The role of dynamic MRI of the cervical spine and dynamic evoked potentials in the diagnosis of degenerative cervical myelopathy
Abstract
The study evaluates the effect of flexion and extension of the cervical spine assessed using dynamic MRI on spinal cord functions assessed using dynamic evoked potentials (EPs) in healthy individuals (group 1) and in patients subjectively and objectively with a mild form of degenerative cervical myelopathy without graphic signs of spinal cord compression on static MRI (group 2). Methods: 10 individuals were included in group 1 as well as in group 2.
MRI and EPs were performed in neutral position, flexion and extension. The anterior and posterior length of the spinal cord, the transverse and anteroposterior dimensions and the area of the spinal cord were measured on the MRI of cervical spine.
Somatosensory EPs of the median nerve and tibial nerve and motor EPs from the muscles of the upper and lower limbs were recorded. Results: In group 2, compared to group 1, we noted a change in spinal cord functions, length and shape of the spinal cord in the neutral position.
During flexion and extension, in group 2, as well as in group 1, there was a change in anterior and posterior length, and in contrast to group 1, there was also a decrease in the transverse and anteroposterior dimensions and area of the spinal cord in the C4/ 5 and C5/ 6 segments. In addition, somatosensory EPs and motor EPs were altered as well.
Conclusion: Movements of the cervical spine cause a change in the shape and function of the spinal cord, differently in healthy individuals and patients with mild degenerative cervical myelopathy.