Expandable fusion device for positioning between adjacent vertebral bodies

A method for maintaining the spacing between two adjacent vertebral bodies, comprising:

• removing at least a portion of a disc between two vertebrae of the human spine to create a disc space between the two vertebrae;
• positioning an unexpanded intervertebral implant in the disc space between the two vertebrae, wherein the intervertebral implant comprises:
• an upper body comprising an inferior surface and a superior surface;
• a lower body comprising a superior surface and an inferior surface;
• a first expansion member comprising at least a first angled portion positionable, during use, between the inferior surface of the upper body and the superior surface of the lower body, wherein at least the first angled portion is oriented towards a first end of the intervertebral implant;
• a second expansion member comprising at least a second angled portion positionable, during use, between the inferior surface of the upper body and the superior surface of the lower body, wherein at least the second angled portion is oriented towards a second end of the intervertebral implant, wherein at least the second angled portion is oriented in an opposing direction relative to at least the first angled portion;
• and
• an expansion mechanism;
• moving the first and second expansion members in opposing directions away from each other using the expansion member;
• and
• increasing a separation distance between the upper body and the lower body.