Prospective comparison of flexibility radiographs in adolescent idiopathic scoliosis

STUDY DESIGN: A prospective evaluation of radiographs in patients undergoing anterior spinal fusion or posterior spinal fusion for adolescent idiopathic scoliosis. OBJECTIVE: To determine the most effective preoperative radiographic method for evaluating coronal plane flexibility by comparing preoperative and postoperative correction. SUMMARY OF BACKGROUND DATA: Curve flexibility is traditionally evaluated with side-bending radiographs. Recently, the fulcrum-bending radiograph was shown to provide better correction of thoracic curves undergoing posterior spinal fusion but was not evaluated in thoracolumbar/lumbar curves or in patients undergoing anterior spinal fusion. METHODS: Preoperative coronal radiographs of 46 consecutive patients undergoing spinal fusion for adolescent idiopathic scoliosis obtained while standing, lying supine, side-bending (maximally bending while supine), push-prone (padded bolsters applied to chest wall while prone), and fulcrum-bending (curve apex suspended over a radiolucent fulcrum while lateral) were compared with standing postoperative radiographs. Cobb angles were determined and evaluated for statistical significance. RESULTS: The fulcrum-bending radiograph demonstrated statistically better correction than other preoperative methods for main thoracic curves (P < 0.01) but fell short of demonstrating the correction obtained surgically. There was no statistical difference between side-bending, fulcrum-bending, or postoperative correction for thoracolumbar/lumbar curves (all P values > 0.07). The left side-bending was the most effective method for reducing upper thoracic curves (P < 0.001). There was no difference in the results obtained for curves corrected by anterior spinal fusion or anterior spinal fusion. CONCLUSION: To achieve maximal preoperative correction, thoracic fulcrum-bending radiographs should be obtained for evaluating main thoracic curves, whereas side-bending radiographs should continue to be used for evaluating both upper thoracic and thoracolumbar/lumbar curves.