A minimaly invasive spacer for positioning between vertebral members. The spacer is adjustable between a first orientation having a reduced size to facilitate insertion between the vertebral members. A second orientation has an enlarged size for contacting the vertebral members. The spacer includes linkages that are attached to a pair of plates. A pull arm is operatively connected to the linkages for adjusting the spacer from the first orientation to the second orientation. A delivery device is attached to the spacer for insertion between the vertebral members. In one embodiment, the delivery device is detachable to be removed from the spacer once positioned between the vertebral members. Methods of using the spacer include positioning the spacer between the vertebral members while in the first orientation. The spacer is then enlarged to the second orientation, and the delivery device is removed with only the spacer remaining within the patient.