Intervertebral spacer having a flexible wire mesh vertebral body contact element

• US 20030014116A1
• Filed: 04/23/2002
• Published: 01/16/2003
• Est. Priority Date: 07/16/2001
• Status: Active Grant

• Current Assignee: Howmedica Osteonics Corp. (Stryker Corporation)
• Original Assignee: Spinecore, Inc. (Stryker Corporation)
• Inventors: Ralph, James D., Tatar, Stephen, Errico, Thomas J.
• Granted Patent: US 6,863,689 B2
• Time in Patent Office: Days
• US Class Current: 623/17.16
• CPC Class Codes: A61B 17/025 Joint distractors
• CPC Class Codes: A61B 2017/0256 for the spine
• CPC Class Codes: A61F 2/30742 Bellows or hose-like seals; Sealing membranes A61B17/8808 takes precedence; sealing membranes for retaining bone substitute A61F2/2846
• CPC Class Codes: A61F 2/30767 Special external or bone-contacting surface, e.g. coating for improving bone ingrowth
• 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 2/4425 made of articulated components
• 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 2/4611 of spinal prostheses
• CPC Class Codes: A61F 2/4684 Trial or dummy prostheses
• CPC Class Codes: A61F 2002/30171 rosette- or star-shaped
• CPC Class Codes: A61F 2002/302 toroidal, e.g. rings
• CPC Class Codes: A61F 2002/30433 using additional screws, bolts, dowels, rivets or washers e.g. connecting screws
• CPC Class Codes: A61F 2002/30451 soldered or brazed or welded
• CPC Class Codes: A61F 2002/30492 using a locking pin
• CPC Class Codes: A61F 2002/305 Snap connection
• CPC Class Codes: A61F 2002/30518 with possibility of relative movement between the prosthetic parts
• CPC Class Codes: A61F 2002/30565 having spring elements
• CPC Class Codes: A61F 2002/30571 Leaf springs
• 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 2002/30649 : Ball-and-socket joints
• CPC Class Codes: A61F 2002/30769 : madreporic
• CPC Class Codes: A61F 2002/30774 : internally-threaded
• CPC Class Codes: A61F 2002/30909 : Nets
• CPC Class Codes: A61F 2002/3092 : having an open-celled or open-pored structure
• CPC Class Codes: A61F 2002/30975 : made of two halves
• CPC Class Codes: A61F 2002/443 : having two transversal endplates and at least one intermediate component
• 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 2002/4628 : with linear motion along or rotating motion about an axis transverse to the instrument axis or to the implantation direction, e.g. clamping
• CPC Class Codes: A61F 2220/0025 : Connections or couplings between prosthetic parts, e.g. between modular parts; Connecting elements
• CPC Class Codes: A61F 2220/0041 : using additional screws, bolts, dowels or rivets, e.g. connecting screws
• CPC Class Codes: A61F 2220/0058 : soldered or brazed or welded
• CPC Class Codes: A61F 2230/005 : Rosette-shaped, e.g. star-shaped
• CPC Class Codes: A61F 2230/0065 : toroidal, e.g. ring-shaped, doughnut-shaped
• 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 2310/00365 : Proteins; Polypeptides; Degradation products thereof

Abstract

A porous intervertebral spacer having a flexible wire mesh as a vertebral body contact surface, the flexible wire mesh preferably being a convex titanium mesh laser-welded at its perimeter to the spacer. The mesh is domed in its initial undeflected conformation, but deflects as necessary during insertion of the spacer between vertebral bodies, and, once the spacer is seated between the vertebral bodies, deforms as necessary under anatomical loads to reshape itself to the concave surface of the vertebral endplate, providing gripping and holding strength upon initial implantation, and an osteoinductive surface through which the bone may ultimately grow, making the fixation of the spacer between the vertebral bodies secure.

Claims

1. An intervertebral spacer having an osteoinductive securing surface element, the intervertebral spacer comprising:

a spacer body, said spacer body comprising at least one vertebral body contact element for securably mating with a concave surface of an adjacent vertebral body endplate;

said vertebral body contact element comprising a flexible wire mesh;

said flexible wire mesh being deformably reshapable under anatomical loads such that said flexible wire mesh conformably deflects within said concave surface to securably engage said vertebral body endplate.

2. The intervertebral spacer of claim 1, wherein the wire mesh has a resting shape in the shape of a dome convexly extending from the spacer body.

3. The intervertebral spacer of claim 1, wherein the wire mesh is laser-welded to the spacer body.

4. The intervertebral spacer of claim 1, wherein the wire mesh comprises titanium.

5. The intervertebral spacer of claim 1, further comprising an osteoinductive feature adjacent the flexible wire mesh.

6. The intervertebral spacer of claim 1, wherein the spacer body is porous.

7. The intervertebral spacer of claim 1, further comprising beveled circumferential radial edges which facilitate the application of a desired spreading force to adjacent vertebral bones.

8. The intervertebral spacer of claim 1, further comprising an engagement locus which couples with a corresponding insertion tool to facilitate the same.

9. The intervertebral spacer of claim 8, wherein said engagement locus comprises an axially medial groove into which said insertion tool can be seated.

10. The intervertebral spacer of claim 9, wherein said axially medial groove comprises a constant width, such that said intervertebral spacer may rotate freely within the corresponding insertion tool.

11. The intervertebral spacer of claim 9, wherein said axially medial groove comprises a radially widening groove, such that said intervertebral spacer may be prevented from rotating freely with respect to the corresponding insertion tool by a clamping action thereof, thereby permitting the controlled rotation of the corresponding intervertebral spacer within the intervertebral space by manipulation of the insertion tool.

12. The intervertebral spacer of claim 1, further comprising diametrically tapered upper and lower flexible wire mesh support surfaces.

13. The intervertebral spacer of claim 12, further comprising at least two relative angle designation marks on at least one of said upper and lower flexible wire mesh support surfaces such that a surgeon user may readily visually determine the rotational angle of said intervertebral spacer relative to a known reference.

14. The intervertebral spacer of claim 12, further comprising beveled circumferential radial edges which facilitate the application of a desired spreading force to adjacent vertebral bones.

15. The intervertebral spacer of claim 12, further comprising an engagement locus which couples with a corresponding insertion tool to facilitate the same.

16. The intervertebral spacer of claim 15, wherein said engagement locus comprises an axially medial groove into which said insertion tool can be seated.

17. The intervertebral spacer of claim 16, wherein said axially medial groove comprises a radially widening groove, such that said intervertebral spacer may be prevented from rotating freely with respect to the corresponding insertion tool by a clamping action thereof, thereby permitting the controlled rotation of the corresponding intervertebral spacer within the intervertebral space by manipulation of the insertion tool.