Stenosis and movement of the cervical spine in cervical myelopathy.

The width of the spinal canal in 55 patients with cervical myelopathy was compared to a control group of 225 patients without myelopathy. There was a statistically significant narrowing of the cervical canal in the patients with cervical myelopathy, especially in men. Neck movement in the sagittal plane was studied in pantopaque myelograms in 43 patients with cervical myelopathy. It was found that retroflexion causes the most severe narrowing of the spinal canal. Patients with congenital cervical stenosis showed the greatest changes. Sagittal movement of the cervical spine was measured 1--3 years after the Cloward fusion operation in 38 patients and compared to a corresponding age group of 33 and a younger group of 26 healthy controls. The fusion of two or more vertebrae leads to considerable limitation of sagittal movement of the cervical spine on the average of 23,5 degrees in comparison with 40,6 degrees in the corresponding age control group. With the increasing age, anteflexion and retroflexion deteriorate equally, whereas the fusion operation restricts mainly the retroflexion of the cervical spine. In fact, the therapeutic effect of the Cloward operation seems to lie in the restriction of movement of the cervical spine.