Arnold Chiari (pronounced key-are-ee) Malformation is a rare malformation of the brain located in the area where the brain and spinal cord connect. This malformation occurs when the cerebellum is too large to fit within the confines of the skull.
When the cerebellum is over-sized, the cerebellar tonsils are forced to extend down into the spinal cord canal through the small opening in the base of the skull. As the cerebellar tonsils elongate, they may restrict or cut off the normal flow of cerebro-spinal fluid of the brain and around the spinal cord as well as apply pressure to the brain stem and the top of the spinal cord. This condition is usually a congenital abnormality but there have been a few reported cases of spontaneous development due to trauma.
According to the Duke Center for Human Genetics, “The affected regions of the brain are the lower brainstem and cerebellum. The lower brainstem controls breathing, swallowing, balance, the vocal cords, eye movements, and sensation and movement of the arms and legs. The cerebellum’s most important function is to coordinate body movements.”
The symptoms of Chiari vary with each individual and are quite extensive. Most commonly, Chiari patients have some or all of the following symptoms:
Some patients with Chiari have no visible symptoms. For these patients, careful monitoring by a neurologist or neurosurgeon is all that is needed. These patients may live a full life with no adverse effects appearing. Other patients with the adult onset variety of Chiari Type-I will begin to exhibit symptoms in their late 20’s or 30’s. For most people who are exhibiting symptoms, surgery is the only option available to help stop the progression.
Generally, the surgery is meant to decompress the area of the brain that is being squeezed. Surgery to correct the malformation may not be able to reverse any neurological damage that has already been done. Once the pressure has been relieved, the patient may see some of their symptoms lessen or disappear.
The long-term effects of the surgery are still being studied. However, surgeons will not guarantee that symptoms will disappear after the surgery, or that symptoms, either old or new, will not return in the future. The main goal of the surgery is to attempt to prevent the patient from worsening from their current neurological status. For some patients, a second decompression surgery will be needed some years after the first surgery was completed.
As a person living with Chiari, I can not stress enough the importance of finding and staying with a neurosurgeon that specializes in dealing with Chiari. This is a complex disease. Receiving the wrong medical advice can be extremely detrimental to your health. To find qualified medical care near you, I suggest that you join a Chiari support group and ask the other members for their help and guidance.