Method of expanding a spinal interbody fusion device

1. A method of providing interbody fusion between two opposing vertebral bodies of the spine, comprising the steps of:

positioning an expandable spinal interbody fusion device by an inserter into a patient adjacent the spine during surgery, said inserter having a distal end releasably attached to said device and a proximal end including an actuator, said device including an inferior endplate having an outer surface configured to contact a vertebral body of the spine, a superior endplate having an outer surface configured to contact an opposing vertebral body of said spine, said inferior endplate and said superior endplate being movable relative to each other in a direction of expansion, and an elevator disposed between said inferior endplate and said superior endplate, said elevator being separate from said inserter and captively retained in said device prior to expansion for movement only along the direction of expansion independently of said movement of said inferior endplate and said superior endplate;

moving said inserter to introduce said device in an unexpanded condition into an intradiscal space between said vertebral body and said opposing vertebral body; and

operating said actuator to cause said elevator to move toward said superior endplate and move said superior endplate away from said inferior endplate to expand said device.

2. The method of claim 1 , further including the steps of:

operating said actuator to allow said elevator to move toward said inferior endplate and away from said superior endplate to create a space between said superior endplate and said elevator; and

inserting an insert movably supported by said inserter into said space.

3. The method of claim 2 , further including the step of:

operating said actuator to cause said elevator to move toward said insert and jointly move said insert and said superior endplate away from said inferior endplate to further expand said device.

4. The method of claim 3 , further including the steps of:

operating said actuator to allow said elevator to move toward said inferior endplate and away from said insert to create a space between said insert and said elevator; and

inserting a further insert movably supported by said inserter into said space between said insert and said elevator.

5. The method of claim 1 , wherein said device has a graft chamber extending therethrough for the receipt of bone fusion material, and further including the step of providing a barrier between at least a portion of said graft chamber and said elevator.

6. The method of claim 5 , wherein bone fusion material is introduced into said at least a portion of said graft chamber prior to introducing said device into said intradiscal space.

7. The method of claim 6 , wherein said device is expanded in situ and said bone fusion material in said at least a portion of said graft chamber is substantially undisturbed during expansion by said barrier.

8. A method of providing interbody fusion between two opposing vertebral bodies of the spine with an expandable spinal interbody fusion device, said device comprising expansion structure for expanding said device and having a graft chamber extending therethrough for the receipt of bone fusion material, said device including a barrier between at least a portion of said graft chamber and said expansion structure, comprising the steps of:

introducing bone fusion material into said at least a portion of said graft chamber prior to introducing said device into an intradiscal space between said two opposing vertebral bodies;

inserting said device into said intradiscal space; and

expanding said device in said intradiscal space and by said barrier substantially preventing bone fusion material from interfering with said expansion structure.

9. The method of claim 8 , wherein said expandable spinal interbody fusion device comprises an inferior endplate having an outer surface configured to contact a vertebral body of the spine, a superior endplate having an outer surface configured to contact an opposing vertebral body of said spine, said inferior endplate and said superior endplate being movable relative to each other in a direction of expansion, and an elevator disposed between said inferior endplate and said superior endplate, said elevator being captively supported for movement along the direction of expansion independently of said movement of inferior endplate and said superior endplate; and wherein said expansion is effected by moving said elevator in the direction of expansion.

10. The method of claim 9 , wherein said movement of said elevator is effected by an inserter releasably attached to said device.

11. The method of claim 5 , wherein said barrier is a graft shield attached to and extending from said inserter.

12. A method of providing interbody fusion between two opposing vertebral bodies of the spine with an expandable spinal interbody fusion device, comprising the steps of:

introducing an expandable spinal interbody fusion device by an inserter into the intradiscal space between two opposing vertebral bodies of a patient, said inserter having a distal end releasably attached to said device and a proximal end including an actuator, said device including an inferior endplate having an outer surface configured to contact one vertebral body of the spine, a superior endplate having an outer surface configured to contact an opposing vertebral body of said spine, said inferior endplate and said superior endplate being movable relative to each other in a direction of expansion, and an elevator disposed between said inferior endplate and said superior endplate, said elevator being separate from said inserter and captively retained in said device prior to expansion for movement only along the direction of expansion independently of said movement of said inferior endplate and said superior endplate;

expanding said device by said inserter, said inserter being operable to move said elevator in the direction of expansion toward said superior endplate to thereby move said superior endplate apart from said inferior endplate in the direction of expansion;

allowing a space to be created between said elevator and said superior endplate after expansion; and

inserting an insert into said space by said inserter.

13. The method of claim 12 , wherein said movement of said elevator is effected by interaction of a movable portion of said inserter with said elevator.

14. The method of claim 13 , wherein said space is created by interaction of said insert with said elevator upon insertion thereof to move said elevator after expansion of said device toward said inferior endplate.

15. The method of claim 12 , wherein said actuator comprises a trigger actuator including operable hand grips, and wherein the expansion of said device and the insertion of said insert into said expanded device are effected by operation of said hand grips of said trigger actuator.

16. The method of claim 15 , further including the step of determining whether said expanded device is capable of receiving a further insert prior to insertion of said further insert between said inferior endplate and said superior endplate.

17. The method of claim 16 , wherein said determining step is effected by tactile feedback through said actuator.

18. The method of claim 17 , wherein said determining step is effected by failure to complete a first full stroke of said hand grips of said actuator.

19. The method of claim 16 , wherein said determining step is effected by visual observation of an indicator movably coupled to said actuator to provide a visual indication of full expansion of said device.

20. The method of claim 16 , wherein the step of expanding said device is effected by a first complete stroke of hand grips of said actuator.

21. The method of claim 20 , wherein the step of inserting said insert into said expanded device into said space is effected by a second complete stroke of hand grips of said actuator.

22. The method of claim 20 , wherein the step of inserting said insert into said expanded device into said space is effected by a second stroke and a third stroke of said hand grips of said actuator.

23. A method of providing interbody fusion between two opposing vertebral bodies of the spine with an expandable spinal interbody fusion device, comprising the steps of:

introducing an expandable spinal interbody fusion device by an inserter into the intradiscal space between two opposing vertebral bodies of a patient, said inserter having a distal end releasably attached to said device and a proximal end including an actuator, said device including an inferior endplate having an outer surface configured to contact one vertebral body of the spine, a superior endplate having an outer surface configured to contact an opposing vertebral body of said spine, said inferior endplate and said superior endplate being movable relative to each other in a direction of expansion, and an elevator disposed between said inferior endplate and said superior endplate, said elevator being separate from said inserter and captively retained in said device prior to expansion for movement only along the direction of expansion independently of said movement of said inferior endplate and said superior endplate;

moving said elevator in the direction of expansion to contact said superior endplate and move said superior away from said inferior endplate and expand said device;

while said elevator is in contact with said superior endplate, at least partially inserting an insert between said superior endplate and said inferior endplate;

allowing said elevator to move toward said inferior endplate and away from said superior endplate to create a space between said superior endplate and said elevator; and

fully inserting said insert into said space between said superior endplate and said elevator.

24. The method of claim 23 , wherein said movement of said elevator in the direction of expansion to contact said superior endplate is effected by interaction of a movable portion of said inserter with said elevator.

25. The method of claim 24 , wherein said actuator is operated to cause said elevator to move toward said inferior endplate and away from said superior endplate to create said space between said superior endplate and said elevator.

26. The method of claim 25 , wherein said space is created by interaction of said insert with said elevator upon insertion thereof to move said elevator toward said inferior endplate after expansion of said device.

27. The method of claim 25 , wherein said space is created by biasing said elevator with a biasing element toward said inferior endplate after expansion of said device.

28. The method of claim 25 , wherein said elevator is moved and said insert is inserted in separate strokes of said actuator.

29. The method of claim 28 , wherein said elevator is moved exclusively during one stroke of said actuator to expand said device prior to insertion of said insert in a further stroke of said actuator.