Chiari Malformation

What is Chiari malformation?

Chiari malformation is a structural problem in the back of the head where the skull and the spine connect. It may occur when the skull is smaller than normal or shaped in an unusual way. This causes some of the brain tissue at the base of the skull to be pushed into the upper spinal canal and may block the normal flow of spinal fluid in and around the brain. In most cases, Chiari malformation is a condition a baby is born with.

Chiari malformation can range from very mild to severe, based on how much of the brain is affected. In most patients, the Chiari malformation is mild and no treatment is needed.

Chiari malformation type I is the most common type of Chiari malformation. It can be diagnosed at any age. In infants and young children, it may be found on evaluation for swallowing problems or sleep apnea. As a child gets older, Chiari may be diagnosed on evaluation for scoliosis or headaches. Most often, Chiari I malformation is an incidental finding, that is, something seen on imaging that is unrelated to the reason the imaging was performed.

Chiari malformation type II is a different type of Chiari malformation that is found exclusively in patients with myelomeningocele.

What are the symptoms of Chiari malformation?

Children who have Chiari malformation type I usually have no symptoms. If symptoms develop, they can occur at any age. Symptoms of can include:

• Headaches
• Neck pain
• Hearing or balance problems
• Dizziness
• Difficulty swallowing or speaking
• Sleep apnea
• Curvature of the spine (scoliosis)

Chiari malformation type II can cause similar symptoms

What causes Chiari malformation?

Chiari malformation most often occurs while a baby is developing during pregnancy. Most often, the cause of Chiari malformation type I is unknown. Chiari malformation type II is always associated with myelomeningocele, the risk of which is dramatically decreased with prenatal folate.

How is Chiari malformation treated?

Children with Chiari malformation type I often do not need treatment. However, evaluation by a neurosurgeon is needed to determine if treatment is warranted. Your child’s care team at Arkansas Children’s Hospital will monitor the condition with exams and MRIs.

Surgery is usually recommended for symptoms caused by the Chiari malformation or if a syrinx (fluid in the spinal cord) is present. Chiari decompression surgery is frequently performed by the pediatric neurosurgeons at Arkansas Children’s Hospital. Surgery involves removing a small amount of bone from the back of the skull and first bone in the neck (C1). Additional steps in decompression such as opening the dura (covering of the brain) are tailored to the needs of the individual patient and will be discussed with you by your neurosurgeon.