Expandable interbody device

1. A method of implanting an expandable interbody device between adjacent vertebrae comprising:

positioning the expandable interbody device between adjacent vertebrae, wherein the expandable interbody device comprises:

an upper structure;

a lower structure configured to slideably couple with the upper structure;

a screw mechanism between the upper structure and the lower structure, wherein the screw mechanism comprises a proximal section and a distal section, the distal section comprising a keyed shaft configured to slideably engage with a matching keyed bore on the proximal section such that the screw mechanism rotates as a unit; and

a coupler, wherein the coupler comprises a proximal side configured to engage the proximal section and a distal side configured to engage the distal section;

rotating the screw mechanism to change a length of the screw mechanism from a first length to a second length which causes a distance between the upper structure and the lower structure to change from a first distance to a second distance to form a chamber; and

injecting material into the chamber.

2. The method of claim 1 , wherein the first distance corresponds to a collapsed configuration with the upper structure adjacent the lower structure and the second distance corresponds to an expanded configuration with the upper structure separated from the lower structure.

3. The method of claim 1 , wherein the proximal section comprises a proximal frustoconical surface and the distal section comprises a distal frustoconical surface.

4. The method of claim 1 , wherein the material is one or more of fluids, medication, bone graft material, allograft and demineralized bone matrix.

5. The method of claim 1 , wherein the expandable interbody device is positioned between the adjacent vertebrae using a deployment tool that extends from the vertebrae to outside an incision.

6. The method of claim 5 , wherein injecting the material comprises delivering the material through a channel extending through the deployment tool.

7. The method of claim 6 , wherein the interbody device comprises at least one recess configured to couple with the deployment tool, the at least one recess comprising a hole in fluid communication with the chamber for delivery of material from the channel of the deployment tool.

8. The method of claim 1 , wherein the coupler is prevented from rotating by at least one anti-rotational feature when the screw mechanism is rotated.

9. A method of implanting an expandable interbody device between adjacent vertebrae comprising:

positioning the expandable interbody device between adjacent vertebrae using a deployment tool that extends from the vertebrae to outside an incision, wherein the expandable interbody device comprises:

an upper structure;

a lower structure configured to slideably couple with the upper structure;

a screw mechanism between the upper structure and the lower structure, wherein the screw mechanism comprises a proximal section and a distal section, wherein the proximal section comprises at least one hole in fluid communication with the chamber for delivery of material from the channel of the deployment tool; and

a coupler, wherein the coupler comprises a proximal side configured to engage the proximal section and a distal side configured to engage the distal section;

rotating the screw mechanism to change a length of the screw mechanism from a first length to a second length which causes a distance between the upper structure and the lower structure to change from a first distance to a second distance to form a chamber; and

injecting material into the chamber by delivering the material through a channel extending through the deployment tool.

10. The method of claim 9 , wherein the first distance corresponds to a collapsed configuration with the upper structure adjacent the lower structure and the second distance corresponds to an expanded configuration with the upper structure separated from the lower structure.

11. The method of claim 9 , wherein the proximal section comprises a proximal frustoconical surface and the distal section comprises a distal frustoconical surface.

12. The method of claim 9 , wherein the material is one or more of fluids, medication, bone graft material, allograft and demineralized bone matrix.

13. The method of claim 9 , wherein the coupler is prevented from rotating by at least one anti-rotational feature when the screw mechanism is rotated.

14. A method of implanting an expandable interbody device between adjacent vertebrae comprising:

positioning the expandable interbody device between adjacent vertebrae, wherein the expandable interbody device comprises:

an upper structure;

a lower structure configured to slideably couple with the upper structure;

a screw mechanism between the upper structure and the lower structure, wherein the screw mechanism comprises a proximal section and a distal section, wherein the proximal section comprises first threads wound in a first direction configured to engage a proximal threaded hole in the coupler, and the distal section comprises second threads wound in a second direction, opposite the first direction, configured to engage a distal threaded hole in the coupler; and

a coupler, wherein the coupler comprises a proximal side configured to engage the proximal section and a distal side configured to engage the distal section;

rotating the screw mechanism to change a length of the screw mechanism from a first length to a second length which causes a distance between the upper structure and the lower structure to change from a first distance to a second distance to form a chamber; and

injecting material into the chamber.

15. The method of claim 14 , wherein the first threads and the second threads have an equal pitch, such that when the screw mechanism is actuated, a proximal end of the interbody device changes height at a same rate as a distal end of the interbody device.

16. The method of claim 14 , wherein the first threads and the second threads have a different pitch, such that when the screw mechanism is actuated, a proximal end of the interbody device changes height at a different rate than a distal end of the interbody device.

17. The method of claim 14 , wherein the first distance corresponds to a collapsed configuration with the upper structure adjacent the lower structure and the second distance corresponds to an expanded configuration with the upper structure separated from the lower structure.

18. The method of claim 14 , wherein the proximal section comprises a proximal frustoconical surface and the distal section comprises a distal frustoconical surface.

19. The method of claim 14 , wherein the material is one or more of fluids, medication, bone graft material, allograft and demineralized bone matrix.

20. The method of claim 14 , wherein the coupler is prevented from rotating by at least one anti-rotational feature when the screw mechanism is rotated.