Patent ID: 8894712

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 from the inferior member; wherein the expansion mechanism comprises a proximal wedge structure and a distal wedge structure that are relatively translated between the superior member and the inferior member, wherein the proximal wedge structure and the distal wedge structure are each coupled to the superior member and the inferior member by track structures and rail structures; wherein a load-bearing portion of a bottom surface of the superior member is configured to mate vertically with a load-bearing portion of a top surface of the inferior member when the expansion mechanism is undeployed via conformal protruding and recessed features; and wherein the superior member and the inferior member each comprise a pair of rails, wherein the rails of the superior member are horizontally offset in the same direction from 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.