Kinetic changes in the spinal cord occupation rate of dural sac in cervical spondylotic myelopathy.

The study aimed to establish the spinal cord occupation rate of the dural sac during flexion and extension. We measured the cross-sectional area of the dural sac and the spinal cord between C2/C3 and C7/T1 disc levels in 100 patients with cervical spondylotic myelopathy and 1211 asymptomatic subjects. The spinal cord occupation rate of the dural sac in the cross-sectional area was higher on extension than on flexion at the mid-lower cervical spine. The spinal cord occupation rate of the dural sac in the cross-sectional area was highest at the C4/C5 and C5/C6 levels on extension. [ABSTRACT FROM AUTHOR]