EXPANDABLE INTERBODY FUSION DEVICE

摘要

An expandable interbody fusion device includes superior and inferior plates that are configured to receive a sequentially inserted stack of expansion members or wafers. The superior and inferior plates include features that at least initially interlock the two plates until the superior plate is dislodged by pressure from the growing wafer stack. The wafers include features on their top and bottom surfaces that interlock the wafers in multiple degrees of freedom so that the wafer stack is not disrupted when the fusion device is fully expanded. Each wafer also includes features that interlock with the inferior plate until the wafer id dislodged by sequential introduction of another wafer.

主权项

1. An expandable interbody fusion device for implantation into the intradiscal space between the opposing vertebral bodies in a spine, comprising:
an elongate upper plate having an outer surface configured to contact one vertebral body in a spine and an inner beveled surface generally opposite said outer surface; an elongate lower plate generally axially aligned with said elongate upper plate, said lower plate having an outer surface configured to contact the other opposing vertebral body and an inner surface generally opposite said outer surface and facing said inner beveled surface of said upper plate, said lower plate having opposing spaced apart sidewalls defining therebetween an interior cavity, said upper plate being movable in an expansion direction relative to said lower plate toward the one vertebral body; an elongate expansion member sized to be received between said upper plate and said lower plate into said interior cavity in contact with said inner surface of said lower plate and movable in alignment with the elongate direction of said upper plate and said lower plate in a first axial direction that is substantially perpendicular to said expansion direction, said expansion member including a beveled lifting surface operable upon movement of said expansion member to engage the inner beveled surface of said upper plate to move said upper plate away from said lower plate in the expansion direction and expand said device; and an engagement structure between said expansion member and said sidewalls of said lower plate comprising a projection and an opening.