A comparative study of curve flexibility assessment in supine traction, push-prone and push-prone traction radiographs in adolescent idiopathic scoliosis.

Study Design: A prospective comparative study.

Objectives: To compare the curve flexibility in adolescent idiopathic scoliosis (AIS) using supine traction push-prone and push-prone traction radiographs and to determine which method is more effective in predicting the postsurgical correction.

Background: Preserving spinal motion is one of the critical objectives in adolescent idiopathic scoliosis (AIS) surgery. Hence, evaluating curve flexibility preoperatively is crucial in determining the optimal instrumented level. Supine lateral side bending radiographs are commonly considered the gold standard for assessing curve flexibility. Several methods are employed to determine curve flexibility, including supine traction, push-prone, and fulcrum bending radiographs. Nonetheless, the combined application of the push-prone and traction techniques for evaluating curve flexibility has not been documented, and the effectiveness of curve correction utilizing this approach remains uncertain.

Methods: Between 2021 and 2024, AIS patients who underwent posterior spine surgery were enrolled in the study. Preoperative 36-inch whole spine radiographs, including posteroanterior, supine traction, push-prone, and push-prone traction views, were obtained. Demographic data, including sex, age, BMI, Lenke's curve type, and pre-and postoperative major Cobb angle, were collected. Major curves, including proximal thoracic, main thoracic, and thoracolumbar/lumbar curves, were assessed using various techniques. The mean absolute difference of the major Cobb angle for each method was analyzed to establish a confidence interval. Additionally, the curve flexibility ratio was evaluated through radiographic analysis. The correction index was calculated by dividing the correction rate by the flexibility for each technique.

Results: A total of one hundred and six AIS patients (96 female and 10 male) with a mean age of 14.9 ± 2.3 years were identified. The combined push-prone and traction method demonstrated the highest flexibility in assessing the overall, PT, MT, and TL/L curves, followed by supine traction and push-prone methods. Moreover, the correction index also shows that the push-prone traction method provides the best predictive outcome for postoperative results compared to supine traction and the push-prone method.

Conclusion: Our analysis shows that push-prone traction radiographs provide the highest curve flexibility and are more reliable in predicting curve correction in AIS patients who underwent posterior spine surgery.