Devices and methods for correcting vertebral misalignment
Devices and methods of correcting vertebral misalignment, including, e.g., spondylolisthesis, are disclosed. In one embodiment, a vertebral implant may include an assembly configured to be secured to a first vertebral body, wherein the assembly includes a frame made of a first material and at least one end plate made of a second material different than the first material; a reducing plate configured to be slidably received over the central portion, wherein the reducing plate is configured to be secured to a second vertebral body; and an actuator configured to move the reducing plate relative to the frame.
1. A method of correcting vertebral misalignment, the method comprising:
positioning a vertebral implant within a space between two adjacent vertebral bodies, wherein the implant includes:
a reducing plate including a head portion, a first extension plate, and a second extension plate, the first and second extension plates extending posteriorly from a posterior surface of the head portion, wherein the first and second extension plates are spaced from one another to define a channel therebetween;
a frame member comprising a right lateral section, a left lateral section, and a central longitudinal member positioned in between the right and left lateral sections, the central longitudinal member defining a lumen extending therethrough, wherein the central longitudinal member comprises a first through hole extending from a superior external surface of the central longitudinal member to an inferior external surface of the central longitudinal member and in communication with the lumen; and
an actuator extending through the head portion of the reducing plate and into the lumen of the frame member, and
moving the actuator to translate the reducing plate relative to the central longitudinal member of the frame member, wherein moving the actuator causes the first extension plate to slide above the superior external surface of the central longitudinal member, the second extension plate to slide below the inferior external surface of the central longitudinal member, and the central longitudinal member to be received in the channel.
2. The method of claim 1 , wherein the actuator is a threaded actuator that is rotatable.
3. The method of claim 1 , further comprising a first endplate and a second endplate, wherein the left lateral section receives the first endplate and the right lateral section receives the second endplate.
4. The method of claim 3 , further comprising a third endplate received on the first extension plate and a fourth endplate received on the second extension plate.
5. The method of claim 1 , wherein the central longitudinal member includes a posterior portion having a slanted surface.
6. The method of claim 1 , further comprising a friction ring having an opening corresponding to the lumen, the friction ring being positioned between the frame member and the reducing plate, and the actuator extends through the opening in the friction ring.
7. The method of claim 1 , further comprising a fastener restricter configured to retain one or more screws within the implant and restrict movement of the actuator.
8. The method of claim 7 , wherein the fastener restricter includes a screw having a head including a plurality of cutouts disposed in an external wall.
9. The method of claim 1 , wherein the reducing plate includes a first material that is radiopaque and the frame member includes a second material that is radiolucent.
10. The method of claim 9 , wherein the first material is titanium and the second material is a thermoplastic polymer.
11. A method of correcting vertebral misalignment, the method comprising:
positioning a vertebral implant within a space between two adjacent vertebral bodies, wherein the implant includes:
a reducing plate comprising a head portion, a first extension plate, and a second extension plate, the first and second extension plates extending posteriorly from a posterior surface of the head portion, wherein the first and second extension plates are spaced from one another to define a channel therebetween;
a frame member comprising a right lateral section, a left lateral section, and a central longitudinal member positioned in between the right and left lateral sections, the central longitudinal member defining a lumen extending therethrough, wherein the central longitudinal member comprises a first through hole extending from a superior external surface of the central longitudinal member to an inferior external surface of the central longitudinal member and in communication with the lumen; and
an actuator extending through the head portion of the reducing plate and into the lumen of the frame member,
moving the actuator to cause movement of the reducing plate relative to the frame member, thereby correcting misalignment of the adjacent vertebral bodies.
12. The method of claim 11 , wherein the actuator is a threaded actuator that is rotatable.
13. The method of claim 11 , further comprising a first endplate and a second endplate, wherein the left lateral section receives the first endplate and the right lateral section receives the second endplate.
14. The method of claim 13 , further comprising a third endplate received on the first extension plate and a fourth endplate received on the second extension plate.
15. The method of claim 11 , wherein the central longitudinal member includes a posterior portion having a slanted surface.
16. The method of claim 11 , further comprising a friction ring having an opening corresponding to the lumen, the friction ring being positioned between the frame member and the reducing plate, and the actuator extends through the opening in the friction ring.
17. The method of claim 11 , further comprising a fastener restricting mechanism configured to retain one or more screws within the implant and restrict movement of the actuator.
18. The method of claim 17 , wherein the fastener restricting mechanism includes a screw having a head including a plurality of cutouts disposed in an external wall.
19. The method of claim 11 , wherein the reducing plate includes a first material that is radiopaque and the frame member includes a second material that is radiolucent.
20. The method of claim 19 , wherein the first material is titanium and the second material is a thermoplastic polymer.