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

• US 20080161933A1
• Filed: 10/31/2007
• Published: 07/03/2008
• Est. Priority Date: 09/26/2005
• Status: Abandoned Application

• Current Assignee: Coalign Innovations Inc. (Stryker Corporation)
• Original Assignee: Coalign Innovations Inc. (Stryker Corporation)
• Inventors: Pretti, Rudy, Grotz, R. Thomas
• Application Number:
  US11/981,452
• Publication Number:
  US 20080161933A1
• Time in Patent Office: Days
• US Class Current: 623/17.16
• 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 that the diameter of the neuroforamen through which it passes in the distracted spine. The cage conformably engages between the endplates of vertebrae to effectively distract the anterior disc space, stabilize the motion segments, eliminate pathologic spine motion, or effect vertebral body replacement. Angular deformities can be corrected, and natural curvatures restored and maintained. The cage enhances spinal arthrodesis by creating a rigid spine segment, or if filled with compressible substances, the cage can be used for motion preservation between vertebral bodies. 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 vertebral body replacement comprising:

a selectively expanding spinal implant for anterior or posterior insertion through the foraminal space between opposed superior and inferior vertebral end plates of a patient, said spinal implant comprising;

a cylinder block comprising a base resting on a first end plate and two or more slave cylinders and corresponding pistons having a corrective bone engaging surface for expanding against a second end plate.

2-34. -34. (canceled)

35. A method for providing spinal correction in three dimensions, comprising:

a. providing an interbody implant member having

i. a base including a first pressure applying, bone engaging surface;

ii. at least one extendable member cooperating with the base;

iii. a pressure applying member having a second pressure applying, bone engaging surface coupled to the extendable member;

b. removing at least part of a spinal disc between two of the patient'"'"'s vertebral bodies;

c. inserting the interbody implant member between the two vertebral bodies with the first pressure applying surface of the base engaging a surface of one of the two vertebral bodies; and

d. extending the extendable member so that the pressure applying member coupled thereto engages a surface of the other vertebral body and supports the engaged vertebral body in a desired position.

36. The method of claim 35 wherein the implant member has first and second extendable members that are extended independently to provide a desired spinal correction.

37. The method of claim 36 wherein the first and second extendable members are extended independently by hydraulic actuation to provide a desired spinal correction.

38. The method of claim 35 wherein the extendable member is extended by hydraulic actuation.

39. The method of claim 38 wherein the hydraulic actuation is by hydraulic fluid.

40. The method of claim 39 wherein the hydraulic fluid is a curable polymeric material.

41. The method of claim 40 wherein the curable polymeric material is methylmethacrylate.

42. The method of claim 39 wherein the polymeric material cures to a solid state to lock the first and second extendable member in place at a desired amount of spinal correction.

43. The method of claim 38 wherein the hydraulic fluid in a incompressible fluid.

45. The method of claim 35 wherein the base member is a cylinder block resting on a first end plate and having one or more slave cylinders and corresponding piston for expanding against a second end plate.

46. The method of claim 45 wherein 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 spinal correction.