An interbody fusion device including a body member, at least one side member engaging the body member, and at least one movement mechanism that engages at least one side member and the body member. A surgical method for maintaining a space between two vertebral bodies in a spine, including the steps of obtaining a medical device, such as an interbody fusion device, and inserting and coupling an expansion tool into an opening within the medical device. The surgical method also including slidingly inserting the medical device into a space between two vertebral bodies and rotating the expansion tool to move the at least one side member in a direction relative to the body member. The method may further include detaching the expansion tool from the medical device and removing the tool from the space between the two vertebral bodies in the spine.