INTERBODY SPACER

• US 20130268076A1
• Filed: 04/05/2012
• Published: 10/10/2013
• 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.
• Granted Patent: US 8,900,310 B2
• Time in Patent Office: Days
• 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;

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 and the second portion is threaded to engage vertebrae.

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 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 cage includes reverse angle threads to engage vertebrae, wherein the reverse angle threads include upper flanks and lower flanks that angle from a rotational axis 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 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. A spinal 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 and each wall has a top and a bottom;

a spike extending from the top and the bottom of the spacer;

a receiving opening situated at the proximal end wall; and

a cage configured to engage the receiving opening and rotatable relative to the spacer.

22. The implant of claim 21, wherein the spike is axially compressible from a first length to a second length.

23. The implant of claim 22, wherein the spike includes slots configured to facilitate axial compression of the spike.

24. A method of assembling an intervertebral implant, where the implant includes a spacer having a distal end wall, a proximal end wall, a first lateral wall, and a second end wall, and a cage configured to engage the spacer at a receiving opening in the proximal end wall, the method comprising:

inserting the spacer and cage into a disc space between adjacent vertebrae with the cage in an inserting position;

rotating the cage less than 180 degrees from the inserting position to an inserted position in which threads of the cage engage the adjacent vertebrae;

wherein rotating the cage less than 180 degrees from the inserting position to the inserted position locks the cage in place with respect to the spacer such that the cage resists further rotation in either direction.

25. The method of claim 24, wherein:

the cage includes locking threads and the receiving opening includes receiving threads; and

the rotating step includes engaging the locking threads with the receiving threads.

26. The method of claim 24, wherein the rotating the cage step includes rotating feet of the cage to the inserted position.

27. The method of claim 24, further comprising:

releasing a post after rotating the cage; and

wherein the released post is configured to abut the cage to facilitate locking the cage in place.

28. The method of claim 24, wherein the spacer includes a cam extending from a first side of the proximal end wall;

and

wherein the rotating the cage step includes rotating the cage over an end of the cam to lock the cage in place with respect to the spacer.