Evaluation of sagittal alignment and range of motion of the cervical spine using multi-detector- row computed tomography in asymptomatic subjects.

To evaluate the sagittal alignment and range of motion (ROM) of the cervical spine during cervical flexion and extension ,using multi-detector-row-computed tomography (MDCT) in asymptomatic subjects.Understanding the normal alignment and range of motion of the cervical spine is very important while evaluating patients with cervical spine instability and abnormal alignment. Several reports using plain radiographic data have assessed the alignment and ROM of the cervical spine during flexion and extension. However, there has been no such report using MDCT. Ninety-eight subjects who did not have cervical spine-related symptoms were enrolled. After myelography, all subjects underwent cervical MDCT in cervical flexion and extension. Sagittal alignment and ROM between C2 and C7 were measured.The sagittal alignment between C2 and C7 was -11.7°±8.3° (mean ± standard deviation) in flexion and 26.5°± 12.9° in extension. The C5/6 level showed maximum kyphosis in flexion. The C6/C7 level demonstrated maximum lordosis in extension. ROM between C2 and C7 was 37.9°±11.2°. The C2/3 level showed the lowest ROM and the C5/C6 level showed the highest ROM among the intervertebral levels evaluated.The sagittal alignment and ROM of the cervical spine during flexion and extension in asymptomatic subjects were measured using MDCT. Each level between C2 and C7 could be evaluated in detail without any influence due to degenerative changes in the spine or soft tissues of the shoulder. MDCT generated a more precise understanding of the dynamic changes at each evaluated intervertebral level in the cervical spine. Level of Evidence : Level II.