A biomechanical analysis of posterior cervical fusions using polymethylmethacrylate as an instantaneous fusion mass

Three posterior fusion reconstruction procedures for a canine experimental model of the C4-C5 bilateral facet dislocation are herein mechanically tested. The two procedures utilizing polymethylmethacrylate have increased angular stiffness as compared with the normal posterior soft tissue structures and the reconstruction procedure utilizing wire alone. Their ultimate moments are not significantly greater. These findings lead us to predict an increased incidence of fixation failure when polymethylmethacrylate acrylic cement preparations are used for instantaneous posterior "fusions" as compared with the more traditional wire and bone graft procedure.