An expandable fusion device capable of being inserted between adjacent vertebrae and expanded laterally to facilitate the fusion process and the use of such device. The expandable fusion device can expand laterally such that it expands the cross-sectional support area of the device to provide more stable support of the support the spine and maintain the normal spacing between opposing vertebrae. The interior area of the expandable fusion device (in which the bone graft can be packed) does not decrease (and generally increases) during expansion of the device. This facilitates pre-packing of the expandable fusion device before utilization.
