Hirofumi Matsumoto

Atlantoaxial subluxation associated with ossification of posterior longitudinal ligament of the cervical spine.

Study Design. Two case reports. Objective. To demonstrate two rare cases of atlantoaxial subluxation associated with ossification of the posterior longitudinal ligament of the cervical spine, in which spastic quadriplegia developed. Summary of Background Data. There are only two reports of an association of diffuse idiopathic skeletal hyperostosis with atlantoaxial subluxation. This condition often accompanies ossification of the posterior longitudinal ligament of the cervical spine, but there is nothing in the literature about the association of ossification of the posterior longitudinal ligament with atlantoaxial subluxation. Methods. Clinical and radiographic findings of these two cases were demonstrated. In both cases laminoplasty of the cervical spine was performed with occipitoaxial arthrodesis. Results. The spastic quadriplegia of these two patients caused by myelocompression improved after surgical intervention. Conclusion. Ossification of the posterior longitudinal ligament of the cervical spine may cause atlantoaxial subluxation.