OBJECTIVE: To perform an experimental study of the impact of intersomatic bone graft height of the cervical spine on the mechanical stability of anterior cervical fixation. METHODS: Mechanical assays were performed using swine cervical spine (C3-C4). Three experimental groups were formed with 20 cervical spine segments (C3-C4) according to the degree of stability achieved and the fixation of the vertebral segment. Group I: removal of the intervertebral disc and placement of intersomatic graft. Group II: removal of the intervertebral disc, placement of the intersomatic graft, and anterior fixation with plate. Group III: removal of the intervertebral disc, bilateral section of posterior ligaments and joint capsules, placement of intersomatic graft, and anterior fixation with plate. Each experimental group was divided into two subgroups, according to the height of the bone graft used (3.0 mm or 6.0 mm). Vertebral segments were submitted to mechanical assays of flexion, lateral flexion, and torsion in a universal assay machine. The parameters analyzed were maximum strength (N) and the time (Nm) to produce a predetermined deflection. RESULTS: Considering all experimental groups, the authors did not observe a statistical difference among the maximum strength (N) and time (Nm) between the different heights (3.0 mm and 6.0 mm) of the intersomatic bone graft. CONCLUSIONS: Immediate mechanical stability of anterior monosegmental cervical arthrodesis was not impacted by the intersomatic graft height in the flexion, lateral flexion, and torsion assays.
Spine; Bone transplantation; Biomechanics; Spinal fusion; Cervical vertebrae; Swine
