Age-related degenerative changes and sex-specific differences in osseous anatomy and intervertebral disc height of the thoracolumbar spine

The aim of this study was to determine age-related changes and sex-specific differences in sagittal alignment, range of motion (ROM), and intervertebral disc height of the thoracolumbar spine in healthy subjects. Lateral neutral and flexion–extension radiographs of the thoracolumbar spine of 627 asymptomatic subjects (307 males and 320 females; average age, 49.6 ± 16.5 years) were evaluated. We included at least 50 males and 50 females in each decade of life between the 20s and the 70s. Intervertebral disc height from T10/T11 to L5/S1, local lordotic alignment, and ROM from T10–T11 to L5–S1 were measured. T10–L2 kyphosis and T12–S1 lordosis as well as flexion, extension, and total ROM were measured. T10–L2 kyphosis did not markedly change with age in subjects of either sex but a sudden increase was noted in the 70s females. T12–S1 lordosis increased with age in both sexes, except the 70s. Flexion, extension, and total ROM at T10–L2 and T12–S1 decreased with age in most subjects. The levels from L3–L4 to L5–S1 were conspicuous as mobile segments. Intervertebral disc height gradually increased from T10/T11 to L4/L5; the shortest was at T10/T11 and the longest at L3/L4 or L4/L5 in all subjects. Age-related decreases in intervertebral disc height were most prominent at L4/L5 in middle-aged and elderly individuals of both sexes. Normative values of sagittal alignment, ROM, and intervertebral disc height at each segmental level were established in both sexes and all age groups in healthy subjects.