Fusion stabilization chamber

• US 6,066,175 A
• Filed: 06/09/1998
• Issued: 05/23/2000
• Est. Priority Date: 02/16/1993
• Status: Expired due to Term

• Current Assignee: Fraser C. Henderson, John W. Newman, Rebecca Sasscer Henderson
• Original Assignee: Fraser C. Henderson, John W. Newman, Rebecca Sasscer Henderson
• Inventors: Henderson, Fraser C., Henderson, Rebecca Sasscer, Newman, John W.
• Primary Examiner(s): Willse, David H.
• Application Number:
  US09/095,418
• Time in Patent Office: 714 Days
• Field of Search: 623/17
• US Class Current: 623/17.11
• CPC Class Codes: A61B 17/7059 Cortical plates A61B17/7007, A61B17/7058 take precedence
• CPC Class Codes: A61B 17/86 Pins or screws or threaded wires; nuts therefor A61B17/72 take precedence
• CPC Class Codes: A61F 2/30744 End caps, e.g. for closing an endoprosthetic cavity
• CPC Class Codes: A61F 2/30767 Special external or bone-contacting surface, e.g. coating for improving bone ingrowth
• CPC Class Codes: A61F 2/44 for the spine, e.g. vertebrae, spinal discs
• 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 2/4455 for the fusion of spinal bodies, e.g. intervertebral fusion of adjacent spinal bodies, e.g. fusion cages intervertebral discs A61F2/442
• CPC Class Codes: A61F 2/447 substantially parallelepipedal, e.g. having a rectangular or trapezoidal cross-section
• 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 2002/30113 circular
• CPC Class Codes: A61F 2002/30153 rectangular
• CPC Class Codes: A61F 2002/30158 trapezoidal
• CPC Class Codes: A61F 2002/30261 parallelepipedal
• CPC Class Codes: A61F 2002/3028 polyhedral different from parallelepipedal and pyramidal
• CPC Class Codes: A61F 2002/30367 with additional means for preventing said rotation
• CPC Class Codes: A61F 2002/30373 with additional means for preventing said translation
• CPC Class Codes: A61F 2002/30507 using a threaded locking member, e.g. a locking screw or a set screw
• CPC Class Codes: A61F 2002/3055 for adjusting length
• CPC Class Codes: A61F 2002/30576 with extending fixation tabs
• CPC Class Codes: A61F 2002/30578 : having apertures, e.g. for receiving fixation screws
• CPC Class Codes: A61F 2002/30593 : hollow
• CPC Class Codes: A61F 2002/30601 : telescopic
• CPC Class Codes: A61F 2002/30772 : Apertures or holes, e.g. of circular cross section
• CPC Class Codes: A61F 2002/30774 : internally-threaded
• CPC Class Codes: A61F 2002/30777 : Oblong apertures
• CPC Class Codes: A61F 2002/30785 : parallel
• CPC Class Codes: A61F 2002/30787 : inclined obliquely with respect to each other
• CPC Class Codes: A61F 2002/30909 : Nets
• CPC Class Codes: A61F 2210/0004 : bioabsorbable
• CPC Class Codes: A61F 2220/0025 : Connections or couplings between prosthetic parts, e.g. between modular parts; Connecting elements
• CPC Class Codes: A61F 2220/0033 : made by longitudinally pushing a protrusion into a complementary-shaped recess, e.g. held by friction fit
• CPC Class Codes: A61F 2230/0006 : circular
• CPC Class Codes: A61F 2230/0019 : rectangular
• CPC Class Codes: A61F 2230/0026 : trapezoidal
• CPC Class Codes: A61F 2230/0063 : Three-dimensional shapes
• CPC Class Codes: A61F 2230/0082 : parallelepipedal
• CPC Class Codes: A61F 2310/00796 : Coating or prosthesis-covering structure made of a phosphorus-containing compound, e.g. hydroxy(l)apatite

Abstract

A fusion stabilization chamber stabilizes the spine following removal of one or more vertebrae, and facilitates bone growth. The chamber includes two hollow members, preferably having slightly trapezoidal cross-sections, which slide relative to each other in a telescoping manner. The hollow members preferably have walls made of a metal mesh. Barrel vaults attached to the hollow members form guides for screws which can attach the chamber to the vertebrae adjacent the corpectomy site. Because of its adjustability, the chamber can fit a wide variety of corpectomy sites. One can fill the chamber with bone material, which can eventually fuse to the adjacent bone. A pair of stabilizing plates prevents the surgeon from pushing the chamber too far towards the spinal cord. The chamber eliminates the need to maintain a large and costly inventory of screws, and neurosurgeons can learn to use it quickly and easily. In another embodiment, the device is formed in one non-telescoping piece. An end portion of the hollow member includes a curved flange which corresponds to the curvature of adjacent bone, and a notch which facilitates engagement with such bone. The device can be made in different sizes, so that it can replace relatively large vertebral bodies, as well as relatively small intervertebral discs.

Claims

1. A fusion stabilization chamber, comprising;

a) a hollow member comprising an intervertebral spacer, the hollow member having a length and a longitudinal axis,

b) the hollow member having an end portion, the end portion defining at least one hole for receiving a screw for affixing the hollow member to a surrounding bone, the end portion including at least one flange, the flange being monolithic with the hollow member, wherein the flange has a curved portion, the curved portion being shaped to correspond to a curved surface of a surrounding bone,

wherein the flange has a length which is less than the length of the hollow member,

wherein the hole is oblique relative to the longitudinal axis of the hollow member, and

wherein the hollow member has, a body portion, adjacent to said end portion, the body portion having an exterior wall which tapers down linearly, free of protrusions, from a greater width, adjacent to the end portion, to a lesser width at a position opposite to the end portion.

2. The fusion stabilization chamber of claim 1, wherein the hollow member includes at least one wall defined by a mesh, the hollow member being substantially filled with a material selected from the group consisting of bone chips, bone substitutes, and bone forming substrates having bone morphogenic proteins, and combinations of the above, and wherein the mesh defines openings sufficiently large to allow the material located within the hollow member to fuse with bone material located outside the hollow member.

3. The fusion stabilization chamber of claim 1, wherein the hollow member defines at least one notch which is shaped to engage an edge of a surrounding bone.

4. The fusion stabilization chamber of claim 1, wherein the hollow member has a trapezoidal cross-section when viewed in each of at least two mutually-orthogonal directions.

5. The fusion stabilization chamber of claim 1, wherein the end portion includes an access hole, the access hole comprising means for filling the hollow member with bone fragments.

6. The fusion stabilization chamber of claim 1, wherein the hollow member is free of any sharp protrusions.