Patent ID: 8523944

Claim:
A distractible intervertebral body fusion device for implantation into an intervertebral disc space in a patient's body, comprising: a top end plate having a top bearing surface configured to interface with an end plate of a superior vertebra of the intervertebral disc space; a bottom end plate having a bottom bearing surface configured to interface with an end plate of an inferior vertebra of the intervertebral disc space; and at least two struts connecting the top end plate and the bottom end plate, each strut comprising first and second structural members and a block, wherein each structural member is connected at one end to one of the end plates with a flexure member and at an opposed end to the block with a flexure member, and wherein the blocks include apertures enabling operable access to an expansion tool such that actuation of the expansion tool in a first direction drives the blocks closer together, causing the struts to expand, thereby distracting the top end plate and the bottom end plate with respect to each other, wherein one of the end plates provides a backstop for each flexure connecting one of the structural members with the respective end plate, the backstop providing a rolling contact with the flexure that guides a curvature of the flexure as the top and bottom end plates distract, the curvature of the flexure conforming to a shape of the backstop, and wherein the backstops are one of concave or convex.