The behavior of the unfused lumbar curve following selective thoracic fusion for idiopathic scoliosis.

The behavior of the unfused lumbar curve was evaluated radiographically in 58 cases of adolescent idiopathic thoracic scoliosis that had a selective thoracic fusion only. The lumbar scoliosis echoed the correction obtained in the thoracic scoliosis both immediately postoperatively and at an average 2 1/2-year follow-up. In the sagittal plane, although correction was obtained in the thoracic hypokyphosis, there were no changes seen in the lumbar lordosis at final follow-up. Segmental instrumentation was more effective in correcting thoracic scoliosis and hypokyphosis, but did not alter the behavior of the lumbar curve. The caudal extent of the fusion relative to the stable vertebra did not measurably alter the operative results in either curve or plane.