Expandable fusion device with integrated deployable retention spikes
Expandable fusion devices, systems, and methods. The expandable fusion device includes one or more integrated deployable retention spikes configured to resist expulsion of the device when installed in the intervertebral disc space. The implant may include upper and lower main endplates, an actuator assembly configured to cause an expansion in height of the upper and lower main endplates, and a sidecar assembly including a sidecar carrier, an upper carrier endplate engaged with an upper spike, and a lower carrier endplate engaged with a lower spike such that forward translation of the sidecar carrier pushes against the upper and lower carrier endplates, thereby deploying the upper and lower spikes.
1. An expandable implant comprising:
upper and lower main endplates configured to engage adjacent vertebrae, at least one of the upper and lower main endplates defines a curved channel and a straight channel;
an actuator assembly configured to cause an expansion in height of the upper and lower main endplates; and
a sidecar assembly including a sidecar carrier and a carrier endplate with a pusher engaged with a spike having a top surface comprising a pair of grooves along a longitudinal length bifurcated by a rib extending centrally therebetween, wherein the spike is positionable through the curved channel and the pusher is receivable in the straight channel, and wherein forward translation of the sidecar carrier deploys the spike.
2. The expandable implant of claim 1 , wherein the curved and straight channels overlap such that the curved channel intersects the straight channel.
3. The expandable implant of claim 1 , wherein the straight channel is a blind channel that extends along a longitudinal axis of the implant.
4. The expandable implant of claim 1 , wherein the curved channel arcs outwardly toward an outer surface of the upper or lower main endplate.
5. The expandable implant of claim 1 , wherein in a retracted position, the spike is retained inside the curved channel, and as the sidecar carrier translates forward, the spike travels through and extends from the curved channel, and the pusher follows the straight channel.
6. The expandable implant of claim 1 , wherein the spike extends from a proximal end to a free end, and a moveable joint connects the proximal end of the spike to a distal end of the pusher.
7. The expandable implant of claim 6 , wherein the moveable joint is a pivotable joint such that the proximal end of the spike includes a convex base receivable in a corresponding pocket in the pusher, and the pocket permits the convex base to travel along a vertical axis to deploy the spike.
8. The expandable implant of claim 6 , wherein the moveable joint is a ball and socket joint.
9. An expandable implant comprising:
upper and lower main endplates configured to engage adjacent vertebrae;
an actuator assembly configured to cause an expansion in height of the upper and lower main endplates;
a sidecar assembly including a sidecar carrier and a carrier endplate with a pusher engaged with a spike having a top surface comprising a pair of grooves along a longitudinal length bifurcated by a rib extending centrally therebetween and a convex base captured in a pocket defined in a free end of the pusher, wherein forward translation of the sidecar carrier translates the carrier endplate and deploys the spike.
10. The expandable implant of claim 9 , wherein the pocket allows the convex base to travel up and down along a vertical axis and the spike is pushed forward, rotating, and translating to a deployed position.
11. The expandable implant of claim 10 , wherein the pocket allows the spike to rotate about an axis coincident with a radius of curvature of the spike.
12. The expandable implant of claim 9 , wherein the convex base is rounded but non-spherical.
13. The expandable implant of claim 9 , wherein a bottom surface of the spike defines a slot, which causes the convex base to form a downward hook.
14. The expandable implant of claim 13 , wherein the pocket is undercut such that a tip of the pusher forms an upward hook.
15. The expandable implant of claim 14 , wherein the upward hook of the pusher is receivable in the slot of the spike and the downward hook of the convex base is receivable in the pocket of the pusher.
16. The expandable implant of claim 9 , wherein the actuator assembly includes a rear ramp having a pair of parallel dovetail slots, and the sidecar carrier includes corresponding dovetails that mate with the dovetail slots of the rear ramp, allowing the sidecar carrier to translate with respect to the rear ramp along a main longitudinal axis of the implant while restricting all other translation or rotation.