The classification of spinal deformities.

Any methods of classification of scoliosis deformity devised should recognise different aetiological and pathological causes of the conditions and their likely impact on the natural history of the spinal curvature. Such classification should aim to aid clinicians in their approach to treatment. Furthermore, any such system must have a high reliability and validity. Several approaches have been reported. Pathological classifications have been devised which relate to the system or tissue affected by the underlying pathology, such as congenital anomalies which affect the skeletal elements of the spine, general neurological problems or muscular disorders. Classification by age of onset has also been adopted, using criteria such as infancy or adolescence. However, most attention has been focussed on structural features of the spine in developing anatomical classifications. Features such as the apex or magnitude of a curvature or its rotation are important clinical signs and are widely used in surgical practice. This paper reviews the different classification reported but make no attempt to justify one as being ideal. However, since the biological processes contributing to the deformity and its subsequent natural history are still unclear, it remains difficult to develop a fully reliable and all embracing system of classification.