Disc prosthesis

• US 20030023312A1
• Filed: 09/27/2002
• Published: 01/30/2003
• Est. Priority Date: 08/15/2000
• Status: Active Grant

• Current Assignee: Depuy Spine Incorporated (Johnson & Johnson)
• Original Assignee: Depuy Spine Incorporated (Johnson & Johnson)
• Inventors: Thalgott, John S.
• Granted Patent: US 7,226,480 B2
• Time in Patent Office: Days
• US Class Current: 623/17.16
• 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 2/4455 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 2/4465 having a circular or kidney shaped cross-section substantially perpendicular to the axis of the spine
• CPC Class Codes: A61F 2/4611 of spinal prostheses
• CPC Class Codes: A61F 2002/30187 D-shaped or half-disc-shaped
• CPC Class Codes: A61F 2002/30507 using a threaded locking member, e.g. a locking screw or a set screw
• CPC Class Codes: A61F 2002/30593 hollow
• CPC Class Codes: A61F 2002/30616 Sets comprising a plurality of prosthetic parts of different sizes or orientations
• CPC Class Codes: A61F 2002/30733 Inserts placed into an endoprosthetic cavity, e.g. for modifying a material property
• CPC Class Codes: A61F 2002/30777 Oblong apertures
• CPC Class Codes: A61F 2002/30787 inclined obliquely with respect to each other
• CPC Class Codes: A61F 2002/30789 perpendicular with respect to each other
• CPC Class Codes: A61F 2002/30843 Pyramidally-shaped
• CPC Class Codes: A61F 2002/30892 parallel
• CPC Class Codes: A61F 2220/0025 Connections or couplings between prosthetic parts, e.g. between modular parts; Connecting elements
• CPC Class Codes: A61F 2230/0034 D-shaped
• CPC Class Codes: A61F 2310/00023 Titanium or titanium-based alloys, e.g. Ti-Ni alloys
• CPC Class Codes: A61F 2310/00179 Ceramics or ceramic-like structures
• CPC Class Codes: A61F 2310/00293 containing a phosphorus-containing compound, e.g. apatite

Abstract

The invention provides a spinal disc implant comprising two side walls which are opposed and substantially parallel spaced apart by a front wall and a back wall to define an interior space. The side walls define substantially elliptical curves joining the front and back walls. The front wall is also curved and the back wall may be either curved or straight. The walls may have openings or holes which may be circular or elliptical in shape. The upper and lower edges of the implant have a plurality of teeth extending therefrom for engaging adjacent vertebrae. The implant is made of a biocompatible metal such as titanium or an alloy thereof, and the first and second sides tapering from the second end to the first end. The interior space has a porous hydroxyapatite block shaped to fill the interior space. The porous hydroxyapatite substance helps the prosthesis integrate into the vertebral structure by allowing into the pores.

Claims

1. An implant of a biocompatible metallic body having a front wall, a rear wall, and two side walls extending therebetween to define a substantially D-shaped interior space, and wherein each side wall defines a substantially arcuate curve joining one end of the front wall and one end of the rear wall, and wherein each wall contains at least one opening therein, the upper and lower surfaces of the two side walls having a plurality of teeth extending therefrom for engaging adjacent vertebral bodies, the implant being made of a biocompatible metal, the side walls tapering in height from the rear wall to the front wall;

wherein the upper and lower surfaces of the front and rear walls each lack teeth, and have a height substantially similar to that of a portion of the side wall adjacent the front and rear walls.

2. A spinal disc implant in accordance with claim 1, wherein the height of the rear wall ranges from about 11 mm to about 15 mm, and the height of the front wall ranges from about 8 mm to about 12 mm.

3. A spinal disc implant in accordance with claim 2, wherein the difference in height between the rear wall of the implant and the front wall of the implant is about 3 mm.

4. A spinal disc implant in accordance with claim 1 wherein the rear wall of the implant has a notch in an upper and lower edge thereof.

5. A spinal disc implant in accordance with claim 1 wherein the biocompatible metallic body is titanium or an alloy thereof.

6. A spinal disc implant in accordance with claim 5 wherein the interior space includes a porous hydroxyapatite block shaped to be held by the implant within the interior space.

7. A spinal implant in accordance with claim 1 wherein upper and lower surfaces of the implant are curved to mate with a domed surface of adjacent end plates of vertebrae between which the implant is inserted.

8. A spinal disc implant in accordance with claim 7, wherein the upper and lower edges of the implant are convexly curved to mate with the surface of adjacent end plates of vertebrae between which the implant is inserted.

9. An implant of a biocompatible metal for replacing a diseased spinal disk, comprising:

a generally D-shaped body, the body including a curved front wall, a substantially straight rear wall, and a pair of spaced apart arcuate side walls connecting the front and rear walls, the side walls including a plurality of teeth on upper and lower surfaces thereof;

the front and rear walls lacking teeth and having a height equal to that of the side walls less approximately twice the height of the teeth;

the rear wall also having a notch on an upper and lower edge thereof for engaging an insertion instrument;

the side walls sloping from the front wall to the rear wall such that the height of the front wall exceeds the height of the rear wall by about 3 mm.

10. A spinal disc implant in accordance with claim 9, wherein the height of the front wall ranges from about 8 mm to about 12 mm, and the height of the rear wall ranges from about 11 mm to about 15 mm.

11. A spinal disc implant in accordance with claim 10, wherein the biocompatible metal is titanium or an alloy thereof.

12. A spinal disc implant in accordance with claim 11, wherein the implant includes a plurality of openings spaced around the periphery thereof.