Pediatric Chiari malformation

What are pediatric Chiari malformations?

The cerebellum, located in the back of the brain, controls balance, coordination and fine motor movements. This part of the brain sits at the base of the skull above an opening called the foramen magnum. The spinal cord travels through this opening.

Chiari malformations happen when the part of the skull that holds the cerebellum is too small or unusually shaped. This allows the lowest part of the cerebellum to push into the foramen magnum opening.

Many children with Chiari malformations don’t have symptoms or need surgery. Sometimes, pressure on the brain or brainstem, or a blockage of cerebral spinal fluid, causes problems that require surgery.

Chiari malformation was named after an Austrian pathologist Hans Chiari in 1981 after publishing a paper describing the malformation of the cerebellum and brainstem in a 17 year old female.

What are the different types of pediatric Chiari malformations?

There are different types of pediatric Chiari malformations. Some types don’t cause symptoms, while others cause life-disrupting (and sometimes life-threatening) problems.

At Children's Health, we provide care for kids with all types of Chiari malformations including:

• Chiari malformation Type 0 - The cerebellum looks normal on an MRI, but there’s a fluid-filled cyst within the spinal cord (syringomyelia) due to a blockage in the brain’s lowest chamber.

• Chiari malformation Type 1 - Type 1 is the most common Chiari malformation. It happens when the lowest part of the cerebellum protrudes into the spinal canal. Many children with this type don’t have symptoms or they develop symptoms during their teen or adult years.

• Chiari malformation Type 2 - Type 2 or classic Chiari malformation occurs with a type of spina bifida called myelomeningocele. The tail end of the spinal canal doesn’t close, allowing the spinal cord to stick out from an infant’s back. Spinal fluid escapes from the spinal canal, and the cerebellum and brainstem sag lower in the skull, often moving into the upper spinal canal.

  • A child with Type 2 may have other brain and brainstem problems like hydrocephalus (excess spinal fluid buildup in the brain). Paralysis may also occur below the spinal canal opening.

• Chiari malformation Type 3 - Part of the cerebellum and brainstem bulge through an opening in the back of the skull (encephalocele) that shouldn’t be there.

• Chiari malformation Type 4 - The cerebellum is severely underdeveloped (cerebellar hypoplasia).

What are the signs and symptoms of pediatric Chiari malformations?

Symptoms of Chiari malformations in children vary depending on the type and cause. Types 1 and 2 are the most common Chiari malformations.

Symptoms of Chiari malformation Type 1

Chiari malformation Type 1 doesn’t always cause symptoms during childhood. Some kids never have any problems. Doctors often detect the condition after ordering imaging scans for another problem like chronic headaches, epilepsy or scoliosis (curvature of the spine).

• Bladder or bowel problems due to syringomyelia

• Central sleep apnea

• Dysphagia (swallowing disorder)

• Vocal cord dysfunction

• Occipital headaches felt at the base of the skull or back of the neck that get worse when a child laughs, coughs, sneezes or is physically active

Symptoms of Chiari malformation Type 2

Chiari malformation Type 2 often occurs with spina bifida and hydrocephalus. These conditions affect multiple parts of the body. Spina bifida can cause partial or complete paralysis below the spinal opening.

Rarely, a child may develop vocal cord paralysis due to lower brainstem problems. This is a life-threatening problem that requires immediate treatment.

How are pediatric Chiari malformations diagnosed?

Our neuroradiologists have deep expertise diagnosing Chiari malformations in children. Our ability to detect these conditions early is one of many reasons why the pediatric patients at Children’s Health do so well. We identify the condition quickly so surgeries happen before more serious problems develop.

We use these tests to diagnose all types of Chiari malformations in children:

• MRI - Used to assess brain anatomy.

• CT scan and X-rays - Used to identify bone abnormalities at the skull base and spine.

• Sleep studies - Used to diagnose sleep apnea.

• Video fluoroscopy - Used to check for swallowing problems (dysphagia).

• Prenatal MRIs and ultrasounds - Used to detect Chiari malformations in unborn children.

What causes pediatric Chiari malformations?

Chiari malformations are a congenital neurological disorder, meaning a child is born with the condition. For unknown reasons, an unborn baby’s brain and spinal cord don’t develop properly in the womb (in utero). Some people develop Chiari malformation Type 1 later in life. This is known as acquired or secondary Chiari malformation.

Potential causes include:

• Basilar invagination (the bone at the top of the spine pushes up toward the skull base)

• Brain tumors and cysts

• Head trauma

• Hydrocephalus

• Spinal fluid leak

How are pediatric Chiari malformations treated?

We diagnose and treat Chiari malformations in hundreds of children every year. We have deep surgical expertise treating the most complex malformations. This depth of experience contributes to our higher-than-average success rates, helping kids relieve symptoms and live healthy, active childhoods. In fact, U.S. News & World Report rates our pediatric neurology and neurosurgery program among the nation’s top programs.

Treatment includes:

• Fossa decompression surgery (chiari decompression surgery) - Our neurosurgeons perform posterior fossa decompression surgery to open the space at the skull base. The brain and brainstem have more room, which allows spinal fluid to flow more freely. Different procedures may take place during this surgery, but not every child needs each step. We tailor treatment based on your child’s unique anatomy and condition.

• Other - For children who have Chiari malformations and spina bifida, we partner with experts at the Pediatric Spina Bifida and Neurogenic Bladder Center. Your child receives care at one of the nation’s largest and most experienced pediatric spina bifida centers. We have advanced training in complex spinal fusions.

• After care - After surgery, your child recovers on our dedicated pediatric neurosurgical floor. Our nurses specialize in helping children like yours get better after neurosurgery.