STUDY DESIGN: Systematic Review and Meta-analysis. OBJECTIVES: This systematic review and meta-analysis aimed to: (1) synthesize the prevalent application ratios of 2 radiographic spinal flexibility assessment methods in AIS patients treated with PSF or bracing
and (2) quantitatively evaluate the accuracy of these methods in predicting post-intervention correction outcomes. METHODS: A systematic search was conducted across 5 electronic databases: CINAHL, Embase, Ovid, PubMed, and Web of Science. Meta-analyses were performed to investigate the accuracy of the spinal flexibility rate in predicting the post-intervention correction rate in AIS patients treated with PSF surgery or bracing, using RevMan 5.4.1 software. RESULTS: The results of 31 studies, involving 1868 AIS patients, showed that the side-bending method was utilized more frequently than the fulcrum-bending method in both treatments. Meanwhile, the spinal flexibility evaluated by the fulcrum-bending method may provide a more accurate prediction of post-surgical correction compared to the side-bending approach, particularly for main curves. For the bracing treatment, only a few studies have preliminarily reported good capability of the side-bending method in predicting the initial in-brace correction. CONCLUSIONS: This review quantitatively assessed the clinical application ratio and effectiveness of side-bending and fulcrum-bending radiographs in predicting post-intervention curve corrections in AIS patients undergoing surgical or bracing treatments. The results of the current review supported to adopt the fulcrum-bending approach for AIS patients undergoing PSF surgery with main thoracic curves, and the side-bending approach for those with thoracolumbar/lumbar curves. For patients receiving bracing treatment, further research is still needed to confirm the clinical value of the side-bending method.