Chiari malformation is a condition in which the brain tissue of the cerebellar tonsils has herniated into the cervical spinal canal. More information on this condition can be seen in the "Anatomy and Causes" section of this web site. Because of CSF circulation blockage by Chiari malformation, CSF can accumulate in the spinal cord itself and cause syringomyelia. Hydrocephalus can develop as well.

Classic conventional treatment is surgical decompression that consists of bone removal at the occipital bone and spine, and enlargement of dural covering at the craniospinal juncture with dura graft placement. Syringomyelia usually resolves when adequate Chiari decompression is performed. If syringomyelia does not resolve by Chiari decompression, a shunt catheter has to be placed in order to drain the accumulated fluid in the spinal cord.