Vertebral deformities and scoliosis.

Scoliosis, especially idiopathic scoliosis, is a complex three-dimensional deformity of the spine in which the vertebral deformities are known, cuneal deformation being the most commonly known deformity but not the only one. We report here data concerning these specific vertebral deformities in chickens. A pinealectomy was performed in a controlled series of animal experiments. This technique induces progressive scoliosis in more than 80% of chickens, with the advantage of being non-aggressive to the spine. Vertebrae included in major thoracolumbar curves were observed in 17 chickens (11 male, 6 female) and classified into three types of vertebral deformities. Vertebral deformity type 1 is characterized by three-dimensional corporeal torsion, which defines the horizontal disorientation of the curve. Vertebral deformities type 2 and 3 define lateral imbalance in the election plane of the curve. Radiological and anatomical data collected throughout the progression of the scoliosis indicate that there is a correlation between structural vertebral deformities and growth/maturation patterns. We compare our results with those reported in literature concerning human idiopathic scoliosis and experimental animal scoliosis.