Chiari malformation (kee-AH-ree mal-for-MAY-shun) is a condition in which brain tissue extends into your spinal canal. It occurs when part of your skull is abnormally small or misshapen, pressing on your brain and forcing it downward.
People with myelomeningocele, the most serious form of Spina Bifida, have abnormalities that are not limited to their spinal cord. These include the development of symptoms related to the area where the brain and spine join, known as Chiari malformation.
Chiari Type II or Arnold-Chiari malformation, is a more severe form in which the cerebellar vermis and some portion of the brain stem descend into the cervical spine. Many changes of the brain are associated with this abnormality. Although some degree of this malformation is present in the vast majority of people with Spina Bifida, it appears to be symptomatic in about one of three individuals.
This information sheet provides:
- an explanation the nature of Chiari Type II and its symptoms,
- a review of tests done for Arnold Chiari malformation, and
- a description of surgical options.
This information does not constitute medical advice for any individual. As special cases may vary from the general information presented here, SBA advises readers to consult a qualified medical or other professional on an individual basis.