Changes in curve pattern after brace treatment for idiopathic scoliosis.

We studied whether thoracic Boston brace treatment changes the King type of scoliotic curves in a group of 50 patients with adolescent idiopathic scoliosis. Bending radiographs showed more flexibility of the lumbar curves than that of the thoracic curves. However, after initial application of the brace, the mean lumbar correction in degrees was less than the mean thoracic correction. After brace treatment we found a slight statistically significant increase in the mean lumbar curve, but no significant change in the mean thoracic curve. In 7 of our patients, we found a change in the King classification which seemed to be related to insufficient lumbar correction at the start of brace treatment. When classifying idiopathic scoliosis, one should bear in mind that the result may be temporary because scoliosis is a dynamic process. A change in curve type can occur during brace treatment.