Production of a reproducible spinal burst fracture for use in biomechanical testing.

We have developed a technique to create a reproducible spinal burst fracture of the 12th vertebral body using 6-8-week-old calf spines with ribs, muscles, and vessels resected. We used the entire thoracolumbar segment of 20 calf spines with a standardized 5-mm-deep slice placed onto the body of T12 and the T11-12 disc. We then delivered a proximal-axial impact to the vertically mounted spine, preflexed to 15 degrees of forward flexion, by dropping a 32-kg weight, guided by a 1.55-m steel rod (potential energy = 487 J). Motion was limited to anterior flexion only, at the T12-13 disc, by splinting the rest of the spinal segments. Fractures were documented with the use of radiographs and computed tomography (CT) scans. We noted disruption of the vertebral column and end plates, fracture of the posterior body wall, fracture of the pedicles, and retropulsion of bony fragments into the neural canal. With the production of a reproducible spinal burst fracture model, various spinal fixation devices can be applied and tested.