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What is it?
The corpus callosum is a band of nerve fibers located deep in the brain that connects the two halves of the brain. It helps the hemispheres share information, but it also contributes 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, interrupting the spread of seizures from hemisphere to hemisphere. Seizures generally do not completely stop after this procedure (they continue on the side of the brain in which they originate). However, the seizures usually become less severe, as they cannot spread to the opposite side of the brain.
Who is a candidate?
A corpus callosotomy, sometimes called split-brain surgery, may be performed 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 the person having sudden falls with a high risk of injury. In addition, people considered for corpus callosotomy do not experience improvement after receiving treatment with anti-seizure medications.
How is it done?
A corpus callosotomy requires exposing the brain using a procedure called a craniotomy. After the patient is put to sleep with anesthesia, the surgeon makes an incision (cut) in the scalp, removes a piece of bone and pulls back a section of the dura, 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 a magnified 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.
What happens after?
The patient generally stays in the hospital for two to four days. Most people having a corpus callosotomy will be able to return to their normal activities, including work or school, in six to eight weeks after surgery. The hair over the incision will grow back and hide the surgical scar. The person will continue taking anti-seizure drugs.
How effective is it?
Corpus callosotomy is successful in stopping drop attacks in about 50% to 75% of cases. This can decrease the risk of injury and improve the person's quality of life.
What are the side effects?
The following symptoms may occur after having a corpus callosotomy, although they generally go away on their own: Scalp numbness, feeling tired or depressed., headaches, difficulty speaking, remembering things, or finding words.