The conventional classification of idiopathic scoliosis is based on a radiological evaluation in the P/A view and different types are identified according to the position of the apex without any consideration of the sagittal view. This classification provides only partial information even though scoliosis is known as a three-dimensional deformation of the spine associated with postural disorganization.  When comparing x-rays among patients classified as the same, several differences in the morphological aspect of the curvature and other characteristics may be noted.  Clinically, the differences in posture for these patients are obvious enough to reconsider if they are indeed of the same type of scoliosis.  This has lead to the development of subclasses of the conventional classification of scoliosis patients.  A classification that reflects the three-dimensional deformation of the spine and the associated postural disorganization is therefore essential.

Observation of specific parameters, by combining frontal and sagittal x-rays, in order to get the maximum 3D information is involved.