received by the International Bureau on 24 April 2015 (24.04.2015)

What is claimed is:

1. An expandable interbody fusion device for implantation into an intradiscal space between two opposing vertebral bodies of a spine, comprising:

a first endplate having an outer surface configured to contact one of said vertebral bodies and an opening extending through said outer surface;

a second endplate having an outer surface configured to contact the other vertebral body and an inner support surface, said second endplate having opposing spaced apart sidewalls and opposing spaced apart front and rear endwalls defining therewithin a fully bounded interior cavity, said support surface being within said interior cavity, said first endplate being received within said interior cavity, said second endplate having at least one opening extending through said outer surface and said support surface and communicating with said interior cavity, said rear endwall defining therethrough a fully bounded channel in communication with said interior cavity, said first endplate being movable in an expansion direction relative to said second endplate toward the opposing vertebral body;

at least one insert having an upper surface, an opposite lower surface, a front end, a rear end and an open rearward facing opening extending through said upper surface, said lower surface and the rearmost surface of said rear end, said at least one insert being configured to be introduced between said first endplate and said second endplate through said channel into said interior cavity in an insertion direction that is substantially perpendicular to said expansion direction and supported by said support surface therewithin with the front end of said insert adjacent the front endwall of said second endplate and the rear end of said insert adjacent the rear endwall of said second endplate, said rearward facing opening

communicating with said channel and being in at least partial alignment with said openings through said first endplate and said second endplate; and

locking surfaces on said at least one insert to lock said at least one insert in said device.

2. The device of claim 1, wherein said at least one insert includes a pushing surface between said upper and lower surface within and communicating with said open rearward facing opening.

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3. The device of claim 2, wherein a locking surface of said locking surfaces on said at least one insert is disposed on one of said upper surface and said lower surface adjacent the front end of said insert, and wherein said open rearward facing opening defines a U-shaped opening, the base of said opening defining said pushing surface.

4. The device of claim 3, wherein said locking surface includes at least one resiliently interlocking element.

5. The device of claim 4, wherein said locking surfaces further include a T-bar configuration on one of said upper surface and said lower surface and a T-bar configuration on the other of said upper surface and said lower surface.

6. The device of claim 5, including at least two of said inserts at least one insert of substantially identical configuration.

7. The device of claim 1, wherein the material of said second endplate is substantially radiopaque and said second endplate has at least one window therethrough for observation of one of said first endplate and said at least one insert during expansion of said device.

8. The device of claim 1, further including a threaded opening through the rear endwall of said second endplate, said threaded opening being spaced from said channel and configured for threaded receipt of a guide pin of an inserter for inserting said device into the intradiscal space between said two opposing vertebral bodies.

9. An apparatus for use in spinal interbody fusion, comprising:

an expandable device including a first outer surface for contacting one vertebral body in a spine and a second outer surface for contacting a second opposing vertebral body in said spine, a front end and a rear end, said device comprising a first opening through said first outer surface and a second opening through said second outer surface and a channel through said rear end, said guide pin being releasably connected to said device at a location spaced from said channel; and

18 an inserter releasably attached to said device at said rear end and including a track for inserting an insert into said expandable device, said inserter comprising a guide pin releasably connected to said device and detachably connected to said inserter, said inserter supporting a plurality of inserts for sequential insertion into said channel, one beneath the other, each of said inserts having a rearward facing opening and a pushing surface engaged by a driver of said inserter to insert said inserts into said device.

10. The apparatus of claim 9, wherein said device comprises at least one window therethrough for observation of said inserts during expansion of said device.

1 1. The apparatus of claim 10, wherein each of said inserts is formed of a biocompatible polymer.

12. The apparatus of claim 9, wherein said guide pin is releasably connected with said device upon detachment of said inserter from said device and said guide pin, said guide pin serving as a locator for subsequent attachment to another apparatus, including an apparatus for introducing graft material into said device through said channel.

13. The apparatus of claim 9, wherein said expandable device comprises a first endplate defining said first outer surface and said first opening therethrough, and a second endplate defining said second outer surface and said second opening therethrough, said first endplate and said second endplate being movable relative to each other in an expansion direction.

14. The apparatus of claim 13, wherein said second endplate includes said channel at a rear end thereof, said rear end of said second endplate including an attachment surface for releasable attachment of said inserter.

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15. The apparatus of claim 14, wherein said attachment surface includes at least one notch adjacent the rear end of said second endplate.

16. The apparatus of claim 15, wherein said inserter includes a distal end comprising at least one finger releasably engaged in said at least one notch.

17. The apparatus of claim 13, wherein said guide pin is elongate having a distal end and a proximal end, the distal end having a threaded extent, and wherein said attachment surface includes a threaded opening in receipt of said threaded extent of said guide pin.

18. The apparatus of claim 17, wherein said inserter includes a track assembly having a distal end and a proximal end, said track assembly supporting said guide pin and being detachable therefrom.

19. The apparatus of claim 18, wherein said inserter includes a rotatable quick disconnect member at the proximal end of said track assembly for allowing said track assembly to be detached from said guide pin while said guide pin remains releasably connected to said rear end of said second endplate.

20. The apparatus of claim 13, wherein one of said first endplate and said second endplate is formed of titanium.

21. The apparatus of claim 18, wherein said track assembly further comprises an elongate driver translatably movable thereon, said driver having a distal end and a proximal end, the distal end being configured to engage the pushing surface on each said insert and drive said insert into said expandable device through said channel.

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22. The apparatus of claim 21, wherein said insert comprises an elongate body having a front end, a rear end, and a rearward facing opening defining a U-shaped opening, a base of said opening defining a pushing surface.

23. The apparatus of claim 22, wherein said driver is sized and configured to enter said U-shaped opening of said insert and engage said pushing surface of said insert.

24. The apparatus of claim 23, wherein said inserter includes an actuator attached to said track assembly and operable to translatably move said driver along said track assembly.

25. An apparatus for use in spinal interbody fusion, comprising:

an expandable device including a first outer surface for contacting one vertebral body in a spine and a second outer surface for contacting a second opposing vertebral body in said spine, a front end and a rear end, a channel through said rear end and an attachment surface on said rear end at a location spaced from said channel, said device comprising a first opening through said first outer surface and a second opening through said second outer surface and a plurality of inserts sequentially inserted into said device, one beneath the other, between said first outer surface and said second outer surface, each of said inserts having a rearwardly facing U-shaped opening in communication with each other and with the openings through said first and second outer surfaces; and

a guide pin releasably attached to said expandable device at said attachment surface thereof.

26. The apparatus of claim 25, further comprising bone graft material received into said expandable device through said channel while said guide pin is releasably attached to said the expandable device.

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27. The apparatus of claim 26, wherein said guide pin is releasably connected to said device at a location spaced from said channel, said bone graft being disposed in said U- shaped openings of said inserts within said expandable device and into said first opening and said second opening.

28. The apparatus of claim 25, wherein said guide pin is elongate, one end of which comprises a threaded extent, said attachment surface on said rear end of said expandable device being defined by a threaded opening in receipt of said threaded extent of said guide pin.

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