C0–2 Cobb angle was measured as the angle between the McGregor line and lower endplate of the C2 vertebra. A positive value indicates lordosis between the occiput and C2, and a negative value indicates kyphosis between the occiput and C2. C2-C7 sagittal vertical axis (SVA) was the horizontal distance between the C2 plumb line and the posterior corner of C7.