Magnetic resonance imaging study on the available space of the spinal cord in patients with developmental cervical stenosis and cervical spondylotic myelopathy

English Keywords:Cervical spondylosis  Developmental cervical stenosis  Available space for the spinal cord  MRI

English Abstract:

  【Abstract】 Objectives: To observe the intra-dural available space of the spinal cord in patients with developmental cervical stenosis and cervical spondylotic myelopathy by using magnetic resonance imaging. Methods: Among the 123 patients encountered for cervical spondylotic myelopathy in Peking University Third Hospital from February 2006 to July 2010, 66 patients without ossification of the posterior longitudinal ligament or the ligamentum flavum or vertebral osteophytes and with the occupation ratio of the herniated disc less than 50% were included in the study. There were 41 males and 25 females with age ranging from 34 to 84 years(average, 57 years). Based on their lateral radiographs, all patients were divided into two groups: developmental cervical stenosis group(stenosis group, n=38) and non-developmental cervical stenosis group(non-stenosis group, n=28). On the magnetic resonance images, the sagittal diameter of the dural sac and the vertebral body on T2-weighted sagittal images as well as the cross-sectional area of the spinal cord and the dural sac on T2-weighted transverse images from C3 to C7 were measured. Then the MRI Pavlov ratio(the sagittal diameter of the dural sac/the sagittal diameter of the vertebral body) and the occupation ratio(the cross-sectional area of the spinal cord/the cross-sectional area the dural sac) were calculated and compared. Results: The MRI Pavlov ratio of the stenosis group was lower than that of the non-stenosis group in C3-C7(P<0.001). While the occupation ratio in the stenosis group was higher than that of the non-stenosis group in C7(P<0.05), while no significant difference was noted in C3-C6(P>0.05). Conclusions: The sagittal diameter of the dural sac decreases significantly in developmental cervical stenosis, however this does not lead to a significant decrease of the intra-dural space available for the spinal cord.