Chiari malformation 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. Chiari malformation is uncommon, but increased use of imaging tests have led to more frequent diagnoses. Treatment depends on the form, severity and associated symptoms. Regular monitoring, medications and surgery are treatment options. In some cases, no treatment is needed.
In the most common surgery for Chiari malformation, called posterior fossa decompression, your surgeon removes a small section of bone in the back of your skull, relieving pressure by giving your brain more room.