Bone reinforcers

• US 6,494,883 B1
• Filed: 05/26/2000
• Issued: 12/17/2002
• Est. Priority Date: 05/26/2000
• Status: Expired due to Fees

• Current Assignee: Anova Corp.
• Original Assignee: Bret A. Ferree
• Inventors: Ferree, Bret A.
• Primary Examiner(s): Reip, David O.
• Assistant Examiner(s): DAVIS, DANIEL J
• Application Number:
  US09/580,231
• Time in Patent Office: 935 Days
• Field of Search: 623/16.11, 623/17.11, 623/17.16, 623/23.47, 623/23.51, 623/23.53, 606/61
• US Class Current: 606/247
• CPC Class Codes: A61F 2/28 Bones joints A61F2/30
• 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 2/4465 having a circular or kidney shaped cross-section substantially perpendicular to the axis of the spine
• 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 2002/2839 Bone plugs or bone graft dowels
• CPC Class Codes: A61F 2002/30014 differing in elasticity, stiffness or compressibility
• CPC Class Codes: A61F 2002/30062 (bio)absorbable, biodegradable, bioerodable, (bio)resorbable, resorptive
• CPC Class Codes: A61F 2002/30224 cylindrical
• CPC Class Codes: A61F 2002/30329 Connections or couplings between prosthetic parts, e.g. between modular parts; Connecting elements
• CPC Class Codes: A61F 2002/30357 Stepped cylinders, i.e. having discrete diameter changes
• CPC Class Codes: A61F 2002/30405 made by screwing complementary threads machined on the parts themselves
• CPC Class Codes: A61F 2002/30507 using a threaded locking member, e.g. a locking screw or a set screw
• CPC Class Codes: A61F 2002/30546 for adjusting elasticity, flexibility, spring rate or mechanical tension
• CPC Class Codes: A61F 2002/30593 hollow
• CPC Class Codes: A61F 2002/30622 Implant for fusing a joint or bone material
• 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 2002/30841 : 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 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 2230/0069 : cylindrical
• CPC Class Codes: A61F 2250/0012 : for adjusting elasticity, flexibility, spring rate or mechanical tension
• CPC Class Codes: A61F 2250/0018 : differing in elasticity, stiffness or compressibility
• CPC Class Codes: A61F 2310/00011 : Metals or alloys

Abstract

Existing bone dowels are improved through the use of rigid, preferably metallic end plates. The plates are positioned relative to the anterior and posterior end surfaces of the bone dowel, which may be an existing, modified, or a specially fabricated bone section. The completed structure may be inserted, removed, and positioned into the vertebrae in the same manner as existing devices, that is, by way of a threaded or frictional fit, just as the dowel being fortified. However, the use of the rigid endplates facilitates load sharing which helps to prevent graft fracture. In the preferred embodiment, the end plates are positioned against the end surfaces of the bone section through the use of a link member, which passes through the interior of the bone section and connects the end plates. One of the end plates may include a threaded bore, and one end of the link member may be threaded to receive the threaded bore of that end plate to hold it in place. The use of a link member allows a plurality of bone sections to be journaled onto the link member, with a disk of rigid, preferably metallic material to be interposed between each bone section. Alternatively, the end surfaces of the bone section may each include an aperture having an inside diameter, with each end plate having an outside diameter corresponding to the inside diameter of the apertures, enabling the end plates to be positioned against the end surfaces of the bone section through a frictional fit.

Claims

1. A reinforced bone plug, comprising:

a mid section formed from a piece of natural or synthetic bone having opposing ends; and

a pair of rigid, non-bone end plates, each positioned against a respective end of the mid section.

2. The reinforced bone plug of claim 1, wherein the end plates are at least partially metallic.

3. The reinforced bone plug of claim 1, including at least one link member that passes through the mid section so as to interconnect the opposing ends.

4. The reinforced bone plug of claim 3, wherein:

one of the end plates includes a threaded bore; and

one end of the link member is threaded to receive the threaded bore of that end plate.

5. The reinforced bone plug of claim 1, further including:

a plurality of mid sections; and

a disk of rigid material disposed between each mid section.

6. The reinforced bone plug of claim 1, wherein the mid section includes cancellous bone.

7. The reinforced bone plug of claim 1, wherein the mid section includes cortical bone.

8. The reinforced bone plug of claim 1, wherein:

each end of the mid section includes an aperture having an inside diameter;

each end plate includes a feature having an outside diameter corresponding to the inside diameter of the apertures; and

wherein the end plates are positioned against the end surfaces of the bone mid section through a frictional fit between the inside and outside diameters.

9. The reinforced bone plug of claim 1, wherein the ends of the bone mid section are threaded to receive the end plates.

10. The reinforced bone plug of claim 1, wherein the mid section in combination with the end plates assumes a generally cylindrical, threaded configuration permitting a screw-in installation.

11. The reinforced bone plug of claim 1, wherein the mid section in combination with the end plates assumes a configuration suitable to an impacted installation.

12. The reinforced bone plug claim 1, wherein at least the mid section includes serrading or protrusions to hold the plug in position once installed.