Method and apparatus for promoting a spinal fusion between neighboring vertebrae. The apparatus may be located in an intervertebral disc space and the apparatus preferably includes a pair of engaging plates for contacting the vertebrae. An alignment device of the apparatus may be used to alter the vertical...http://www.google.es/patents/US6080193?utm_source=gb-gplus-sharePatente US6080193 - Adjustable height fusion device
