Anterior spinal fixators. A biomechanical in vitro study.

In vitro calf spine testing was performed in flexion, rotation, and axial load, using a vertebral body corpectomy and anterior iliac crest bone grafting model. Anterior spinal fixation devices then were sequentially tested, and axial stiffness, torsional stiffness, and flexural strain determined. The constructs tested were the Contoured Anterior Spinal Plate (CASP), the Kaneda device, the Kostuik-Harrington device (KH), and the Texas Scottish Rite Hospital (TSRH) vertebral body screw construct. In torsion, the Kaneda device returned spinal stability to that of the intact spine. The Kostuik-Harrington device was unstable in torsion. In axial loading and flexion, the Kaneda device and the TSRH construct proved the most stiff, with the KH and CASP systems significantly lower in stiffness. The authors believe that the Kaneda device and the TSRH vertebral body screw construct are effective in restoring acute stability to the lumbar spine after corpectomy.