Artificial disc prosthesis
First Claim
1. An artificial intervertebral disc prosthesis having an anterior portion and a posterior portion, comprising:
- a first endplate having an upper surface and a lower relatively flat, uninterrupted surface;
a second endplate having an upper surface and a lower surface, wherein an axis perpendicular to said first endplate and said second endplate is a longitudinal axis;
a visco-elastic cushion interposed between and adhered to said first and second endplates, wherein said visco-elastic cushion is annular and comprises a cavity therein defining a visco-elastic cushion internal space bounded by a visco-elastic cushion internal surface substantially parallel to said longitudinal axis;
a first projection extending from said lower surface of said first endplate terminating in a first distal end, said first projection having at least one side wall parallel to said visco-elastic cushion internal surface;
a second projection extending from said upper surface of said second endplate and into said cavity and substantially aligned with said first projection, said second projection having at least one side wall parallel to said visco-elastic cushion internal surface, said second projection terminating at a second distal end to form, in an unloaded condition, a gap between said first distal end and said second distal end, said gap having a predetermined dimension; and
wherein direct contact between first distal end of said first projection and said second distal end of said second projection limits said first endplate and said second endplate from moving relatively closer to one another.
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Accused Products
Abstract
A visco-elastic motion-limiting artificial intervertebral disc prosthesis is provided that mimics the physiologic function of a normal spinal disc. The disc comprises upper and lower endplates having therewithin channels or openings for optionally receiving one or more motion-limiting members fitted on each end with an enlarged portion. One or more compression stops is provided between the upper and lower endplates. Additionally, an elastomeric cushion is disposed between the endplates and surrounds the motion-limiting members. Also, force transducers and microelectronics can be utilized to provide data to the surgeon or the patient regarding the load state of the disc.
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Citations
36 Claims
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1. An artificial intervertebral disc prosthesis having an anterior portion and a posterior portion, comprising:
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a first endplate having an upper surface and a lower relatively flat, uninterrupted surface; a second endplate having an upper surface and a lower surface, wherein an axis perpendicular to said first endplate and said second endplate is a longitudinal axis; a visco-elastic cushion interposed between and adhered to said first and second endplates, wherein said visco-elastic cushion is annular and comprises a cavity therein defining a visco-elastic cushion internal space bounded by a visco-elastic cushion internal surface substantially parallel to said longitudinal axis; a first projection extending from said lower surface of said first endplate terminating in a first distal end, said first projection having at least one side wall parallel to said visco-elastic cushion internal surface; a second projection extending from said upper surface of said second endplate and into said cavity and substantially aligned with said first projection, said second projection having at least one side wall parallel to said visco-elastic cushion internal surface, said second projection terminating at a second distal end to form, in an unloaded condition, a gap between said first distal end and said second distal end, said gap having a predetermined dimension; and wherein direct contact between first distal end of said first projection and said second distal end of said second projection limits said first endplate and said second endplate from moving relatively closer to one another. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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20. An artificial intervertebral disc prosthesis having an anterior portion and a posterior portion, comprising:
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a first endplate having an upper surface and a lower relatively flat, uninterrupted surface; a second endplate having an upper surface and a lower surface, wherein an axis perpendicular to said first endplate and said second endplate is a longitudinal axis; a projection extending from said upper surface of said second endplate toward said first endplate, said projection being at least partially cylindrical and having at least one side wall parallel to a longitudinal axis of said prosthesis, said projection terminating at a distal end to form a gap between said distal end and said first endplate lower surface, said gap having a predetermined dimension; and a visco-elastic cushion interposed between and adhered to said first and second endplates having a cavity for receiving said projection; wherein said distal end of said projection is substantially planar; and wherein direct contact between said projection and said first endplate stops compressive motion but allows at least some amount of shear motion. - View Dependent Claims (21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32)
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33. An artificial intervertebral disc prosthesis having an anterior portion and a posterior portion, comprising:
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a first endplate having an upper surface and a lower relatively flat, uninterrupted surface; a second endplate having an upper surface and a lower surface, wherein an axis perpendicular to said first endplate and said second endplate is a longitudinal axis; a projection extending from said upper surface of said second endplate toward said first endplate, said projection being at least partially cylindrical and having at least one side wall parallel to a longitudinal axis of said prosthesis, said projection terminating at a distal end to form a gap between said distal end and said first endplate lower surface, said gap having a predetermined dimension; and a visco-elastic cushion interposed between and adhered to said first and second endplates having a cavity for receiving said projection; wherein direct contact between said distal end of said projection and said first endplate permits at least some motion in a direction perpendicular to a direction that brings said first endplate and said second endplate closer to each other.
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34. An artificial intervertebral disc prosthesis comprising:
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a first endplate having a first surface for engaging a vertebra and a second surface opposite said first surface; a second endplate having a first surface for engaging a different vertebra and a second surface opposite said first surface; a longitudinal axis defined between said first endplate and said second endplate and normal thereto; an annular polymeric member having an upper surface and a lower surface and having a cavity defining a polymeric member internal space that is bounded along said longitudinal axis by said second surface of said first endplate and by said second surface of said second endplate, and is bounded in a plane normal to said longitudinal axis by a polymeric member internal surface; a projection from said second surface of said second endplate having a distal end located within said polymeric member internal space, said distal end having a contact surface thereon for directly contacting a portion of said second surface of said first endplate; wherein said upper surface and said lower surface of said annular polymeric member are adhered to, respectively, said second surface of said first endplate at a first adhesion layer and to said second surface of said second endplate at a second adhesion layer; wherein at least one of said first adhesion layer and said second adhesion layer is parallel to said contact surface of said projection. - View Dependent Claims (35, 36)
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Specification