Posterior prosthetic intervertebral disc

Abstract

A prosthetic intervertebral disc is formed of first and second end plates sized and shaped to fit within an intervertebral space and to be implanted from the back of the patient, thereby decreasing the invasiveness of the procedure. The posterior approach provides for a smaller posterior surgical incision and avoids important blood vessels located anterior to the spine particularly for lumbar disc replacements. The first and second plates are each formed of first, second and third parts are arranged in a first configuration in which the parts are axially aligned to form a low profile device appropriate for insertion through the small opening available in the TLIF or PLIF approaches described above. The three parts of both of the plates rotate and translate with respect to one another in situ to a second configuration or a deployed configuration in which the parts are axially unaligned with each other to provide a maximum coverage of the vertebral end plates for a minimum of insertion profile. Upon deployment of the disc, a height of the disc is increased.

1 . A prosthetic intervertebral disc comprising:
 first and second end plates sized and shaped to fit within an intervertebral space, each end plate having a vertebral contacting surface and an inner surface;   a first bearing surface on an inner surface of the first end plate and a second bearing surface on an inner surface of the second end plate;   a mobile core configured to be received between the first and second bearing surfaces and arranged to allow articulation and rotation between the first and second plate;   wherein the first and second plates are each formed of first, second and third interconnected parts having a first configuration in which the parts are axially aligned and a second configuration in which the parts are axially unaligned with each other, the first and second plates deployed in situ from the first configuration to the second configuration by rotation of the parts over one another, and wherein the deployment from the first configuration to the second configuration increases a height of the disc.   
     
     
         2 .- 6 . (canceled) 
     
     
         7 . The disc of  claim 1 , wherein first configuration comprises a substantially linear arrangement. 
     
     
         8 . The disc of  claim 7 , wherein the second configuration comprises a substantially H-shaped arrangement. 
     
     
         9 . The disc of  claim 7 , wherein the disc in the first configuration has a height and width of less than 12 mm. 
     
     
         10 . A prosthetic intervertebral disc comprising:
 first and second end plates sized and shaped to fit within an intervertebral space, each end plate having a vertebral contacting surface and an inner surface;   a first bearing surface on an inner surface of the first end plate and a second bearing surface on an inner surface of the second end plate, the first and second bearing surfaces opposed to one another;   wherein the first and second end plates are each formed of at least two parts having a first configuration in which the parts are substantially axially aligned and a second configuration in which the parts are axially unaligned with each other;   a mobile core configured to be received between the first and second bearing surfaces and arranged to allow articulation and rotation between the first and second end plates; and   a track formed in the first and second end plates, the track configured to allow the mobile core to move from a first position outside of the bearing surfaces to a position between the bearing surfaces, wherein the movement of the mobile core from the first position to the second position increases a height of the disc.   
     
     
         11 . The disc of  claim 10 , wherein the at least two parts comprise first, second and third parts arranged with the second part interconnecting the first and third parts. 
     
     
         12 . The disc of  claim 11 , wherein the first and third parts are arranged to pivot on opposite ends of the second part during deployment. 
     
     
         13 . The disc of  claim 10 , wherein first configuration comprises a substantially linear arrangement. 
     
     
         14 . The disc of  claim 13 , wherein the second configuration comprises a substantially H-shaped arrangement. 
     
     
         15 . The disc of  claim 10 , wherein the disc in the first configuration has a height and width of less than 12 mm. 
     
     
         16 . The disc of  claim 10 , wherein the disc in the second configuration has a height of at least 1.5 times a height in the first configuration. 
     
     
         17 . The disc of  claim 1 , wherein the disc in the second configuration has a height of at least 1.5 times a height in the first configuration. 
     
     
         18 . A method of deploying a prosthetic intervertebral disc, the method comprising:
 providing a prosthetic intervertebral disc having first and second end plates each having a vertebral contacting surface and an inner surface, a first bearing surface on an inner surface of the first end plate and a second bearing surface on an inner surface of the second end plate, the first and second bearing surfaces arranged to allow articulation and rotation between the first and second plates, wherein the first and second plates are each formed of first, second and third parts;   inserting the intervertebral disc between two vertebrae in a configuration in which the first, second and third parts of each of the plates are axially aligned; and   deploying the first and second plates in situ from the first configuration to a second configuration in which the parts are axially unaligned with each other by both rotation and sliding of the parts over one another, wherein the deployment from the first configuration to the second configuration increases a height of the disc.   
     
     
         19 . The method of  claim 18 , wherein the first, second and third parts are arranged with the second part interconnecting the first and third parts. 
     
     
         20 . The method of  claim 19 , wherein opposite ends of the second part slide along the first and third parts during deployment. 
     
     
         21 . The method of  claim 20 , wherein the opposite ends of the second part slide in elongated tracks on the second and third parts to increase the height of the disc in a direction perpendicular to the direction of sliding. 
     
     
         22 . A method of deploying a prosthetic intervertebral disc, the method comprising:
 providing a prosthetic intervertebral disc comprising first and second end plates and a mobile core arranged to allow articulation and rotation between the first and second plates, wherein the first and second plates are each formed of at least two parts;   inserting the intervertebral disc between two vertebrae in a configuration in which the first, second and third parts of each of the plates are substantially axially aligned;   deploying the first and second plates in situ from the first configuration to a second configuration in which the parts are axially unaligned with each other; and   moving the mobile core along a track between the end plates, wherein the movement of the mobile core from the first position to the second position increases a height of the disc.   
     
     
         23 . The method of  claim 22 , wherein the track is formed in inner surfaces of the first and second end plates and is configured to allow the mobile core to move from a first position outside of bearing surfaces of the end plates to a position between the bearing surfaces of the end plates. 
     
     
         24 . The method of  claim 22 , wherein the second configuration comprises a substantially H-shaped arrangement. 
     
     
         25 . The method of  claim 22 , wherein the disc in the first configuration has a height and width of less than 12 mm. 
     
     
         26 . The method of  claim 22 , wherein the disc in the second configuration has a height of at least 1.5 times a height in the first configuration. 
     
     
         27 . The method of  claim 22 , wherein the at least two parts comprise first, second and third parts arranged with the second part interconnecting the first and third parts. 
     
     
         28 . The disc of  claim 1 , wherein the mobile core allows articulation in an anterior/posterior direction and in a lateral direction.