When is a headache not “just a headache”? For about one in a hundred people, the answer may lie in a disorder called a Chiari malformation.
A Chiari malformation occurs when, during the brain’s development, the lower part of the brain moves abnormally downward into the area housing the spinal cord.
In two articles in a recent issue of Neurosurgery Clinics of North America, Dr. Richard C.E. Anderson and his colleagues, including former Columbia neurosurgery resident Dr. Todd Hankinson and current resident Dr. Hannah Goldstein, reported on the different approaches to treatment of Chiari 1 malformations.
The cerebellum is an area located at the lower part of the brain. Its main role is to coordinate how we move. It consists of 2 lobes. On the bottom side of the cerebellum near the opening of the skull are 2 small lobes called the cerebellar tonsils. In a Chiari 1 malformation, the cerebellar tonsils are pushed downward through the opening of the skull into the spinal canal.
Generally, people with a Chiari 1 malformation will have no idea that they have it early on. However, as they grow older during childhood and adolescence, they may develop a variety of symptoms.
Most commonly they may begin to have headaches (particularly at the back of the head) or neck pain, often made worse with straining. They may also have clumsiness, or weakness of their hands, or difficulty walking steadily.
In addition, the nerves arising from the brain and spinal cord may not work correctly. Depending on which nerves are affected, this may lead to problems such as a hoarse voice, difficulty swallowing and muscle weakness.
In the Neurosurgery Clinics of North America articles, Dr. Anderson and colleagues describe two different surgical treatments for Chiari 1 malformations: posterior fossa decompression and anterior decompression.
Posterior fossa decompression is the most commonly performed procedure. It involves entering the area of the lower brain and upper spinal cord through the back of the head and neck.
Surgeons then remove a small amount of bone from the lower skull and upper spine. This relieves the symptoms by reducing pressure around the brain and nerves. Only in rare cases of associated spinal instability are screws and rods needed to stabilize the area.
A different technique, known as anterior decompression, is typically reserved for patients with more severe symptoms and whose imaging studies show compression on the brainstem from the front rather than the back.
In many of these patients, the bones of the upper spine will press on the lower part of the brain stem, preventing some nerves from working well. Historically, in anterior decompression the doctors would make an incision through the mouth and upper throat area to reach the bony areas.
Modern surgical advances have made it possible to reach these same areas using an endoscope—a small tube passed through the back of the nose. Surgeons can view the affected area and perform the necessary procedure through the tube. Since surgeons do not enter the throat area during this procedure, patients can eat and drink sooner after surgery and recover more quickly.
Not everyone with a Chiari 1 malformation will have problems. Indeed, some with the condition will never know they have it. Among those who do have symptoms, many will not need surgery. However, as Dr. Anderson and his associates describe in the articles, advances in surgery have made it possible to improve many of the symptoms associated with Chiari 1 malformations.
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