Intervertebral spacer device having a circumferentially buried wire mesh endplate attachment device

Abstract

An artificial disc having a pair of opposing baseplates, for seating against opposing vertebral bone surfaces, separated by a ball and socket joint that includes a solid ball mounted to protrude from one of the baseplates. The ball is captured within a curvate socket formed in a peak of a convex structure integral with the other of the baseplates. The socket is formed by opposing curvate pockets, one on the convex structure and one on a retaining cap that is secured to the other of the baseplates. The ball rotates and angulates in the socket. The ball and socket joint therefore permits the baseplates to rotate and angulate relative to one another.

1 . An intervertebral implant comprising:
 a lower baseplate having an outer vertebral body contact surface and an inner surface having a spherical portion;   a housing having an articulation surface having a protrusion extending therefrom;   an articulation member having a spherical outer surface with a recess therein, the recess having a stop surface, the spherical outer surface of the articulation member contacting both the articulation surface of the housing and the spherical portion of the inner surface of the lower baseplate; and   a upper baseplate having an outer vertebral body contact surface and an inner surface coupled to the articulation member,   wherein articulation of the lower and upper baseplates with respect to one another is limited when the protrusion of the articulation surface of the housing contacts the stop surface of the recess of the articulation member.   
     
     
         2 . The intervertebral implant of  claim 1 , wherein the inner surface of the upper baseplate includes a circumferential concave recess. 
     
     
         3 . The intervertebral implant of  claim 2 , wherein the inner surface of the upper baseplate has a central post extending outwardly therefrom, the central post surrounded by the circumferential concave recess of the inner surface of the upper baseplate. 
     
     
         4 . The intervertebral implant of  claim 3 , wherein the central post includes a longitudinal axis and a head end. 
     
     
         5 . The intervertebral implant of  claim 4 , wherein the articulation member includes a flat surface having a bore therein, the bore adapted to house the central post of the upper baseplate. 
     
     
         6 . The intervertebral implant of  claim 1 , wherein the articulation surface of the housing is a circumferential concave surface configured to matingly engage the spherical outer surface of the articulation member. 
     
     
         7 . The intervertebral implant of  claim 2 , wherein the housing includes a top surface having a circumferential convex portion configured to at least partially enter the circumferential concave recess of the upper baseplate as the lower and upper baseplates articulate with respect to one another. 
     
     
         8 . The intervertebral implant of  claim 7 , wherein the articulation of the lower and upper baseplates with respect to one another is limited when the circumferential concave recess of the upper baseplate contacts the circumferential convex portion of the housing. 
     
     
         9 . The intervertebral implant of  claim 1 , wherein at least one of the outer vertebral body contact surfaces of the lower and upper baseplates is osteoinductive. 
     
     
         10 . The intervertebral implant of  claim 5 , wherein the head end of the post is compression lockable into the bore of the articulation member. 
     
     
         11 . The intervertebral implant of  claim 1 , wherein at least one of the outer vertebral body contact surfaces of the lower and upper baseplates is dome shaped. 
     
     
         12 . The intervertebral implant of  claim 1 , wherein the spherical portion of the inner surface of the lower baseplate is surrounded by a circumferential wall and a circumferential recess on the inner surface of the lower baseplate. 
     
     
         13 . The intervertebral implant of  claim 1 , wherein the housing further includes a bottom surface having a circumferential recess and a circumferential wall. 
     
     
         14 . The intervertebral implant of  claim 13 , wherein the bottom surface of the housing is secured to the inner surface of the lower baseplate by engaging the circumferential wall of the bottom surface of the housing with the circumferential recess of the inner surface of the lower baseplate and engaging the circumferential recess of the bottom surface of the housing with the circumferential wall of the inner surface of the lower baseplate. 
     
     
         15 . The intervertebral implant of  claim 1 , wherein the stop surface of the recess of the articulation member is concave, and wherein the protrusion of the articulation surface of the housing has a convex stop surface, and articulation of the lower and upper baseplates with respect to one another is limited when the convex stop surface of the protrusion of the articulation surface of the housing contacts the concave stop surface of the recess of the articulation member.