Fig. 3. A 13-year-old girl with a single thoracic curve and lumbar modifier A. (A) Preoperative anteroposterior and lateral radiographs. She was treated with pedicle screw instrumentation from T4 to T12 and rod derotation with direct vertebral rotation; round arrow=direction of rod derotation, straight arrows=directions of direct vertebral rotation. The screw in the lowest instrumented vertebra was rotated in the direction opposite to screw rotation in the apical vertebra of thoracic curve. (B) Anteroposterior and lateral radiographs taken immediately after surgery. Good correction was obtained in the thoracic and lumbar curves. (C) Anteroposterior and lateral radiographs taken 2 years and 7 months after surgery. The adding-on deformity produced during the follow-up led to the loss of lumbar curve correction.