The anterior cervical plate fixation systems have been widely used in treatment of complex spinal disorders such as traumatic lesion, disc hernination, tumor, spondylosis, arthritides, and others. Combined with bone graft or other fusion techniques the satisfactory outcomes were higher than 88% (Clements 1990, Naito 1993,Bose 1998, Schneeberger 1999). Among the screw plate fixation systems, Cas...