OBJECTIVE: evaluation of the mechanical stability of the internal vertebral fixation through the influence of the anterior load bearing reconstruction and stabilization. METHODS: cylindrical woods blocks were utilized as test bodies and were stabilized by an internal fixation. Three experimental groups were set according to the anterior reconstruction and fixation: group I - without anterior support; group II - with anterior support and group III - with support and anterior fixation. In an universal assay machine the wood block underwent to flexion-compression, lateral flexion and torsion mechanical assays, until ten assays of each modality were performed (flexion-compression, lateral compression and torsion) in each experimental group, in a total of 90 mechanical assays. The studied mechanical proprieties were the flex moment, torsion moment and the stiffness, obtained through the load x deflection of each mechanical trial. RESULTS: it was observed that utilizing a support and anterior fixation there has been na increased mechanical stiffness in the flexion-compression mechanical assays. In the lateral flexion tests it was observed an increased rigidity only with the anterior fixation. CONCLUSION: with the torsion tests the anterior support and fixation did not increase the mechanical rigidity of the vertebral fixation system.
Orthopedic fixation devices; Internal fixators; Biomechanics; Spine
