Discussion on Surgical Treatment in Cervical Myelopathy due to Ossification of the Posterior Longitudinal Ligament

42 patients with cervical myelopathy due to ossification of the posterior longitudinal ligament have been treated in our clinic since 1953. There were 34 males and and 8 females, and 21 cases in the segmental type of ossification, 6 in the continued type and 15 in the mixed type.Anterior approach was done in 17 cases to remove the ossification and poserior approach was taken in 19 cases. In 2 cases posterior approach was performed after the vertebral bodies were fused.There is no difference in the results between the anterior approach and the posterior approach.Dynamic roentgenogram is useful for determination of the indication. There are two types of the cases with movable or non-movable intervertebral space in which myelographic filling defect was seen during flexing the cervical spine. The anterior approach is indicated in the movable type. Either the anterior approach or the posterior approach is taken in the non-movable type.