Chiari Malformation

Overview

Mayo Clinic is one of the largest centers in the world for treatment of neurological diseases, including Chiari malformation. Mayo Clinic specialists treat more than 200 patients each year for this condition. A team of experts from different medical specialties work together to find the most appropriate treatment and to ensure the best outcome for each patient. Mayo Clinic is also a leading center for research on neurological diseases.

Diagnosis

To correctly diagnose Chiari malformation, the symptoms must correlate with radiographic imaging. A careful diagnosis by experienced neurologists and neurosurgeons will reveal the differences and spare the patient an ineffective surgical procedure. Mayo Clinic has the tools and expertise to help make an accurate diagnosis. The most definitive test used to diagnose Chiari malformation is magnetic resonance imaging (MRI) of the skull. Read more about Chiari malformation diagnosis.

Treatment Options

The goal of treatment is to halt or reverse the progression of signs and symptoms. The type of treatment depends on the severity of the disorder. Mayo Clinic doctors take a conservative approach to treating Chiari malformation to spare patients unnecessary surgery that will not alleviate their symptoms. Read more about Chiari malformation treatment. options

• Treatment in Arizona
• Treatment in Florida
• Treatment in Minnesota
• Treatment of Children & Adolescents

About Chiari Malformation

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Chiari malformation is a rare abnormality at the base of the brain that results in brain tissue extending into the spinal canal. The condition may be present at birth (congenital). Medical experts divide Chiari malformation into several types, in part to reflect the degree of displacement of the brain tissue into the spinal canal. The most common are Chiari-I and Chiari-II.

In Chiari-I malformation, brain tissue (the cerebellum tonsils — two pegs of tissue which hang off the cerebellum at the base of the brain) protrudes below the opening of the base of the skull (foramen magnum). It may also include displacement of the lower part of the brain (medulla). Chiari-I malformation usually causes symptoms in young adults and is often associated with syringomyelia (a tubular, fluid-filled cavity within the spinal cord) and abnormalities in the bones of the skull and/or spine.

Chiari-II malformation involves a greater degree of brain tissue protruding into the spinal canal. In addition to the cerebellum tonsils, Chiari-II also includes the medulla and a cavity of the brain (fourth ventricle). Chiari-II malformation is almost always associated with myelomeningocele (a type of spina bifida) and hydrocephalus (excess fluid buildup within the brain), which usually are apparent at birth. Onset in adulthood is rare.

Chiari-III and Chiari-IV malformation are rare and are apparent at birth. They are more severe and are part of a larger syndrome seen in children with spina bifida. In Chiari-III, the back of the brain protrudes from an opening in the back of the skull area. It is part of a more severe set of birth defects, requiring extensive treatment. Infants with this form of Chiari malformation may have life-threatening complications.

Chiari-IV is the most severe form; the back of the brain fails to develop normally. Most infants with this malformation do not survive infancy.