Intervertebral disk arthroplasty device

An intervertebral disk arthroplasty device adapted to replace a disk between a first vertebra and a second vertebra in a spine, said arthroplasty device comprising:

• a first member having a first joint surface, a top surface opposite said first joint surface, a first posterior end and a first anterior end;
• a second member having a second joint surface facing said first joint surface, a bottom surface opposite said second joint surface, and second posterior and anterior ends juxtaposed with corresponding ones of said first posterior and anterior ends;
• a first insert cup having a first receiving surface for receiving said top surface therein, and a first engaging surface opposite said first receiving surface for engaging the first vertebra;
• a second insert cup having a second receiving surface for receiving said bottom surface therein, and a second engaging surface opposite said second receiving surface for engaging the second vertebra;
• and
• retaining ribs formed within said top and bottom surfaces and extending parallel with the anterior and posterior ends of said first and second insert cups along a substantial portion of said top and bottom surfaces, said retaining ribs being configured to permit movement of said disk arthroplasty device in the first direction and to resist movement of said disk arthroplasty device in an opposite direction.

An intervertebral disk arthroplasty adapted to replace a disk between a first vertebra and a second vertebra in a spine, said arthroplasty comprising:

• a first member having a first surface for engaging the first vertebra, an opposite first joint surface, a posterior end and a first anterior end, said ends defining a transverse midline therebetween, said midline being equidistant from said first posterior end and said first anterior end;
• a second member having a second surface for engaging the second vertebra, an opposite second joint surface facing said first joint surface, and second posterior and anterior ends juxtaposed with corresponding ones of said first posterior and anterior ends;
• a joint between said first and second members to permit relative rotation between said first member and said second member about a first axis parallel to said transverse midline and a second axis perpendicular to said first axis, said joint including;
• a first, second and third ball portion defined in said first joint surface of said first member, said ball portions having circular cross sections along an axis parallel to said transverse midline, said first ball portion having a larger radius than said second and third ball portions, said second and third ball portions having equal radii and being disposed on opposite sides of said first ball portion, said ball portions being disposed radially about said firsts axis;
• and
• a socket portion defined in said second joint surface substantially complementary to said ball portions in said first joint surface and configured to receive said ball portions therein;
• a first insert cup for inserting the surface opposite said first joint surface of said first member therein;
• and
• a second insert cup for inserting the surface opposite said second joint surface of said second member therein;
• each of said insert cups having a surface for engaging a respective vertebra of the first and second vertebra;
• and
• said engaging surfaces being disposed convexly about said second axis.