Selectively expanding spine cage with enhanced bone graft infusion

• US 9,028,550 B2
• Filed: 03/13/2013
• Issued: 05/12/2015
• Est. Priority Date: 09/26/2005
• Status: Active Grant

• Current Assignee: Howmedica Osteonics Corp. (Stryker Corporation)
• Original Assignee: Coalign Innovations Inc. (Stryker Corporation)
• Inventors: Shulock, Damien J., Ashley, John E., Grotz, Thomas, Pretti, Rudy
• Primary Examiner(s): Hoffman, Mary
• Assistant Examiner(s): CARTER, TARA ROSE E
• Application Number:
  US13/799,047
• Publication Number:
  US 20130190875A1
• Time in Patent Office: 790 Days
• Field of Search: 606246-249, 606/90, 606 92- 94, 623 1711- 1716
• US Class Current: 623/17.11
• CPC Class Codes: A61F 2/30771 applied in original prostheses, e.g. holes or grooves
• CPC Class Codes: A61F 2/441 made of inflatable pockets or chambers filled with fluid, e.g. with hydrogel
• 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 2/4465 having a circular or kidney shaped cross-section substantially perpendicular to the axis of the spine
• CPC Class Codes: A61F 2/4601 for introducing bone substitute, for implanting bone graft implants or for compacting them in the bone cavity
• CPC Class Codes: A61F 2/4611 of spinal prostheses
• CPC Class Codes: A61F 2/484 Fluid means, i.e. hydraulic or pneumatic
• 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 2002/30062 (bio)absorbable, biodegradable, bioerodable, (bio)resorbable, resorptive
• 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 2002/30433 using additional screws, bolts, dowels, rivets or washers e.g. connecting screws
• CPC Class Codes: A61F 2002/30538 for adjusting angular orientation
• CPC Class Codes: A61F 2002/3055 for adjusting length
• CPC Class Codes: A61F 2002/30563 having elastic means or damping means, different from springs, e.g. including an elastomeric core or shock absorbers
• CPC Class Codes: A61F 2002/30579 with mechanically expandable devices, e.g. fixation devices
• CPC Class Codes: A61F 2002/30581 having a pocket filled with fluid, e.g. liquid
• CPC Class Codes: A61F 2002/30583 filled with hardenable fluid, e.g. curable in-situ
• CPC Class Codes: A61F 2002/30589 Sealing means
• 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 2002/30604 : modular
• CPC Class Codes: A61F 2002/30617 : Visible markings for adjusting, locating or measuring
• CPC Class Codes: A61F 2002/30622 : Implant for fusing a joint or bone material
• CPC Class Codes: A61F 2002/30772 : Apertures or holes, e.g. of circular cross section
• CPC Class Codes: A61F 2002/30777 : Oblong apertures
• CPC Class Codes: A61F 2002/4627 : with linear motion along or rotating motion about the instrument axis or the implantation direction, e.g. telescopic, along a guiding rod, screwing inside the instrument
• CPC Class Codes: A61F 2002/4629 : connected to the endoprosthesis or implant via a threaded connection
• CPC Class Codes: A61F 2002/4631 : the prosthesis being specially adapted for being cemented
• CPC Class Codes: A61F 2002/4666 : for measuring force, pressure or mechanical tension
• CPC Class Codes: A61F 2210/0085 : hardenable in situ, e.g. epoxy resins
• CPC Class Codes: A61F 2220/0041 : using additional screws, bolts, dowels or rivets, e.g. connecting screws
• CPC Class Codes: A61F 2230/0015 : Kidney-shaped, e.g. bean-shaped
• CPC Class Codes: A61F 2230/0069 : cylindrical
• CPC Class Codes: A61F 2250/0006 : for adjusting angular orientation
• CPC Class Codes: A61F 2250/0097 : Visible markings, e.g. indicia
• 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 2310/00796 : Coating or prosthesis-covering structure made of a phosphorus-containing compound, e.g. hydroxy(l)apatite

Abstract

A selectively expanding spine cage has a minimized cross section in its unexpanded state that is smaller than the diameter of the neuroforamen through which it passes in the distracted spine. The cage conformably engages between the endplates of the adjacent vertebrae to effectively distract the anterior disc space, stabilize the motion segments and eliminate pathologic spine motion. Expanding selectively (anteriorly, along the vertical axis of the spine) rather than uniformly, the cage height increases and holds the vertebrae with fixation forces greater than adjacent bone and soft tissue failure forces in natural lordosis. Stability is thus achieved immediately, enabling patient function by eliminating painful motion. The cage shape intends to rest proximate to the anterior column cortices securing the desired spread and fixation, allowing for bone graft in, around, and through the implant for arthrodesis whereas for arthroplasty it fixes to endpoints but cushions the spine naturally.

Claims

1. An apparatus for providing spinal correction, comprising:

an implant body configured and dimensioned for placement in an intervertebral space, said body defining a central cavity extending through said body configured to receive bone graft material and communicate with the intervertebral space for infusion of the graft material into the intervertebral space when placed therein, and a bone graft supply passage extending through said body and communicating with the central cavity;

a bone graft material supply port disposed on the implant body in communication with said bone graft supply passage, said port configured for attachment of a bone graft material supply line;

first and second extendable portions mounted on said body, said portions extendable from a first unexpanded height and to at least one expanded height; and

a plate with a first bone engaging surface mounted on said first and second extendable portions, said plate defining an opening aligned with the central cavity for passage there through of bone graft material from the central cavity,

wherein the implant body defines a second bone engaging surface opposite the first bone engaging surface of said plate and the central cavity is defined between said surfaces and opens through said surfaces for communication with the intervertebral space.

2. The apparatus of claim 1, wherein the bone graft supply passage has a diameter equal to approximately 60% to 75% of said unexpanded height.

3. The apparatus of claim 1, wherein said first and second extendable members comprise:

first and second cylinders defined in said implant body; and

first and second pistons received, respectively in said first and second cylinders.

4. The apparatus of claim 3, wherein said implant body defines a cylinder block containing said cylinders.

5. The apparatus of claim 4, wherein said pistons are hydraulically extendable with an incompressible fluid and said implant body further defines a hydraulic supply port and at least one hydraulic fluid passage communicating between said hydraulic supply port and said cylinders.

6. The apparatus of claim 5, wherein the hydraulic supply port and the bone graft material supply port are disposed on a proximal face of the implant body, laterally spaced apart.

7. The apparatus of claim 5, wherein the said pistons are lockable in an extended position at a desired spinal correction.

8. The apparatus of claim 7, wherein the incompressible fluid comprises a curable polymer having a fluid state for providing hydraulic force to elevate said pistons to a position that provides the desired spinal correction, and said polymer cures to a solid state to lock said pistons at said desired correction.

9. The apparatus of claim 5, wherein the implant body further defines an attachment port adjacent said bone graft material supply port.

10. The apparatus of claim 9, further comprising an insertion tool releasably engageable with said attachment port for positioning the implant.

11. The apparatus of claim 10, wherein the cylinders defined in the implant body comprise slave cylinders and said apparatus further comprises at least one remote master cylinder for providing fluid under pressure to said slave cylinders.

12. The apparatus of claim 11, wherein said insertion tool is engageable with the hydraulic supply port and includes a passage for delivering hydraulic fluid under pressure from said master cylinder.

13. The apparatus of claim 11, wherein said insertion tool is engageable with the bone graft material supply port and includes a passage for delivering bone graft material to said port from a remote supply of said material.

14. An apparatus for providing spinal correction, comprising:

an implant body configured and dimensioned for placement in an intervertebral space with a surface configured as a bone engaging surface, said body configured as a cylinder block defining first and second cylinders opening opposite said bone engaging surface and communicating with at least one hydraulic fluid passage, a central, bone graft material receiving cavity extending through said body, and a bone graft supply passage communicating with the central cavity, wherein the central cavity is configured to open to intervertebral space for infusion of the graft material into the intervertebral space when placed therein;

first and second extendable pistons sealingly received in said cylinders;

a top plate with an opposed bone engaging surface mounted on said first and second pistons, said top plate extendable with said pistons from a first unexpanded implant height and to at least one expanded implant height, said top plate defining an opening aligned with the central cavity for passage there through of bone graft material from the central cavity;

a bone graft material supply port disposed on the implant body in communication with said bone graft supply passage, said port configured for attachment of a bone graft material supply line;

a hydraulic supply port disposed on the implant body adjacent the bone graft material supply port, said hydraulic supply port communicating with said at least one hydraulic fluid passage; and

an attachment port disposed on the implant body adjacent said supply port, the attachment port being configured to receive and secure an implant insertion tool.

15. The apparatus of claim 14, wherein the cylinders defined in the implant body comprise slave cylinders and said apparatus further comprises at least one remote master cylinder for providing fluid under pressure to said slave cylinders.

16. The apparatus of claim 15, further comprising an insertion tool releasably engageable with said attachment port for positioning the implant.

17. The apparatus of claim 16, wherein:

said insertion tool is engageable with the hydraulic supply port and includes a passage for delivering hydraulic fluid under pressure from said master cylinder;

said insertion tool is engageable with the bone graft material supply port and includes a passage for delivering bone graft material to said port from a remote supply of said material.

18. The apparatus of claim 14, wherein said ports are disposed on a proximal face of the implant body, laterally spaced apart.

19. The apparatus of claim 18, wherein a distal face of the implant body comprises a narrowed leading edge to facilitate insertion and placement of the implant body in the intervertebral space.