Expandable interbody fusion device with graft chambers

In an expandable interbody fusion device for implantation into the intradiscal space between two opposing vertebral bodies of a spine of the type comprising a first endplate having an outer surface defining a first perimeter configured to contact one of said vertebral bodies, a second endplate having an outer surface defining a second perimeter configured to contact the other of said vertebral bodies, and an expandable structure therebetween to separate said first endplate and said second endplate and effect expansion of said device, the improvement wherein:

• said first endplate has a multi-contoured opening extending therethough and fully disposed within a respective said first perimeter, said multi-contoured opening having a single opening through the outer surface of said first endplate and at least two openings through a lower surface of said first endplate and communicating with said single opening, said two openings at the lower surface of said first endplate being spaced by a cross member extending transversely across the first endplate at the lower surface thereof, said cross member defining at the lower surface thereof a shaped configuration with mating features for interlocking engagement with said expandable structure.