US 4,863,476 AGranted

Spinal implant

OwnerJohn A. N. Shepperdinventor

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Abstract

A apinal implant has an elongate body which is divided into two portions with mutually opposed contact surfaces and is for insertion into the joint space between two adjacent vertebrae. A cam device or cam devices are movable between the contact surfaces to expand or increase the spacing between the body portions so as to increase the spacing between the adjacent vertebrae. The implant has a porous external surface to facilitate bore and cartilage tissue growth therein. Alternatively, the external surface is smooth and coated with a bioactive material such as a hydroxyapatite, for example, tricalcium phospahte. In both instances bone, cartilage tissue and external surfaces of the implant are fused together to prevent migration of the implant. Advantageously, insertion of the implant requires a minimum incision in skin and cartilage tissue.

Claims3

Dependent claims

A spinal implant for insertion in the joint space between adjacent vertebrae comprising:

an elongated member divided longitudinally into two body portions which are movable between an open position, in which an external surface of each body portion is adapted to engage an adjacent vertebrae, and as closed position in which opposign adjacent flat contact surfaces on each said body portion abut each other, said body portions having a recess in eah of said flat contact surfaces so that said recesses define, in said closed position, an elongated aperture located centrally along the spinal implant;
and
an expansion means adapted to be disposed within said aperture so as to move said body portions between said open and closed positions and adjust the joint spacing between adjacent vertebrae, said expansion means having cam means that engage oppositely pitched thread patterns on end portions of a rod assembly so that the rotation of said rod assembly causes the cam means to move in unison along said rod assembly and between said contact surfaces so as cause said body surfaces to be moved.

Dependencies are inferred from the claim text.

Facts

Application: 07/090,610Filed 28 Aug 1987
Priority: GB 862093729 Aug 1986
Granted: 5 Sep 1989
Term ends: Not estimatedThe source records don’t support an estimate.

Classification27 codes

A61F 2/4611
For insertion or extraction of endoprosthetic joints or of accessories thereof: of spinal prostheses
A61F 2/4455
For the spine, e.g. vertebrae or spinal discs: for the fusion of spinal bodies, e.g. intervertebral fusion of adjacent spinal bodies, e.g. fusion…
A61F 2/446
For the fusion of spinal bodies, e.g. intervertebral fusion of adjacent spinal bodies, e.g. fusion cages: having a circular or elliptical…
A61F 2/30724
Accessories: spacers for centering an implant in a bone cavity, e.g. in a cement-receiving cavity