Chiari Malformations

If you or a loved one is experiencing a Chiari malformation – a condition affecting the cerebellum at base of the brain, you want prompt attention and top-quality care and treatment in neurosciences, which encompasses neurology and neurosurgery. That’s exactly what you’ll find at OU Health.

Types of Chiari Malformation

There are four types of Chiari malformation. They are based on how severe the condition is and how much of the brain is affected:

Chiari Malformation Type I

• Type I is the most common form
• The bottom part of the cerebellum, called the cerebellar tonsils, dips into the bottom of the skull called the foramen magnum and can affect how the brain and spinal cord work and block the flow of the fluid that surrounds them
• The cerebellum is the part of the brain that controls balance
• Many people with type I may have no symptoms
• In some cases, the condition is found only through imaging tests

Chiari Malformation Type II

• Parts of the cerebellum and the brain stem may be in the foramen magnum
• This type is often noticed in infancy
• Type II tends to block the flow of cerebrospinal fluid (CSF) between the brain and spinal cord, causing more serious symptoms
• Type II is nearly aways linked with a spine malformation called a myelomeningocele

Chiari Malformation Type III

• Type III is very serious and life-threatening
• It's found during fetal ultrasound or at birth
• Parts of the brain and brain stem may stick out of a hole in the back of the skull

Chiari Malformation Type IV

• Type IV is also known as cerebellar hypoplasia
• In this rare condition, the cerebellum doesn’t completely form
• Babies born with type 4 may have other skull or spinal cord defects

What Are Symptoms a of Chiari Malformation?

The symptoms of a Chiari malformation may vary person to person. The main symptom of a Chiari malformation is a headache, especially at the back of the head or neck. This pain may be worse after sudden coughing, sneezing, or straining. Other Chiari malformation symptoms include:

• Neck pain
• Dizziness
• Trouble with balance or coordination
• Fainting
• Vomiting
• Muscle weakness
• Numbness and tingling in the hands and feet
• Hearing problems
• Sleep problems, including sleep apnea
• Blurry or double vision
• Trouble speaking or swallowing
• Ringing in the ears (tinnitus)
• Scoliosis (curving of the spine)

Symptoms of Chiari malformations in babies may look like other health problems such as, trouble feeding, may cry a lot or may not develop or grow correctly.

What Causes Chiari Malformation?

Chiari I malformation is likely the result of a mutation in a gene that happens during fetal growth and is present at birth (congenital). This most commonly happens randomly, but can be associated in families. This can lead to the lower back part of the skull (posterior fossa) to be to be smaller the normal. Sometimes, a Chiari malformation can occur in someone who was not born with the condition. This can happen due to a brain injury, a disease, a tumor, or an infection.

How is a Chiari Malformation Diagnosed?

A Chiari malformation is fairly common and is found 1 in 250 people. It is often diagnosed by accident during imaging tests done for things like injuries or headaches. Diagnostic tests may include one or more of the following:

• Magnetic resonance imaging (MRI)
• Cine phase-contrast (CINE) MRI
• Computed tomography scan (CT or CAT scan)
• Swallowing study
• Sleep Study

How is a Chiari Malformation Treated?

Treatment for Chiari malformation depends on the specific type. Regular checkups and imaging tests, such as MRIs, help you and your care team decide on the best treatment plan based on your individual needs.

Treatment options may include pain relivers and/or surgery. Medicines like nonsteroidal anti-inflammatory drugs (NSAIDs) and muscle relaxers can ease headaches and neck pain.

Surgery may be recommended after a thorough evaluation. The specific surgical procedure will depend on each patient’s symptoms, type of Chiari malformation, anatomy, and imaging results. Surgical treatment may include:

• Posterior fossa decompression (Chiari Decompression): A small section of bone is removed at the back of the skull to create space for CSF fluid to flow (suboccipital craniectomy)
• Laminectomy: The bony arch of the C1 vertebrae may be removed to create more space
• Duraplasty: The covering of the brain and spinal cord may be opened to alleviate pressure and ensure optimal flow of brain fluid. A patch will be sewn in to create further room and decompression
• Tonsil Coagulation: A small amount of current may be applied to the cerebellar tonsils to create more room
• Occipital-Cervical Fusion: Screws and rods are used to stabilize the skull and the spine to address cervical instability

Your Chiari Malformation Care Team

At OU Health, you benefit from expert care for Chiari malformations whether newly diagnosed, previously diagnosed or following previous surgery. Our dedicated Chiari specialist is committed to providing the highest quality care and treatment for individuals with this condition. Through a multidisciplinary approach, we collaborate with other OU Health specialties such as neurology, pain management, rheumatology, and genetics to ensure a thorough and comprehensive evaluation.