Progression in untreated idiopathic scoliosis after end of growth

Seventy patients more than 16 years of age with untreated idiopathic scoliosis were followed-up for a mean period of 8.5 years. The majority of curves increased; 3 degrees per year before 20 of age and 1 degree per year after 20 years. Curves below 40 degrees increased significantly less than bigger curves and curves from 60-80 degrees increased the most. Single curves increased significantly more than double curves; thoracic curves increased significantly more than lumbar curves. It is concluded that surgery should be recommended to adolescent patients with thoracic or thoraco-lumbar single curves larger than 40 degrees, and that patients not treated operatively should be followed-up through early adult life.