Evaluation of imaging methods for predicting the correction of scoliosis

Abstract：BACKGROUND: Various imaging methods are used for scoliosis evaluation, such as supine, traction, push-prone and lateral-bending radiographs.In recent years, fulcrum bending radiograph has become a new method for assessing the spinal flexibility.OBJECTIVE: To compare the value of standing bending, suspension traction and fulcrum bending radiographs in the prediction of scoliosis correction.DESIGN: A randomized controlled study was performed.SETTING and PARTICIPANTS: The study was completed in the Department of Orthopaedics, Peking Union Medical College Hospital. Twenty-seven hospitalized patients with idiopathic scoliosis, including 17 females and 10males, were selected for the study, with a mean age of 15.4 years.INTERVENTIONS: Preoperatively, all of the patients had examinations with lateral whole-spine radiograph, lateral bending radiograph, suspension traction radiograph and fulcrum bending radiograph, before posterior spinal fusion surgery was performed for correcting idiopathic scoliosis, using segmental internal fixation system of the third generation.MAIN OUTCOME MEASURES: The Cobb angle was measured for each thoracic curve on preoperative lateral, active lateral bending, standing bending, traction, and fulcrum bending radiographs as well as on postoperative radiograph.RESULTS: The mean postoperative Cobb angle was 31° on radiograph,significantly improved in comparison with that of thoracic curves on the preoperative radiograph(61°, t = 1. 706, P ＜ 0.01), with a mean reduction by 51.6%. In the thoracic curves, the postoperative Cobb angle was positively correlated with the preoperative Cobb angle measured on the standing bending, traction and fulcrum bending radiographs( P ＜ 0. 01). There was no significant difference between the mean Cobb angle on fulcrum bending and that on postoperative radiograph( P ＞ 0. 05), and significant difference was found between the other two methods and the postoperative mean Cobb angle ( P ＜ 0. 01).CONCLUSION: The fulcrum bending radiograph can be used to assess the flexibility of the thoracic curve, and its effect is better than that of standing bending radiograph and traction radiograph; these three methods must be combined to analyze scoliosis and predict scoliosis correction.