Chiari Malformations

What Are Chiari Malformations?

Chiari malformation is a condition caused by the compression of the cerebellar tonsils, a remnant of the hindbrain that once controlled our tails, but no longer has any meaningful function.

There are four types of Chiari malformations, but Chiari I represents more than 95% of all cases.

Chiari malformations can manifest as a complicated series of seemingly unrelated symptoms:

  • Weakness
  • Numbness
  • Pain
  • Facial and eye symptoms
  • Headaches

Some patients are even misdiagnosed with fibromyalgia due to the diffuse nature of the symptoms.

In patients with a Chiari malformation, the tonsils may be enlarged, or the skull may have developed not quite big enough to contain them and the rest of the brain, and they may be forced down into the opening at the bottom of the skull (foramen magnum) with the top of the spinal cord, causing compression of the spinal cord and widespread symptoms.

What Causes Chiari Malformations?

This syndrome can be brought on in a patient previously without symptoms by an accident or injury, where the spinal cord is traumatized within the narrow confines of the anomaly, often resulting in much worse symptoms than would be expected by either the degree of the trauma or the findings elsewhere in the spinal axis. (Since this is at the edge of the cervical MRI field of view, and many times the symptoms manifest themselves in the area of the thoracic spine, this diagnosis may be overlooked).

How are Chiari Malformations Treated?

Treatment consists of decompression of the foramen magnum and often the C1 lamina, called a suboccipital craniectomy with cervical laminectomy.

Suboccipital Craniectomy

The treatment often includes expanding the space further by putting an expanding patch on the dura, called a duraplasty, and may also include shrinking the size of the tonsils so they do not exert pressure on the brain stem and spinal cord.