Ramp-shaped intervertebral implant

• US 6,530,955 B2
• Filed: 05/18/2001
• Issued: 03/11/2003
• Est. Priority Date: 06/08/1999
• Status: Expired due to Fees

• Current Assignee: Osteotech Incorporated (Medtronic Plc)
• Original Assignee: Osteotech Incorporated (Medtronic Plc)
• Inventors: Morris, John W., Martz, Erik O., Daugherty, Mark, Kaes, David R., Boyce, Todd M., Shimp, Lawrence A., Boyle, John W.
• Primary Examiner(s): Isabella, David J.
• Application Number:
  US09/861,369
• Publication Number:
  US 20020026242A1
• Time in Patent Office: 662 Days
• Field of Search: 623/17.11, 623/17.16, 606/61
• US Class Current: 623/17.11
• CPC Class Codes: A61F 2/28 Bones joints A61F2/30
• CPC Class Codes: A61F 2/30771 applied in original prostheses, e.g. holes or grooves
• CPC Class Codes: A61F 2/30965 Reinforcing the prosthesis by embedding particles or fibres during moulding or dipping
• 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 2/447 substantially parallelepipedal, e.g. having a rectangular or trapezoidal cross-section
• CPC Class Codes: A61F 2/4603 for insertion or extraction of endoprosthetic joints or of accessories thereof
• CPC Class Codes: A61F 2/4611 of spinal prostheses
• CPC Class Codes: A61F 2002/2817 Bone stimulation by chemical reactions or by osteogenic or biological products for enhancing ossification, e.g. by bone morphogenetic or morphogenic proteins [BMP] or by transforming growth factors [TGF]
• CPC Class Codes: A61F 2002/2825 Femur
• 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 2002/30112 Rounded shapes, e.g. with rounded corners
• CPC Class Codes: A61F 2002/30115 circular-O-shaped
• CPC Class Codes: A61F 2002/30131 horseshoe- or crescent- or C-shaped or U-shaped
• CPC Class Codes: A61F 2002/30153 rectangular
• CPC Class Codes: A61F 2002/30158 trapezoidal
• CPC Class Codes: A61F 2002/3023 wedge-shaped cylinders
• CPC Class Codes: A61F 2002/30235 tubular, e.g. sleeves
• CPC Class Codes: A61F 2002/30237 partial tubes
• CPC Class Codes: A61F 2002/30266 wedge-shaped parallelepipeds
• CPC Class Codes: A61F 2002/3028 : polyhedral different from parallelepipedal and pyramidal
• CPC Class Codes: A61F 2002/30324 : differing in thickness
• 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 2002/30785 : parallel
• CPC Class Codes: A61F 2002/30789 : perpendicular with respect to each other
• CPC Class Codes: A61F 2002/3082 : Grooves
• CPC Class Codes: A61F 2002/30836 : knurled
• CPC Class Codes: A61F 2002/30843 : Pyramidally-shaped
• CPC Class Codes: A61F 2002/30904 : serrated profile, i.e. saw-toothed
• CPC Class Codes: A61F 2002/30952 : using CAD-CAM techniques or NC-techniques
• 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 2002/4649 : Bone graft or bone dowel harvest sites
• CPC Class Codes: A61F 2230/0004 : Rounded shapes, e.g. with rounded corners
• CPC Class Codes: A61F 2230/0006 : circular
• CPC Class Codes: A61F 2230/0013 : Horseshoe-shaped, e.g. crescent-shaped, C-shaped, U-shaped
• 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 2230/0069 : cylindrical
• CPC Class Codes: A61F 2230/0082 : parallelepipedal
• CPC Class Codes: A61F 2250/0036 : differing in thickness
• 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 2310/00131 : Tantalum or Ta-based alloys
• CPC Class Codes: A61F 2310/00293 : containing a phosphorus-containing compound, e.g. apatite
• CPC Class Codes: A61F 2310/00359 : Bone or bony tissue

Abstract

A ramp-shaped intervertebral implant is disclosed. The implant has a body having a first end, a second end, a top surface and a bottom surface. At least one of the top and bottom surfaces is tapered and converges towards the second end of the body. An opening extends through the body and has one end opening onto the top surface of the implant and the other end opening onto the bottom surface of the implant. The implant can be formed from the diaphysis or metaphysis of a long bone, wherein the intramedullary canal of the long bone defines the opening. Alternately, the implant can be made from any biocompatible material having the requisite strength requirement.

Claims

1. A ramp-shaped intervertebral implant comprising:

a body constructed from bone and having a first end, a second end and top and bottom surfaces, at least one of the top and bottom surfaces being tapered and converging towards the second end of the body, at least one of the top and bottom surfaces having a plurality of protrusions thereon, the protrusions defining substantially V-shaped elongated, parallel grooves, and at least one opening extending through the body having one end opening onto the top surface and one end opening onto the bottom surface, wherein the first end of the implant includes an elongated slot and a bore formed in a base of the slot, the elongated slot and the bore being configured to engage an implant insertion tool.

2. A ramp-shaped intervertebral implant according to claim 1, wherein the protrusions include a series of ridges.

3. A ramp-shaped intervertebral implant according to claim 2, wherein the implant includes a pair of substantially parallel side walls, each ridge of the series of ridges having a longitudinal axis that extends in a direction substantially perpendicular to the side walls.

4. A ramp-shaped intervertebral implant according to claim 1, wherein the implant is constructed from the diaphysis or metaphysis of a long bone and the intramedullary canal of the long bone defines the bore.

5. A ramp-shaped intervertebral implant according to claim 1, wherein the implant is formed from bone which is at least partially demineralized.

6. A ramp-shaped intervertebral implant according to claim 1, wherein the implant has a substantially rectangular configuration.

7. A ramp-shaped intervertebral implant according to claim 1, wherein protrusions are formed on both the top and bottom surfaces.

8. A ramp-shaped intervertebral implant according to claim 1, wherein at least one of the top and bottom surfaces is convex.

9. A method for forming a ramp-shaped implant comprising the following steps:

a) making a transverse cut across a long bone having an intramedullary canal to form a cortical ring;

b) machining at least one of top and bottom surfaces of the cortical ring such that the top and bottom surfaces of the cortical ring converge towards one another in a direction towards a second end of the cortical ring, the intramedullary canal of the long bone defining an opening having one end opening onto the top surface of the cortical ring and having a second end opening onto the bottom surface of the cortical ring;

c) machining at least one of the top and bottom surfaces of the cortical ring to form a plurality of protrusions thereon the plurality of protrusions defining a plurality of substantially V-shaped elongated, parallel grooves; and

;

d) forming an elongated slot and a cylindrical bore in a first end of the implant.

10. A method for forming a ramp-shaped implant according to claim 9, wherein the protrusions include a series of ridges.

11. A method for forming a ramp-shaped implant according to claim 10, wherein the machining steps further include use of a three-dimensional milling machine.

12. A method for forming a ramp-shaped implant according to claim 11, wherein steps b) and c) are performed simultaneously using the three-dimensional milling machine.

13. A method for forming a ramp-shaped implant according to claim 9, further including the step of partially demineralizing the bone.

14. A method for forming a ramp-shaped implant according to claim 13, wherein the step of partially demineralizing the bone occurs before the cortical ring is cut from the long bone.

15. A method for forming a ramp-shaped implant according to claim 9, further including the step of:

d) machining sidewalls of the cortical ring to form an implant having a substantially rectangular configuration.

16. A method for forming a ramp-shaped implant according to claim 9, further including the step of:

d) infusing bone growth material into the bone.

17. A method of forming a ramp-shaped implant according to claim 9, further including the step of:

d) forming a plurality of perforations in surfaces of the implant other than the top and bottom surfaces.

18. A method of forming a ramp-shaped implant according to claim 9, wherein at least one of the top and bottom surfaces is convex.