Articulating intervertebral implant

摘要

An intervertebral disc implant for use in the spine includes a superior endplate and an inferior endplate. The superior endplate is configured to articulate about the inferior endplate in an anterior-posterior direction during flexion and extension. The superior endplate is further configured to axially rotate about the inferior endplate during axial rotation, and is further configured to articulate about the inferior endplate along a medial-lateral direction during lateral bending. During axial rotation, the superior endplate is induced to articulate about the inferior endplate along the medial-lateral direction. During lateral bending, the superior endplate is induced to axially rotate about the inferior endplate.

主权项

1. An intervertebral implant configured to be inserted along a direction of insertion into an intervertebral space disposed between first and second vertebrae, the intervertebral implant comprising:
a first endplate having a front end and a rear end spaced from the front end along the direction of insertion into the intervertebral space, the first endplate including a first endplate body, a first articulation member that is supported by the first endplate body at a location proximate to the front end, and at least one second articulation member that is supported by the first endplate body at a location proximate to the rear end, wherein the second articulation member defines a first contact location and a second contact location, the second contact location being spaced to the right of the first contact location from a view of the first end plate in a direction from the rear end to the front end; and a second endplate having a front end and a rear end spaced from the front end along the direction of insertion into the intervertebral space, the second endplate including a second endplate body, a third articulation member supported by the second endplate body at a location proximate to the front end of the second endplate, and a fourth articulation member supported by the second endplate body at a location proximate to the rear end of the second endplate, wherein the first articulation member defines a point contact location that rides on and along an articulation surface defined by the third articulation member, and the first and second contact locations ride on and along the fourth articulation member, such that an axial rotative force applied to the first endplate in a clockwise direction, from a view of the first endplate in a direction from the first endplate toward the second endplate, causes 1) the first contact location to ride on and along the fourth articulation member in a direction away from the second endplate, and 2) the second contact location to ride on and along the fourth articulation member in a transverse direction toward the second endplate , and wherein the first endplate is disposed upward of the second endplate along the transverse direction, and the articulation surface 1) extends upward as it extends toward the rear end of the second endplate, and 2) is substantially planar as it extends toward the rear end of the second endplate.