Dynamic evaluation of the cervical spine by kinematic MRI in patients with cervical spinal cord injury without fracture and dislocation

BACKGROUND: The pattern of changes in the cervical spine and the spinal cord and their dynamic characteristics in patients with cervical spinal cord injury without fracture and dislocation remain unclear. This study aimed to evaluate the dynamic changes in the cervical spine and spinal cord from C2/3 to C7/T1 in different positions by using kinematic magnetic resonance imaging in patients with cervical spinal cord injury without fracture and dislocation. This study was approved by the ethics committee of Yuebei People's Hospital. METHODS: Using median sagittal T2-weighted images for 16 patients with cervical spinal cord injury without fracture and dislocation who underwent cervical kinematic MRI, the anterior space available for the cord, spinal cord diameter, posterior space available for the cord from C2/3 to C7/T1, and Muhle’s grade were determined. The spinal canal diameter was calculated by adding the anterior space available for the cord, spinal cord diameter, and posterior space available for the cord. RESULTS: The anterior space available for the cord, posterior space available for the cord, and spinal canal diameters at C2/3 and C7/T1 were significantly higher than those from C3/4 to C6/7. Muhle’s grades at C2/3 and C7/T1 were significantly lower than those at the other levels. Spinal canal diameter was lower in extension than in the neutral and flexion positions. In the operated segments, significantly lesser space was available for the cord (anterior space available for the cord + posterior space available for the cord), and the spinal cord diameter/spinal canal diameter ratio was higher than those in the C2/3, C7/T1, and non-operated segments. CONCLUSION: Kinematic MRI demonstrated dynamic pathoanatomical changes, such as canal stenosis in different positions, in patients with cervical spinal cord injury without fracture and dislocation. The injured segment had a small canal diameter, high Muhle’s grade, low space available for the cord, and high spinal cord diameter/spinal canal diameter ratio.