Introduction: Ponseti and Friedman suggest that curve type is genetically determined and that curve types do not change throughout its course. In current clinical practice scoliosis is seen as a more dynamic process. Therefore we like to postulate that the natural history of idiopathic scoliosis can change during growth when left untreated.

Aim of the Study: This study focused on the shift of curve patterns as result of age, especially in patients younger than ten years. It was assessed whether age is a factor in the dynamic progression of idiopathic scoliosis. We evaluated patients records as well as radiographic images and clinical measures.

Materials and Methods: 48 Patients with idiopathic scoliosis who visited the scoliosis team between 1990 and 2007 were included. The criteria for inclusion were a curve less than 30° and not treated with brace or operative procedures. Curve pattern changes were classified according to the Scoliosis Research Society classification and the Lenke classification.

Results: The forty-eight patient records demographics consisted of eleven males and thirty-seven females. Their mean age at the start of follow-up was 11,2 years (range 4–17). Mean follow-up lasted 3,4 years (range 1–11,2). Thirteen patients were diagnosed with juvenile idiopathic scoliosis and thirty-five patients were diagnosed with an adolescent idiopathic scoliosis. Eight from the forty-eight patients, showed curve pattern changes according the SRS classification: six females and two males. Six of the thirtteen patients with juvenile scoliosis showed a shift of the scoliosis curves (46%). Two of the thirty-five patients with the adolescent scoliosis showed a shift of the scoliosis curves (6%; p< 0,05).

In eleven patients with juvenile scoliosis(84,6%) there was a shift in the Lenke classification, while this only occurred in eighttteen patients with adolescent scoliosis(51,4%) (p< 0,05). No curve pattern changes occurred in two patients with juvenile idiopathic scoliosis(15,4%) and in twelve patients of the adolescent idiopathic scoliosis(34,3%) (p< 0,05).

Conclusion: There is evidence that idiopathic scoliosis has an genetic origin, but not all elements of the scoliosis formation can be explained. We found changes in curve patterns which suggest that idiopathic scoliosis is not a fixed deformity, but a dynamic process especially in patients younger than 10 years.