Fig. 1.

Following destruction of the anterior column, restabilization occurs by one of the three methods. a In patients with partially destroyed vertebrae, restabilization occurs with a wide contact area. There is no dislocation of the facet joints. b In patients with dislocation of a single facet joint, restabilization occurs by point contact. c In patients with loss of two or three vertebrae in the thoracolumbar region, the facets dislocate at multiple levels. The superior segment of the vertebral column rotates by 90° so the anterior surface of the superior vertebra rests on the superior surface of the inferior vertebra. The superior segment of the vertebral column becomes horizontal