Chiari malformations are structural defects in the cerebellum, the part of the brain that controls balance and some other functions. This abnormal structure causes a portion of the posterior (rear) part of the brain to be compressed and to bulge and protrude into the spinal canal, which contains the spinal cord. The resulting pressure on the cerebellum and brain stem may affect functions controlled by these areas and block the flow of cerebrospinal fluid (CSF) — the clear liquid that surrounds and cushions the brain and spinal cord — to and from the brain.
Chiari malformations can be caused by structural defects in the brain and spinal cord that occur during fetal development. Chiari malformations also can be caused later in life if CSF is drained excessively from the spine either due to injury, exposure to harmful substances or infection.
Symptoms of Chiari Malformation
Symptoms of Chiari malformation vary and may change, depending on the buildup of CSF and resulting pressure on the tissues and nerves. Some people with CM may not exhibit any CM-related symptoms at all or may have only mild symptoms, which may not develop until later in life.
Adults with Chiari malformation may have one or more of a wide variety of symptoms:
- Headache and neck pain
- Balance problems
- Muscle weakness or numbness or other abnormal feelings in the arms or legs (known as paresthesia)
- Vision problems
- Difficulty swallowing (dysphagia)
- Ringing or buzzing in the ears (also called tinnitus) or hearing loss
- Difficulty falling or staying asleep (insomnia)
Infants with Chiari malformation may have one or more of a wide variety of symptoms:
- Difficulty swallowing
- Irritability when being fed
- Excessive drooling
- A weak cry
- Gagging or vomiting
- Arm weakness
- Stiff neck
- Breathing problems
- Developmental delays and/or inability to gain weight
Diagnosis of Chiari Malformation
Many people with a CM in the brain have mild symptoms or no CM-related symptoms at all. Therefore, because the symptoms of CM may not be present or may overlap with those of other more common diseases, CMs are often discovered during the diagnosis or treatment of another disorder. At Houston Methodist, our doctors will conduct an examination that includes a thorough look at your complete medical history and physical examination as well as tests using the most advanced magnetic resonance imaging (MRI) technology to confirm and evaluate CM. In addition, patients may undergo a specialized CSF flow study to evaluate the flow through the foramen magnum (the opening in the base of your skull through which the spinal cord passes).
Treatment Options for Chiari Malformation
Some patients with CM may not require treatment because the malformation does not interfere with normal daily activities; however, such patients should be followed closely by the neurologic team. In other cases, medications may ease certain CM-related symptoms, such as pain, and surgery may be an option.
If surgery is recommended, your surgeon will perform a posterior fossa decompression. During this procedure, a small portion of bone is removed from the back of the skull to make room for the brainstem and re-establish normal CSF flow (decompression).
Most patients who have surgery will have a reduction in their symptoms and increased periods of stability; however, more than one surgery may be needed to achieve optimal results.
Recovery and Rehabilitation From Treatment for Chiari Malformation
After surgery, you will be taken to a recovery room until you wake up and your vital signs (blood pressure, breathing rate) are stable. Then you will be moved to a regular hospital room or intensive care unit (ICU) room to further recover. Most patients are able to leave the hospital within a day or two.
Our team will instruct you on proper home care and follow-up visits after your treatment procedure. When you return home, make sure to follow your surgeons advice about returning to normal activities, taking care of the incision site and watching for any signs of infection such as fever, chills, unusual pain or bleeding or swelling at the incision site. You may need to have periodic exams or tests so your doctors can monitor your condition.
Our physicians at Houston Methodist specialize in managing Chiari malformation at the following convenient locations: