Progression of Unsupported Curves in Adolescent Idiopathic Scoliosis

Stability of three types of double scoliotic curves of 10-40 degrees was analyzed using a biomechanical model: double primary (Type I), primary thoracic with compensatory lumbar (Type II), and primary lumbar with compensatory thoracic (Type III). The load-carrying capacity of each curve was analyzed as a function of magnitude of the curve, its location and flexibility. Curve magnitude was found to be the most influential parameter governing the stability of a scoliotic curve up to 30 degrees. Results suggest that in evaluating curves of comparable magnitudes, Type I and II curves are more likely to progress and, therefore, should be braced at an earlier stage than Type III curves.