Patent ID: 8123755

Claim:
An interbody fusion device for the distraction and support of opposing vertebral bodies in a spine at a selected spacing between said vertebral bodies, comprising a plurality of elements in cooperative contact forming a structure between said opposing vertebral bodies generally extending in the direction of the axis of the spine, said structure being formed by the consecutive individual receipt in vivo of said elements between said opposing vertebral bodies to achieve the selected spacing between said vertebral bodies upon receipt thereof, said elements comprising complementary interfaces that upon formation of said structure substantially restrain any movement between adjacent elements in said structure in all directions, said elements being defined by a plurality of elongate stackable wafers cooperatively forming said structure as a column between said two opposing vertebral bodies, the wafers each having a contact surface, a contact surface of one wafer being slidably receivable in vivo beneath a contact surface of another wafer, each wafer being configured to cause expansion of said column in substantially only one direction upon receipt of each wafer and that upon such expansion said column provides a force to distract and support said opposing vertebral bodies.