Corpus Callosotomy

The corpus callosum is a band of nerve fibers found deep in the brain that connects the two halves (hemispheres) of the brain. It helps the hemispheres share information, but it also adds to the spread of seizure impulses from one side of the brain to the other.

A corpus callosotomy is an operation that cuts the corpus callosum, breaking the spread of seizures from hemisphere to hemisphere. Seizures usually do not fully stop after these steps. They continue on the side of the brain in which they started. However, the seizures usually become less severe, as they cannot spread to the opposite side of the brain.

A corpus callosotomy is sometimes called split-brain surgery. It may be done in patients with the most extreme and uncontrollable forms of epilepsy when frequent seizures affect both sides of the brain. A serious type of seizure called a drop attack, often results in sudden falls with a high risk of injury. In addition, people considered for this procedure do not experience improvement after receiving treatment with anti-seizure medicines.

Before surgery, patients will undergo a broad pre-surgery evaluation, including:

• Seizure monitoring
• Electroencephalography (EEG)
• Magnetic resonance imaging (MRI)
• Positron emission tomography (PET)

These tests help the doctor find where the seizures begin and how they spread in the brain. It also helps the doctor decide if a corpus callosotomy is a good treatment.

A corpus callosotomy requires opening the brain using a procedure called a craniotomy. (Crani refers to the skull and otomy means to cut into.) After the patient is put to sleep (general anesthesia), the surgeon makes a cut in the scalp. Next, the surgeon removes a piece of bone and pulls back a section of the dura. The dura is the tough membrane that covers the brain. This creates a window in which the surgeon inserts special instruments for disconnecting the corpus callosum. The surgeon gently separates the hemispheres to access the corpus callosum. Surgical microscopes are used to give the surgeon an enlarged view of the brain structures.

In some cases, a corpus callosotomy is done in two stages. In the first operation, the front two-thirds of the structure is cut, but the back section is preserved. This allows the hemispheres to continue sharing visual information. If this does not control the serious seizures, the remainder of the corpus callosum can be cut in a second operation.

After the corpus callosum is cut, the dura and bone are fixed back into place, and the scalp is closed using stitches or staples.

The patient generally stays in the hospital for 2 to 4 days. Most people having a corpus callosotomy will be able to return to their normal activities, including work or school, in 6 to 8 weeks after surgery. The hair over the incision will grow back and hide the surgical scar. The person will continue taking anti-seizure medication.

Corpus callosotomy is successful in stopping drop attacks in about 75% of cases. This can decrease the risk of injury and improve the person's quality of life.

The following symptoms may occur after surgery, although they generally go away on their own:

• Scalp numbness
• Nausea
• Feeling tired or depressed
• Headaches
• Difficulty speaking, remembering things or finding words

What are the risks of a corpus callosotomy?

Serious problems are uncommon with a corpus callosotomy, but there are risks, including:

• Risks associated with surgery, including infection, bleeding and allergic reaction to anesthesia
• Swelling in the brain
• Lack of awareness of one side of the body
• Loss of coordination
• Problems with speech, such as stuttering
• Increase in partial seizures (occurring on one side of the brain)
• Stroke