What Is Epilepsy Surgery?
Most people with epilepsy can control their seizures with medication. But they aren't effective for about 30% of patients. In some cases, brain surgery may be an option.
Epilepsy surgery is an operation on the brain to control seizures and improve the person's quality of life. There are two main types of epilepsy surgery:
- Surgery to remove the area of the brain producing seizures.
- Surgery to interrupt the nerve pathways through which seizure impulses spread within the brain.
Surgery is considered only if the area of the brain where the seizures start, called the seizure focus, can be clearly identified, and if the area to be removed is not responsible for any critical functions, such as language, sensation and movement. Extensive evaluation and testing are necessary to determine if surgery is appropriate.
Who Is a Candidate for Epilepsy Surgery?
Surgery may be an option for people with epilepsy whose seizures are disabling and/or are not controlled by medication, or when the side effects of medication are severe and greatly affect the person's quality of life. Patients with other serious medical problems, such as cancer or heart disease, usually are not considered for epilepsy surgery.
What Surgical Options Are Available?
Different surgical procedures are available to treat epilepsy. The type of surgery used depends on the type of seizures and the area of the brain where the seizures start. The surgical options include:
- Lobe resection: The largest part of the brain, the cerebrum, is divided into four paired sections, called lobes -- the frontal, parietal, occipital and temporal lobes. Temporal lobe epilepsy, in which the seizure focus is located within the temporal lobe, is the most common type of epilepsy in teens and adults. In a temporal lobe resection, brain tissue in the temporal lobe is resected, or cut away, to remove the seizure focus. The anterior (front) and mesial (deep middle) portions of the temporal lobe are the areas most often involved. Extratemporal resection involves removing brain tissue from areas outside of the temporal lobe.
- Lesionectomy: This is surgery to remove isolated brain lesions -- areas of injury or defect such as a tumor or malformed blood vessel -- that are responsible for seizure activity. Seizures usually stop once the lesion is removed.
- Corpus callosotomy: The corpus callosum is a band of nerve fibers connecting the two halves (hemispheres) of the brain. A corpus callosotomy is an operation in which all or part of this structure is cut, disabling communication between the hemispheres and preventing the spread of seizures from one side of the brain to the other. This procedure, sometimes called split-brain surgery, is for patients with extreme forms of uncontrollable epilepsy who have intense seizures that can lead to violent falls and potentially serious injury.
- Functional hemispherectomy: This is a variation of a hemispherectomy, a radical procedure in which one entire hemisphere, or one half of the brain, is removed. With a functional hemispherectomy, one hemisphere is disconnected from the rest of the brain, but only a limited area of brain tissue is removed. This surgery generally is limited to children younger than 13 years old who have one hemisphere that is not functioning normally.
- Multiple subpial transection (MST): This procedure is used to help control seizures that begin in areas of the brain that cannot be safely removed. The surgeon makes a series of shallow cuts (transections) in the brain tissue. These cuts interrupt the movement of seizure impulses but do not disturb normal brain activity, leaving the person's abilities intact.
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