Comparative strengths of various anterior cement fixations of the cervical spine

In vivo study, using cadaveric dog cervical spine, was performed in which the middle segment of the vertebral body was removed producing anterior instability. Eleven various methods of stabilization utilizing polymethylmethacrylate and other fixation devices were employed, and their static strength in hyperextension was tested and compared. A portion of the same dog's cervical spine in each case was used as a control. The results indicate that all fixation methods failed to regain the normal structural strength in extension. Cement with wire or chain methods of fixation were superior to other methods in this study. Fixation rigidity approaching rigidity of the normal spine appeared to be a significant factor determining the strength of the reconstructed cervical spine. Combined anterior and posterior fixation did not provide further strength, although it did increase the rigidity of the fixation.