Spinal Trauma and Fractures

Figure 8.
Three-column concept of the spine.

The anterior column consists of the anterior longitudinal ligament and the anterior one half of the body, disc, and annulus. The middle column consists of the posterior one half of the body, disc, and annulus, and the posterior longitudinal ligament. The posterior column consists of the facet joints, ligamentum flavum, the posterior elements, and the interconnecting ligaments. In the thoracic spine, a fourth column has been proposed, which consists of the sternum-rib complex. (48)

Compression fractures involve wedging of the anterior portion of the vertebral body, most often as a result of vertical force (Figure 9). The middle column remains intact.

Figure 9.
Lateral radiograph of a patient with a Compression Fracture.

Burst fractures are comminuted fractures of the vertebral bodies often associated with bone fragments in the canal (Figure 10). Burst fractures involve the anterior and middle columns. Usually the result of vertical loading and high energy impact, they are also frequently associated with neurologic deficit.

Figure 10.
Axial CT of a patient with a Thoracic Burst Fracture.

Fracture-dislocation injuries of the spine include any combination of fractures with dislocation. These types of spinal fractures involve all three columns, and are usually the result of compression, tension, shear, or rotation. Variants of fracture-dislocation injuries include:

(a) Anterior/posterior dislocation of the vertebral body with fracture of bony parts,

(b) Comminuted fractures of the vertebral body with anterior/posterior displacement and rotation (with tearing of ligaments), and

(c) Lateral dislocation of vertebrae with fracture. All have potentially devastating neurologic consequences.

Flexion-distraction fractures are usually the result of forceful forward flexion of the spine, which may occur in motor vehicle crashes where the victim is restrained by a lap belt only. The tensional forces can disrupt the middle and posterior columns. A variant of flexion-distraction injury is the Chance fracture, resulting from hyperflexion of the spine. All three columns fail under tensile forces in a Chance fracture. The fracture extends through the vertebral body, pedicle, lamina, and spinous process (Figure 11). The posterior ligaments are disrupted, and the intervertebral disc and facet joints may also be distracted. (49)

Figure 11.
Sagittal CT reconstruction of a patient with a thoracic Chance Fracture. Note the split pedicle.