Tapered prosthetic spinal disc nucleus
AssigneeRaymedica, Inc.
InventorsCharles D. Ray, Robert L. Assell
Life of this patent
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Abstract
A wedge-shaped prosthetic spinal disc nucleus including a hydrogel core surrounded by a constraining jacket. The hydrogel core is preshaped to form the wedge shape in a hydrated state. The constraining jacket is flexible, but substantially inelastic and is configured to prevent the hydrogel core from conforming to an anulus upon hydration. The prosthetic spinal disc nucleus corresponds generally to anatomical variations in disc space geometry, generally defined by separable areas or compartments, thus improving performance. In one preferred embodiment, the prosthetic spinal disc nucleus includes a radiopaque marker for indicating a location and orientation following implant.
Claims29
A prosthetic spinal disc nucleus for implantation into a nucleus cavity of a spinal disc, the nucleus cavity defined by an opposing pair of vertebral bodies and an anulus, the prosthetic spinal disc nucleus comprising:
- a formed hydrogel core configured to expand from a dehydrated state to a hydrated state, the hydrogel core being wedge-shaped prior to implant in at least the hydrated state;
- and
- a constraining jacket surrounding the hydrogel core, the constraining jacket being flexible but substantially inelastic, and having a generally fixed maximum volume less than a volume of a nucleus cavity such that the constraining jacket is configured to prevent the hydrogel core from conforming to an anulus upon hydration.
A prosthetic spinal disc nucleus for implantation into a nucleus cavity of a spinal disc, the nucleus cavity defined by an opposing pair of vertebral bodies, forming opposing end plates, and an anulus, the prosthetic spinal disc nucleus comprising:
- a hydrogel core configured to expand from a dehydrated state to a hydrated state, the hydrogel core being preshaped to have, prior to implant and in the hydrated state, a tapered height corresponding generally to an anatomical variation in height of a nucleus cavity;
- and
- a constraining jacket surrounding the hydrogel core, the constraining jacket having a generally fixed maximum volume less than a volume of a nucleus cavity and being sized to prevent the hydrogel core from conforming to an anulus upon hydration.
A method of manufacturing a prosthetic spinal disc nucleus for implantation into a nucleus cavity of a spinal disc, the nucleus cavity defined by an opposing pair of vertebral bodies and an anulus, the method including:
- forming a hydrogel core to an approximate wedge shape prior to implant, the hydrogel core being formed to expand from a dehydrated state to a hydrated state;
- providing a substantially inelastic constraining jacket;
- dehydrating the hydrogel core;
- and
- inserting the hydrogel core into the constraining jacket.
Dependencies are inferred from the claim text.