[Criteria for treatment of idiopathic scoliosis between 40 degrees and 50 degrees. Surgical vs. conservative therapy].

The treatment of idiopathic scoliosis over 40 degrees (Cobb) during the growth period is under discussion concerning the indication for conservative or surgical treatment. Curve progression depends on the degree of the frontal and sagittal deformity, vertebral rotation, rigidity of the curve, the skeletal age, the age and sex of the patient, the familial frequency of scoliosis and the location of the curve. In scoliosis over 40 degrees progression is fast and the possibilities for successful conservative brace treatment are reduced during the growth period. Progression occurs more frequently in thoracic and double major scolioses, especially in young patients (Risser sign 0 and 1). Predictive factors of a successful brace treatment are the correction of scoliosis and rotation; deterioration of both during the brace treatment leads to poor results. Evaluating the flexibility of the sagittal profile is important, as is primary correction of 30-50% in the brace during the 3 months. Operative correction of small primary curves reduces the fusion length, operation time, and blood loss and is followed by a reduction in loading on the adjacent vertebral segments in comparison to the long fusions necessary in more structural and double major scolioses. So far it is not possible to make an equivalent judgment of the frequency of the "crankshaft" phenomenon and the treatment necessary in young patients (Rissersign 0 and 1) treated by dorsal instrumentation alone, but temporary brace treatment may be considered in those cases.