Prosthetic intervertebral disc

• US 5,865,845 A
• Filed: 03/05/1996
• Issued: 02/02/1999
• Est. Priority Date: 03/05/1996
• Status: Expired due to Fees

• Current Assignee: John S. Thalgott
• Original Assignee: John S. Thalgott
• Inventors: Thalgott, John S.
• Primary Examiner(s): BRITTINGHAM, DEBRA
• Application Number:
  US08/609,593
• Time in Patent Office: 1,064 Days
• Field of Search: 623/17, 623/16, 606/60, 606/61
• US Class Current: 623/17.16
• 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 2/442 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 2/4603 for insertion or extraction of endoprosthetic joints or of accessories thereof
• CPC Class Codes: A61F 2/4611 of spinal prostheses
• CPC Class Codes: A61F 2002/30115 circular-O-shaped
• CPC Class Codes: A61F 2002/30158 trapezoidal
• CPC Class Codes: A61F 2002/30187 D-shaped or half-disc-shaped
• CPC Class Codes: A61F 2002/30228 Cylinders of elliptical or oval basis
• CPC Class Codes: A61F 2002/3023 wedge-shaped cylinders
• CPC Class Codes: A61F 2002/30261 parallelepipedal
• CPC Class Codes: A61F 2002/30266 wedge-shaped parallelepipeds
• 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 2002/30772 Apertures or holes, e.g. of circular cross section
• CPC Class Codes: A61F 2002/30777 Oblong apertures
• CPC Class Codes: A61F 2002/30795 Blind bores, e.g. of circular cross-section
• CPC Class Codes: A61F 2002/30843 Pyramidally-shaped
• CPC Class Codes: A61F 2002/30892 : parallel
• CPC Class Codes: A61F 2002/4635 : using minimally invasive surgery
• CPC Class Codes: A61F 2220/0025 : Connections or couplings between prosthetic parts, e.g. between modular parts; Connecting elements
• CPC Class Codes: A61F 2230/0006 : circular
• CPC Class Codes: A61F 2230/0026 : trapezoidal
• CPC Class Codes: A61F 2230/0034 : D-shaped
• CPC Class Codes: A61F 2230/0069 : cylindrical
• CPC Class Codes: A61F 2230/0082 : parallelepipedal
• CPC Class Codes: A61F 2310/00023 : Titanium or titanium-based alloys, e.g. Ti-Ni alloys
• CPC Class Codes: A61F 2310/00293 : containing a phosphorus-containing compound, e.g. apatite

Abstract

The invention provides a spinal disc implant comprising a ring shaped body including a first pair of opposed substantially parallel sides spaced apart by a second pair of opposed sides to define a central bore. A first one of the second pair of sides defines a substantially arcuate curve joining a first end of the first pair of sides. A second one of the second pair of opposed sides substantially linearly joins a second end of the first pair of sides. The upper and lower surfaces of the ring shaped body 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 may have a porous hydroxyapatite block shaped to fill the interior space. The porous hydroxyapatite substance helps the prosthesis integrate into the vertebral structure by allowing one grow into the pores.

Claims

1. A spinal disc implant comprising a ring-shaped body including a first pair of opposed substantially parallel sides spaced apart by a second pair of opposed sides to define a central bore, a first one of the second pair of sides defining a substantially arcuate curve joining a first end of the first pair of sides, a second one of the second pair of opposed sides joining a second end of the first pair of sides, upper and lower surfaces of the ring-shaped body having a plurality of teeth extending therefrom along a perimeter of the implant for engaging the adjacent vertebral bodies, the implant being made of a bicompatible metal;

the first and second sides tapering from the second end to the first end and conforming to a curvature of a vertebral body on which the implant rests.

2. A spinal disc implant in accordance with claim 1 wherein the ring-shaped body is substantially oval.

3. A spinal disc implant in accordance with claim 1 wherein the ring-shaped body is substantially D-shaped.

4. A spinal disc implant in accordance with claim 3 wherein the biocompatible metal is titanium or alloys thereof.

5. A spinal disc implant in accordance with claim 3 wherein the central bore includes a porous hydroxyapatite block shaped to fill the central bore.

6. A spinal disc implant in accordance with claim 5 wherein the upper and lower surfaces of the ring-shaped body are convexly curved to mate with surfaces of adjacent endplates of vertebrae between which the implant is inserted.

7. A spinal disc implant in accordance with claim 5, wherein the implant includes a hole formed in the ring-shaped body, and further comprising a screw inserted in the hole for fixing the hydroxyapatite block in the central bore of the implant.

8. A spinal disc implant in accordance with claim 3 wherein the upper and lower surfaces of the ring-shaped body are curved to mate with adjacent endplates of vertebrae between which the implant is inserted.

9. A spinal disc implant having a generally elongated D-shaped body, the body tapering in thickness from a first end to a second end along first and second faces thereof, a degree of taper and thickness to allow the implant to fit within a cavity created by removal of a diseased or damaged vertebral disc and defined by an angle formed by adjacent vertebral bodies from between which the vertebral disc is removed, said spinal disc implant being of titanium or an alloy thereof and having a central bore open to first and second faces thereof being filled by a porous hydroxyapatite block shaped to substantially fill the central bore, the spinal disc implant additionally having a plurality of teeth projecting along the perimeter of the D-shaped body on the first and second faces for engaging bony and soft tissue of adjacent vertebrae, the teeth encircling the hydroxyapatite block and the second face convexly curved to mate with an overlying or underlying surface of a vertebral body on which the implant rests.