Fig. 1.

(A) The anterior segmental height (ASH) and posterior segmental height (PSH) were measured as the distance between the upper end plate of the upper vertebra and the lower end plate of the lower vertebra at the anterior and posterior margins, respectively. (B) The cage distance was measured as the distance between the anterior edge of the upper vertebra and the anterior margin of the cage. (C) Magnification differences were corrected by the ratio between the anteroposterior diameters at the middle of the upper vertebral body on each plain radiograph (A-a) and MRI (B-b). Every length measured on the plain radiographs was multiplied by the ratio (B-b/A-a). (D) Segmental lordosis was measured using Cobb's method.