Fig. 4. 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 T3 to L1 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 same direction as 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 after surgery. The correction was well maintained without adding-on deformity.