Transoral surgery for basilar impression.

A patient with basilar impression presented with a progressive myelopathy due to odontoid invagination. It was thought that a posterior decompression would be hazardous; therefore, the inferior clivus, odontoid process, and anterior arch of the atlas were removed transorally. We have found that, even with symptoms of long duration, marked improvement can be expected when the operation is targeted to the actual abnormality. In such cases, analysis of craniocervical tomograms will show the direction of medullary compression and thus indicate the correct surgical approach.