Expandable footprint implant

Abstract

Expandable fusion implants capable of being installed inside an intervertebral disc space to maintain disc spacing and restore spinal stability, thereby facilitating an intervertebral fusion. The expandable intervertebral implant may be configured to transition from a collapsed configuration having a first width and a first height to an expanded configuration having a second width and a second height. The implant may include front and rear plates each having horizontal ramps configured to interface with corresponding horizontal ramps on actuators and front ramps of left and/or right side portion assemblies.

What is claimed is: 
     
         1 . An expandable intervertebral implant comprising:
 front and rear plates;   a central drive screw threadedly engaged with a drive sleeve, the central drive screw retained in the rear plate and the drive sleeve retained in the front plate;   left and right side portion assemblies each including upper and lower endplates, an actuator, and a front ramp; and   an endplate clip positioned around the drive sleeve to prevent expansion of the upper and lower endplates in height until the left and right side portion assemblies are fully expanded in width.   
     
     
         2 . The expandable intervertebral implant of  claim 1 , wherein when the drive screw is rotated, the implant expands in width and once the upper and lower endplates are released from the endplate clip, then the implant expands in height. 
     
     
         3 . The expandable intervertebral implant of  claim 1 , wherein the endplate clip includes a ring with a plurality of posts configured to engage the upper and lower endplates. 
     
     
         4 . The expandable intervertebral implant of  claim 3 , wherein the ring includes a full ring defining a central bore sized and dimensioned to snuggly fit around the drive sleeve. 
     
     
         5 . The expandable intervertebral implant of  claim 3 , wherein the posts extend from the ring and terminate at one or more free ends. 
     
     
         6 . The expandable intervertebral implant of  claim 5 , wherein before the implant is fully expanded, the free ends of the posts are received in bores through a side wall of the endplates, thereby preventing any expansion in height. 
     
     
         7 . The expandable intervertebral implant of  claim 6 , wherein once fully expanded in width, the endplates move outward and away from one another and the free ends of the posts are released from the bores, thereby allowing the upper and lower endplates to expand in height. 
     
     
         8 . The expandable intervertebral implant of  claim 3 , wherein a first post is positioned above the ring with two opposed free ends extending into the upper endplates, respectively, and a second post is positioned below the ring with two opposed free ends extending into the lower endplates, respectively. 
     
     
         9 . The expandable intervertebral implant of  claim 8 , wherein the two posts are aligned in parallel. 
     
     
         10 . An expandable intervertebral implant comprising:
 a front plate having at least one ramp and a rear plate having at least one ramp;   a central drive screw threadedly engaged with a drive sleeve, the central drive screw retained in the rear plate and the drive sleeve retained in the front plate;   a left side portion assembly and a right side portion assembly, wherein the left and right side portion assemblies each include an upper endplate, a lower endplate, an actuator, and a front ramp, wherein the actuator includes a ramp slidably engaged with the ramp of the rear plate, and the front ramp includes a ramp slidably engaged with the ramp of the rear plate; and   an endplate clip positioned between the drive sleeve and the upper and lower endplates,   wherein rotation of the drive screw moves the front plate toward the rear plate and the ramp of the actuator slides across the ramp of the rear plate, the ramp of the front ramp slides across the ramp of the front plate, thereby expanding a width of the implant, and the endplate clip prevents expansion of the upper and lower endplates in height until the left and right side portion assemblies are fully expanded in width.   
     
     
         11 . The expandable intervertebral implant of  claim 10 , wherein the drive sleeve includes a tubular body with an internally threaded bore, and the central drive screw includes an externally threaded shaft allowing for threaded engagement with the internally threaded bore of the drive sleeve. 
     
     
         12 . The expandable intervertebral implant of  claim 11 , wherein the endplate clip includes a ring fitted over the tubular body of the drive sleeve with a plurality of outwardly extending posts configured to engage the upper and lower endplates. 
     
     
         13 . The expandable intervertebral implant of  claim 12 , wherein the endplate clip includes a first post affixed to a top of the ring and a second post affixed to a bottom of the ring. 
     
     
         14 . The expandable intervertebral implant of  claim 13 , wherein the first post terminates at first and second free ends configured to engage the upper endplates and the second post terminates at third and fourth free ends configured to engage the lower endplates. 
     
     
         15 . The expandable intervertebral implant of  claim 13 , wherein the first and second posts are horizontally aligned with the upper and lower endplates, respectively. 
     
     
         16 . The expandable intervertebral implant of  claim 13 , wherein before the implant is fully expanded, the free ends of the posts are received in bores through a side wall of the endplates, thereby preventing any expansion in height. 
     
     
         17 . An expandable intervertebral implant comprising:
 front and rear plates each having horizontal ramps;   a central drive screw for moving the front plate relative to the rear plate;   an expandable assembly including an upper endplate, a lower endplate, an actuator, and a front ramp, wherein the upper and lower endplates include vertical ramps, the actuator includes horizontal ramps engaged with the horizontal ramps of the rear plate and vertical ramps engaged with the vertical ramps of the upper and lower endplates, and the front ramp having horizontal ramps engaged with the horizontal ramps of the front plate and vertical ramps interfacing with the vertical ramps of the upper and lower endplates; and   an endplate clip attached to the drive sleeve to prevent expansion of the upper and lower endplates in height until the expandable assembly is fully expanded in width.   
     
     
         18 . The expandable intervertebral implant of  claim 17 , wherein the endplate clip includes one or more posts receivable in corresponding bores in the upper and lower endplates. 
     
     
         19 . The expandable intervertebral implant of  claim 18 , wherein the endplate clip only permits lateral expansion of the expandable assembly until the posts disengage from the bores in the upper and lower endplates. 
     
     
         20 . The expandable intervertebral implant of  claim 18 , wherein a first post is receivable in the bore in the upper endplate and a second post is receivable in the bore in the lower endplate, and the first and second posts are aligned in parallel.