What is a Chiari malformation?
Chiari malformations occur at the base of the skull and involve a part of the brain called the cerebellum. The cerebellum controls posture, balance and voluntary movements. When a Chiari malformation is present, the cerebellum and occasionally part of the brainstem is squeezed through an opening into the spinal canal. This puts pressure on the brain and spinal cord, causing symptoms with a variety of severity.
What are the types of Chiari malformations in children?
The different types of Chiari malformations are classified based on the severity of the symptoms and the parts of the brain that extend into the spinal canal.
- Chiari malformation Type I (CM-I) – The most common type of Chiari malformation is Chiari I malformation. The cerebellum extends into the canal opening. Type I is most often congenital, which means it is present at birth, but usually doesn’t present symptoms until adolescence or young adulthood.
- Chiari malformation Type II (CM-II, Arnold Chiari malformation) – Chiari II, also known as classic Chiari malformation or Arnold Chiari malformation, occurs when the cerebellum and possibly the brainstem bulge through the opening at the base of the skull into the spinal canal. Chiari II malformation is also congenital, and it is seen with spina bifida.
What causes Chiari malformations?
The cause of congenital Chiari malformations is unknown. Generally, it occurs when there is insufficient space in the skull to accommodate the cerebellum.
What are the symptoms of Chiari malformations?
The most common symptom of Chiari I malformation is headaches that cause pain in the back of the head or neck. The pain may become worse with laughing, sneezing or coughing. Other symptoms of CM-I include:
- Hoarseness or trouble speaking
- Trouble swallowing
- Rapid, back-and-forth eye movements (nystagmus)
- Periods of not breathing during sleep (sleep apnea)
- Weakness; abnormal movements or reflexes
- Trouble with balance
- Scoliosis (curvature of the spine)
Chiari II malformations are typically diagnosed in newborns or infants. This is due to the severity and the fact that other defects may require additional screening, revealing the malformation. Other symptoms for CM-II include:
- Spina bifida
- Spinal myelomeningocele (part of the spinal cord and backbone develop outside the body)
- Noisy breathing
- Trouble swallowing
- Problems with breathing food or fluid into the lungs (aspiration)
- Short periods of not breathing (apnea)
- Weakness in the arms
Additional symptoms in older infants and children may include:
- Hydrocephalus that gets worse over time
- Vision problems or hearing loss
- Trouble with motor skills in their hands
With any type of Chiari malformation, an additional condition called a syrinx—a collection of spinal fluid in the spinal cord—might occur, triggering other symptoms like weakness, numbness and bowel problems.
What are the treatment options for a Chiari malformation?
At first, your doctor may recommend careful watching and medication to soothe the pain and headaches. However, surgery is the most effective way to alleviate the pain and minimize the risks of additional complications that arise from Chiari malformations and related conditions.
The procedure to treat Chiari malformations is called posterior fossa decompression, or sometimes just Chiari decompression. It involves removing a part of the occipital bone at the base of the skull through a small incision that is made on the back of the head. This allows more space for the cerebellum and brainstem, and lessens pressure on the brain and spinal cord.
If necessary, the surgeon will also open the dura, the protective covering around the brain and spinal cord, to allow for more free space. A graft (replacement tissue) is used to expand the dura, similar to letting out the waistband on a pair of pants.
The surgery lasts about two hours, and recovery time varies depending on the age of the patient and other factors. In most cases, surgery completely resolves the pain and discomfort of Chiari malformation.
Our board-certified surgeons have experience from the most routine to rare surgical procedures. Whether your child has a Chiari malformation or multiple conditions requiring several operations, our team will work with your family to ensure you are informed, prepared and comfortable from pre-surgery through recovery.
When to Seek Help for a Chiari Malformation
If you notice any changes in your child’s ability to breathe, swallow, feed, speak, walk or move, call your health care provider. In older children, a headache that worsens with sneezing, coughing or laughing may indicate a problem.