Patent ID: 8795366

Claim:
An expandable intervertebral implant, comprising: a superior member configured to engage a superior intervertebral body; an inferior member configured to engage an inferior intervertebral body; and an expansion mechanism disposed between the superior member and the inferior member configured to selectively adjust a vertical separation of the superior member and the inferior member, wherein the expansion mechanism comprises a wedge structure that is translated between the superior member and the inferior member; wherein the superior member is coupled to the inferior member through the wedge structure via a track and rail system, wherein the superior member and the inferior member each comprise a pair of rails, wherein the rails of the superior member are horizontally offset relative to the rails of the inferior member such that each rail of the superior member is disposed substantially side-by-side horizontally adjacent to a respective one of the rails of the inferior member when the expandable vertebral implant is in an unexpanded configuration, and wherein one rail of the superior member is disposed between an associated rail of the inferior member and a central axis of the implant and another rail of the inferior member is disposed between the associated rail of the superior member and the central axis of the implant in the unexpanded configuration.