EXPANDABLE INTERBODY FUSION DEVICE

摘要

An expandable interbody fusion device includes superior and inferior endplates that are configured to receive a sequentially inserted stack of interlocking expansion members or wafers. The like-configured 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. One of the interlocking features includes a plurality of prongs projecting from an upper surface of the wafers and into a recess defined in the lower surface of an adjacent previously inserted like-configured wafer. The prongs and recesses are configured to prevent retrograde movement of each new wafer in a direction opposite the direction of insertion. Other interlocking features prevent movement in the direction of insertion, transverse to the insertion direction and vertically within the stack.

主权项

1. An expandable interbody fusion device for implantation into the intradiscal space between two opposing vertebral bodies of a spine, comprising:
a first endplate member having an outer surface for contacting one vertebral body in a spine, said first endplate member comprising opposed spaced sidewalls and opposed spaced front and rear endwalls defining therewithin an interior cavity, an upper support surface within said cavity, and a channel opening through said rear endwall in communication with said interior cavity; a second endplate member having an outer surface for contacting an opposing vertebral body in said spine, said second endplate member being movable in an expansion direction relative to said first endplate member toward the opposing vertebral body; and at least one insert configured to be slidingly received into said device through said channel in an insertion direction that is substantially perpendicular to said expansion direction and supported by said upper support surface of said first endplate member within said interior cavity between said first endplate member and said second endplate member, said insert having an upper surface, a lower surface and a cavity formed through said upper surface and said lower surface, said insert including at least one locking surface extending into said cavity, said at least one locking surface being configured to engage cooperative structure within said fusion device during introduction of said insert into said fusion device to substantially prevent retrograde movement of said insert in a direction opposite said insertion direction.