US Patent 8118870 Expandable articulating intervertebral implant with spacer

An expandable articulating intervertebral implant is described for insertion between vertebrae of a human spine. The expandable intervertebral implant includes an upper body that engages a first vertebra of the human spine, a lower body that engages a second vertebra of the human spine, and an insert. The upper body may include an upper portion and a lower portion. The insert may be positioned between an inferior surface of the lower portion of the upper body and a superior surface of the lower body. The insert may be translated or rotated to increase a separation distance between the lower body and the upper body. A spacer may be inserted between the upper body and the lower body to maintain at least a portion of the increased separation distance between the upper body and the lower body after expansion of the intervertebral implant in the human spine.