A dynamic fusion device for facilitating arthrodesis in a disc space between adjacent vertebrae that includes a body and an engaging member. The body extends along a longitudinal axis having a first portion and two or more legs depending from the first portion. The legs are laterally spaced apart from...http://www.google.com.tw/patents/US6117174?utm_source=gb-gplus-share專利 US6117174 - Spinal implant device
