Intervertebral Disc Prosthesis

Abstract

An intervertebral disc prosthesis has two cover plates and a prosthesis core which is connected to one of the cover plates by connection profiles on one of the cover plates which are undercut in a complementary manner and include at least one pair of profile sections which are symmetrical with respect to the AP (anteroposterior) direction of the prosthesis in its implanted position and are arranged at an angle to one another.

1 . An intervertebral disc prosthesis comprising:
 a first cover plate and a second cover plate;   a prosthesis core defined by a generally hexagonal perimeter profile that connects to the first cover plate by a connection profile and an engagement groove;   wherein the generally hexagonal perimeter profile is configured with five substantially straight profile sections: two posterior profile sections that are arranged at an angle to one another, two lateral sections, and an anterior profile section; and   wherein the connection profile formed by the two angled posterior profile sections and the two lateral profile sections is configured with an undercut connection profile that corresponds to a complementary undercut connection profile on the first cover plate.   
     
     
         2 . The intervertebral disc prosthesis of  claim 1 , wherein the connection profile formed by the anterior edge is a groove for receiving an engaging structure. 
     
     
         3 . The intervertebral disc prosthesis of  claim 2 , wherein the engaging structure is a plate. 
     
     
         4 . The intervertebral disc prosthesis of  claim 1 , wherein the angle enclosed by the posterior profile sections is not greater than 150°. 
     
     
         5 . The intervertebral disc prosthesis of  claim 1 , wherein the angle enclosed by the posterior profile sections is approximately 140°. 
     
     
         6 . The intervertebral disc prosthesis of  claim 1 , wherein the prosthesis core has a top surface configured as a slide surface that cooperates with the second cover plate to form a hinge. 
     
     
         7 . The intervertebral disc prosthesis of  claim 5 , wherein the top surface of the prosthesis core has a circumferential contour that is identical to a circumferential contour of the first cover plate. 
     
     
         8 . An intervertebral disc prosthesis comprising:
 a first cover plate and a second cover plate;   a prosthesis core being connected to the first cover plate by at least one pair of connection profiles which are substantially straight and symmetrical with respect to an anterior to posterior direction of implantation and are arranged at an angle to one another, and by a connection profile formed by the anterior edge;   wherein the connection profile formed by the at least one pair of connection profiles is configured with an undercut connection profile that corresponds to a complementary undercut connection profile on the first cover plate; and   wherein the connection profile formed by the anterior edge is a groove for receiving an engaging structure.   
     
     
         9 . The intervertebral disc prosthesis of  claim 8 , wherein the engaging structure is a plate. 
     
     
         10 . The intervertebral disc prosthesis of  claim 8  further comprising two lateral sections which are configured with an undercut connection profile, wherein the two lateral sections are substantially straight and arranged substantially parallel to one another. 
     
     
         11 . The intervertebral disc prosthesis of  claim 8 , wherein the angle enclosed by the posterior profile sections is not greater than 150°. 
     
     
         12 . The intervertebral disc prosthesis of  claim 8 , wherein the angle enclosed by the posterior profile sections is approximately 140°. 
     
     
         13 . The intervertebral disc prosthesis of  claim 8 , wherein the prosthesis core has a top surface configured as a slide surface that cooperates with the second cover plate to form a hinge. 
     
     
         14 . The intervertebral disc prosthesis of  claim 8 , wherein the top surface of the prosthesis core has a circumferential contour that is identical to a circumferential contour of the first cover plate. 
     
     
         15 . A method for assembly of an intervertebral disc prosthesis comprising a first cover plate and a second cover plate, a prosthesis core defined by a generally hexagonal perimeter profile that connects to the first cover plate by a connection profile and an engagement groove, wherein the generally hexagonal perimeter profile is configured with five substantially straight profile sections: two posterior profile sections that are arranged at an angle to one another, two lateral sections, and an anterior profile section; and, wherein the connection profile formed by the two angled posterior profile sections and the two lateral profile sections is configured with an undercut connection profile that corresponds to a complementary undercut connection profile on the first cover plate,
 the method comprising:   inserting the prosthesis core from an open anterior side of the first cover plate;   sliding the prosthesis core from an anterior to posterior direction to fully engage the undercut connection profile with the complementary undercut connection profile of the first cover plate;   inserting an engaging structure into the anterior profile section to secure the prosthesis core to the first cover plate; and   wherein the arrangement of the posterior profile sections at an angle to one another increases rotational stability of the prosthesis core relative to the first cover plate.   
     
     
         16 . The intervertebral disc prosthesis of  claim 15  wherein the engaging structure is a plate. 
     
     
         17 . The intervertebral disc prosthesis of  claim 15 , wherein the angle enclosed by the posterior profile sections is not greater than 150°. 
     
     
         18 . The intervertebral disc prosthesis of  claim 15 , wherein the angle enclosed by the posterior profile sections is approximately 140°. 
     
     
         19 . The intervertebral disc prosthesis of  claim 15 , wherein the prosthesis core has a top surface configured as a slide surface that cooperates with the second cover plate to form a hinge. 
     
     
         20 . The intervertebral disc prosthesis of  claim 19 , wherein the top surface of the prosthesis core has a circumferential contour that is identical to a circumferential contour of the first cover plate.