Figure 2

Simulated coronal correction using the 3D segmented spine model. A: Before correction of the L5 vertebra. B: After correction of the L5 vertebra. The coronal correction was performed by rotating the vertebra around an axis consisting of intersecting points between the mid-sagittal plane and the anterior and posterior margin of the upper endplate of the lower vertebra (S1), thus constraining the correction to the coronal plane (A). The correction was continued until the upper endplate of the L5 vertebra became horizontal (B).