Chiari Malformation

Gillette Children’s Specialty Healthcare offers comprehensive evaluations, treatments and services for children, teens and adults who have Chiari malformation. Because Chiari malformation is a complex condition that affects each person differently, we provide a wide range of services to meet the needs of our patients.

Why Choose Gillette?

  • Gillette is a regional leader in pediatric neurosurgery and neurology.
  • We offer an extensive, interdisciplinary team of experts who provide patients with customized treatment plans.
  • Our facilities and technology are designed specifically for people who have complex conditions and disabilities.
  • We believe that people who have Chiari malformation deserve a lifetime of excellent health care—from birth through adulthood.
  • We are committed to helping our patients achieve their highest possible levels of comfort, independence and happiness.


A Chiari malformation occurs when the cerebellum (back of the brain) develops abnormally and protrudes into the spinal canal. The downward movement of the brain tissue puts pressure on the cerebellum, limiting the flow of cerebrospinal fluid (a protective liquid that surrounds the brain and spinal cord). This pressure can prevent parts of the brain and spine from functioning properly. It sometimes causes problems with balance and coordination.

Types of Chiari Malformations

Chiari malformations are categorized into several groups, depending on which parts of the brain push down into the spinal canal.

  • Type I: The cerebellum pushes through the bottom of the skull into the upper spinal canal. Symptoms might not appear until adolescence or early adulthood. It is the most common type of Chiari malformation in children.
  • Type II (Arnold-Chiari malformation): In this type, a greater portion of the cerebellum and part of the brain stem push into the spinal canal. This type is nearly always associated with myelomeningocele, a severe form of spina bifida.

Types III and IV are extremely rare.

  • Type III: Parts of the cerebellum and brain stem protrude into the spinal cord, sometimes causing a pouch-like structure to form on the back of the neck. It is one of the most severe forms of the condition and often causes life-threatening complications.
  • Type IV: Also called cerebellar hypoplasia, this type occurs when the cerebellum does not completely develop. It is the most severe form of the condition. Most infants born with Type IV Chiari malformation do not survive.

Chiari Malformation Symptoms and Effects

Sometimes people who have Chiari malformation do not experience any symptoms or symptoms might not appear until later in adolescence or adulthood.

Symptoms of Type I Chiari malformation might include:

  • Headaches
  • Pain in the arms, legs or neck
  • Numbness or weakness in the hands and arms
  • Unsteadiness when walking
  • Dizziness
  • Vomiting
  • Loss of the ability to sense temperature
  • Curvature of the spine (scoliosis)
  • Syringomyelia—fluid collection in the spinal cord

In addition, some younger children and infants might have difficulty drinking or swallowing.

Symptoms of Type II Chiari malformation resemble those of Type I, but are more severe and usually occur at a younger age. They include:

  • Abnormally slow or noisy breathing
  • Accidentally breathing fluids or saliva into the lungs
  • Numbness or weakness in nerves of the throat, face or tongue

Chiari Malformation Incidence, Causes and Risk Factors

Most people who have Chiari malformation are born with the condition. It occurs in about one of every 1,000 births. Chiari malformation often occurs with conditions such as hydrocephalus, craniosynostosis, Ehler-Danlos syndrome and Klippel-Feil syndrome.

Type 1, the most common type of Chiari malformation, is caused by abnormalities during fetal development that stem from genetic mutations or a lack of certain vitamins and nutrients in a mother’s diet. Secondary Chiari malformation typically occurs later in life and is caused by an injury, exposure to toxic substances or an infection.

Chiari Malformation Tests and Treatments

Some Chiari malformations don’t cause symptoms and therefore don’t require treatment. Other patients who have the condition might experience a wide range of symptoms. At Gillette, our team of experts collaborates with other specialists to diagnose the condition. We also work closely with patients and their families to create comprehensive care plans. 

We start with a review of a patient’s medical history. Some of the tests used to diagnose Chiari malformation include:

  • MRI scan of the brain
  • CT scan

Treatments for Chiari malformation include:


Pain-relieving or anti-inflammatory medications address the frequent headaches and pain that are common symptoms of Chiari malformation.


Our pediatric neurosurgeons work closely with patients and families to determine if someone who has Chiari malformation could benefit from surgery. The surgery for Chiari malformation, called posterior fossa decompression, increases space for the cerebellum and brain stem, relieving pressure on the brain and allowing cerebrospinal fluid to flow normally. If a patient also has hydrocephalus—especially in combination with spina bifida and Type II Chiari malformation— the patient might need shunt surgery first to treat the hydrocephalus.

Our Chiari Malformation Services

The different symptoms and effects of Chiari malformation require a team approach to care. That’s why Gillette has experts in a wide range of specialties and services.

A patient who has Chiari malformation often sees experts in the following specialties and services:

For information about the comprehensive services we provide at Gillette, search Conditions and Care.

Publications and Resources Related to Chiari Malformation

Meet Nolan

Find out how we're moving Nolan forward.

Read Nolan's Story ยป