SPINAL IMPLANT WITH ELLIPTICAL ARTICULATORY INTERFACE

• US 20070191952A1
• Filed: 02/16/2006
• Published: 08/16/2007
• Est. Priority Date: 02/16/2006
• Status: Active Grant

• Current Assignee: CTL Medical Corporation
• Original Assignee: Amedica Corporation
• Inventors: Bernero, John
• Granted Patent: US 8,252,058 B2
• Time in Patent Office: Days
• US Class Current: 623/17.15
• CPC Class Codes: A61F 2/4425 made of articulated components
• CPC Class Codes: A61F 2002/30253 ellipsoidal or ovoid
• CPC Class Codes: A61F 2002/30369 Limited lateral translation of the protrusion within a larger recess
• CPC Class Codes: A61F 2002/30841 Sharp anchoring protrusions for impaction into the bone, e.g. sharp pins, spikes
• CPC Class Codes: A61F 2002/30934 Special articulating surfaces
• 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 2230/0076 ellipsoidal or ovoid

Abstract

A spinal implant prosthesis includes a pair of end plates for affixation to adjacent vertebral bone structures and respectively defining inter-engaged convex and concave articulatory surfaces of elliptical profile. These elliptical articulatory surfaces are elongated in an anterior-posterior direction, and are comparatively shorter in a medial-lateral direction. With this configuration, in response to angular displacement and/or axial rotation, the elliptical surfaces displace in a manner increasing the distance between the adjacent vertebral bone structures, thereby tensioning the prosthesis and producing counteracting forces which urge the components back toward a substantially centered or neutral position. In addition, in the preferred form, the anterior-posterior length of the concave articulatory surface in incrementally greater than the anterior-posterior length of the convex articulatory surface to accommodate a limited range of anterior-posterior translation.

Claims

1. A spinal implant, comprising:

a pair of implant components adapted for affixation respectively to adjacent vertebral structures and including inter-engageable articulatory bearing members;

said bearing members including a convex articulatory surface and a concave articulatory surface both defined by a generally elliptical profile shape in an anterior-posterior direction and a generally elliptical profile shape in a medial-lateral direction.

2. The spinal implant of claim 1 wherein said concave articulatory surface is incrementally elongated relative to said convex articulatory surface in the anterior-posterior direction.

3. The spinal implant of claim 2 wherein said concave articulatory surface substantially matches said convex articulatory surface in the medial-lateral direction.

4. The spinal implant of claim 1 wherein said convex and concave articulatory surfaces are each formed as a segment of an ellipsoid.

5. The spinal implant of claim 1 wherein said convex and concave surfaces are elongated in the anterior-posterior direction relative to the medial-lateral direction.

6. The spinal implant of claim 1 wherein said pair of implant components each include means for affixation to adjacent vertebral structures.

7. A spinal implant, comprising:

a pair of implant components adapted for affixation respectively to adjacent vertebral structures and including inter-engageable articulatory bearing members;

said bearing members respectively including convex and concave articulatory surfaces each defined by a generally elliptical profile shape in an anterior-posterior direction and a generally elliptical profile shape in a medial-lateral direction;

said convex and concave surfaces being elongated in the anterior-posterior direction relative to the medial-lateral direction; and

said concave articulatory surface being incrementally elongated relative to said convex articulatory surface in the anterior-posterior direction, and substantially matching each other in the medial-lateral direction.

8. A spinal implant, comprising:

a pair of implant components adapted for affixation respectively to adjacent vertebral structures and including inter-engageable articulatory bearing members;

said bearing members respectively including convex and concave articulatory surfaces of generally ellipsoid shape having an elongated major axis extending generally in an anterior-posterior direction; and

said concave articulatory surface being incrementally elongated relative to said convex articulatory surface in the anterior-posterior direction.