Selectively expanding spine cage, hydraulically controllable in three dimensions for vertebral body replacement

• US 8,480,741 B2
• Filed: 12/05/2011
• Issued: 07/09/2013
• Est. Priority Date: 09/26/2005
• Status: Active Grant

• Current Assignee: Howmedica Osteonics Corp. (Stryker Corporation)
• Original Assignee: Coalign Innovations Inc. (Stryker Corporation)
• Inventors: Grotz, Thomas, Pretti, Rudy
• Primary Examiner(s): Robert, Eduardo C
• Assistant Examiner(s): CARTER, TARA ROSE E
• Application Number:
  US13/311,487
• Publication Number:
  US 20120116518A1
• Time in Patent Office: 582 Days
• Field of Search: 606246-249, 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 2/442 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 2002/30133 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 2002/30583 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 2002/30604 modular
• CPC Class Codes: A61F 2002/30617 Visible markings for adjusting, locating or measuring
• CPC Class Codes: A61F 2002/30772 Apertures or holes, e.g. of circular cross section
• CPC Class Codes: A61F 2002/4629 : connected to the endoprosthesis or implant via a threaded connection
• 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 2310/00023 : 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 diameter 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. The cage enhances spinal arthrodesis by creating a rigid spine segment. Expanding selectively, 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. Greater distraction height is achieved without an increase in implant size through the use of interfitted stages.

Claims

1. An apparatus for providing vertebral repair and replacement, comprising:

a selectively expanding spinal implant configured for insertion and rigid fixation between opposed vertebral bodies of a patient, said spinal implant comprising;

a cylinder block comprising a body configured and dimensioned for resting on a first vertebral body defining two or more slave cylinders with corresponding pistons having a corrective bone engaging surface for expanding against a second, opposed vertebral body, wherein each said piston comprises at least first and second interfitted stage.

2. The apparatus of claim 1, further comprising:

a master cylinder located away from the patient and communicating hydraulically and independently with each slave cylinder for independently operating a corresponding slave piston to impart a desired anterior/posterior spinal correction and for operating the pistons differentially for imparting desired lateral, right/left spinal correction.

3. The apparatus of claim 1, wherein said cylinder block and pistons are formed from a substantially incompressible, biocompatible material, including at least one of 6-4 titanium or polyarylethertherektone (PEEK)™

.

4. The apparatus of claim 1, wherein said interfitted piston stages are configured and dimensioned for replacement of a vertebral body between said opposed vertebral bodies.

5. The apparatus of claim 1, further comprising:

a curable polymer having a fluid state for providing hydraulic communication of mechanical force from said master cylinder to said slave cylinders to elevate said pistons to a position that provides desired spinal correction;

wherein said polymer cures to a solid state to lock said pistons at said desired correction.

6. The apparatus of claim 5, said cylinder block and pistons defining a space to confine said cured polymer, wherein said position of the expanded pistons can withstand compressive forces up to a structural failure limit of the cylinder block.

7. The apparatus of claim 6 wherein said implant can withstand compressive forces in a range from 8000-12,000 Newtons, or 3000 lbs.

8. The apparatus of claim 1, said implant having a diameter substantially in a range of 0.4-1 cm in an unexpanded state to facilitate insertion.

9. The apparatus of claim 5, said curable polymer comprising methyl methacrylate.

10. The apparatus of claim 1, said cylinder block defining a bone graft infusion aperture that is communicating with a conduit coupleable with a source of bone graft material for infusion of said bone graft material into an intervertebral space.

11. The apparatus of claim 1, said implant having a height substantially in the range of 0.1 mm in an unexpanded state to 100 mm in an expanded state.

12. A selectively expandable spinal implant for insertion between and rigid fixation of opposed vertebral bodies of a patient for reconstruction or repair of the patient'"'"'s spine, comprising:

a slave cylinder block defining at least first and second cylinders, said cylinders receiving corresponding pistons, each piston comprising at least two interfitted stages and a surface for expanding against an adjacent end plate to impart a desired spinal correction; and

a bone engaging plate moveably attached to the surface of the pistons to provide an anterior/posterior corrective angle depending on relative expansion of the pistons.

13. The spinal implant of claim 12, further comprising:

a master cylinder located away from the patient, and connected to the slave cylinders through control lines containing a hydraulic fluid said matter cylinder providing independent, selective hydraulic actuation of the slave pistons;

wherein independent operation of the slave pistons imparts a desired anterior/posterior spinal correction and wherein differential operation of the pistons with respect to one another imparts a desired lateral spinal correction.

14. The spinal implant of claim 13, said hydraulic fluid comprising a polymer that cures to a solid state to lock the slave pistons immovably in place at a desired amount of spinal correction.

15. The spinal implant of claim 14, said hydraulic fluid comprising methylmethacrylate.

16. The spinal implant of claim 14, said slave cylinder block and pistons further comprising a biocompatible, substantially incompressible material for confining the curable polymer, wherein a desired amount of spinal correction imparted by the expanded pistons is capable of withstanding compressive forces up to a structural failure limit of the cylinder block.

17. The spinal implant of claim 16, wherein the slave cylinder block and pistons comprise titanium or an alloy thereof.

18. The spinal implant of claim 16, wherein the slave cylinder block and pistons comprise stainless steel.

19. The spinal implant of claim 16, wherein the slave cylinder block and pistons comprise any of biodegradable and biologically active materials and polyarylethertherektone (PEEK)™

.