a threaded first portion and a second portion proximal of the first portion, wherein the second portion is situated on a second side of the proximal end wall opposite the first side and the threaded first portion is configured to extend through the receiving opening and threadably engage the threaded opening of the plate insert, and the second portion is configured to engage vertebrae; and

wherein the second portion of the cage is positionable between the first lateral wall, the second lateral wall, the top surface, and the bottom surface when the first portion of the cage extends through the receiving opening.

23. The intervertebral implant of claim 22, wherein rotation of the cage less than 180 degrees from an inserting position to an inserted position locks the threaded first portion of the cage with respect to the threaded opening of the plate insert.

24. The intervertebral implant of claim 23, wherein rotation of the cage to the inserted position locks the cage relative to the spacer and resists further rotation of the cage in either a clockwise direction or a counter-clockwise direction.

25. The intervertebral implant of claim 22, wherein the second portion of the cage is configured to engage vertebrae above the top surface and below the bottom surface when the first portion of the cage extends through the receiving opening.