Three-dimensional surgical correction analysis in adolescent idiopathic scoliosis treated with posterior fusion

Posterior fusion is a key procedure for correcting severe adolescent idiopathic scoliosis (AIS). Three-dimensional (3D) assessment using low-dose stereoradiography is increasingly utilized to evaluate deformities. This study investigates the immediate correction magnitude in all three planes after posterior fusion.

Forty-four AIS patients underwent posterior fusion and were stratified into thoracic, thoracolumbar, and lumbar subgroups based on structural curve topography. Full-spine 3D reconstruction via stereoradiographic software was performed pre- and postoperatively.

Surgical correction resulted in significant changes across all planes. The Cobb angle correction ranged from 36.5° to 39°. Sagittal parameters remained largely unchanged, except for T1SPi (p = 0.05) and T9SPi (p = 0.007). Coronal and sagittal vertebral tilt significantly improved in all subgroups (p ≤ 0.05). Apical vertebral rotation (AVR) was highly significantly reduced (p ≤ 0.001), achieving vertebral detorsion of 55 %-69 %. Axial vertebral derotation and detorsion were noted at specific levels for all curve types.

Posterior fusion effectively corrects AIS in all three planes, achieving substantial coronal correction while maintaining sagittal balance. Significant axial derotation may help reduce postoperative cosmetic deformities, such as rib hump prominence. These findings highlight the importance of 3D assessment for a more comprehensive evaluation beyond Cobb angle measurement. Integrating stereoradiography into surgical planning may enhance correction strategies and improve long-term functional and aesthetic outcomes for AIS patients.