Epilepsy surgery: A viable option

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Epilepsy surgery: A viable option

Epilepsy surgery may be the answer if you have seizures despite medication.

Not long ago, brain surgery was a last resort for the 30 percent to 40 percent of people with epilepsy who had seizures despite anti-seizure drugs. That's changed, thanks to improved imaging technology that allows doctors to more precisely locate the section of the brain involved in seizures.

Seizures that begin in the temporal lobe, the part of your brain that runs along each side of your head, are the most common type of seizure and the most difficult to suppress with drugs. Fortunately, temporal lobe seizures respond to surgical treatment more often than do other seizure types.

Location of temporal lobe

Illustration showing location of temporal lobe

The temporal lobe is located along the sides of your brain.

Epilepsy surgery: Who is it for?

To be considered for surgery, you must have tried at least two anti-seizure drugs without success. If two drugs have failed, it is highly unlikely that any other antiepileptic drug will help you. People whose seizures always start in the same area in the brain benefit most from surgery for epilepsy. Surgery is rarely considered for people whose seizures start in several areas of the brain.

Because some childhood seizures stop at puberty, doctors often hesitate to recommend surgery for children. However, a child's chance of outgrowing the seizure disorder has to be weighed against the risk of brain damage from recurrent seizures and the burden of long-term treatment with anti-seizure drugs.

In fact, children may have the most to gain from epilepsy surgery because they risk the greatest harm from epileptic seizures. Because their brains are still developing, children are more vulnerable to permanent brain damage. Seizures also interfere with children's social development.

Mapping seizures

If you're a candidate for epilepsy surgery, your pre-surgical evaluation may include:

  • Baseline electroencephalogram (EEG). In this test, electrodes are placed on the scalp to measure electrical activity produced by the brain.
  • Video EEG. A continuous EEG with video monitoring records your seizures as they occur. Because your seizure medications have to be reduced or temporarily stopped so that seizures will occur, you'll have to be admitted to the hospital for this test. Correlating the changes in your EEG with your body's movements during a seizure helps "pinpoint" the area of your brain in which your seizures are starting.
  • Magnetic resonance imaging (MRI) or computerized tomography (CT) of the head. MRI and CT scans can identify structural problems — such as lesions or scar tissue in the brain — that could be causing seizures.
  • Positron emission tomography (PET) and functional MRI. PET and functional MRI scans can monitor the brain's activity and detect abnormalities.
  • Single-photon emission computerized tomography (SPECT). The scan image varies in color depending on the amount of blood flow. Typically, blood flow is higher in the part of the brain where seizures originate. In some cases, doctors combine several types of imaging techniques to help locate the troublesome area of the brain.

Pinpointing seizure location

Images from SPECT scan

In this example, SPECT scans taken during and between seizures are compared. The difference between the scans represents areas where blood flow increased during the seizure. Once identified, that location is fitted onto an MRI image of the brain.

Types of surgery

Different types of surgeries are used for different types of epilepsy. The most common type of epilepsy surgery is the removal of the portion of the brain — usually about the size of a golf ball — that is causing the seizures. This type of surgery is highly successful for seizures that start in the temporal lobe. Up to 90 percent of those who have temporal lobe surgery either become seizure-free or have a significant reduction in the number of seizures.

If the portion of the brain that is causing seizures is too vital to remove, surgeons may make a series of cuts to help isolate that section of the brain. This prevents seizures from moving into other parts of the brain. About 70 percent of the people who have this type of surgery, called multiple subpial transection, report improvement in seizure control.

Another type of surgery, called a corpus callosotomy, severs the network of neural connections between the right and left halves (hemispheres) of the brain. This surgery is used primarily in children who have severe seizures that start in one hemisphere and spread to the other side. This can help reduce the severity of seizures.

The most radical type of epilepsy surgery removes half the brain's outer layer (cortex). It is used in children who have seizures because of damage to just one half of the brain — which occurs in a few rare conditions that are present at birth or that appear in early infancy. The chance of a full recovery is best in younger children.

Risks on both sides

All surgery, particularly brain surgery, carries risks. For example, after temporal lobe surgery, you may have memory or language problems, but these are usually temporary. Life-threatening complications, such as stroke or brain hemorrhage, occur very rarely. But keep in mind that repeated epileptic seizures also carry risks.

"Patients face risks whether they have the surgery or not," says Gregory Cascino, M.D., a neurologist at Mayo Clinic, Rochester, Minn., and division chairman of the Section of Epilepsy.

"These people can't attain their education or employment goals," Dr. Cascino says. "Then there's the risk of physical trauma, from falls or getting burned during seizures. Prolonged seizures can also injure the brain. Epilepsy can even cause sudden death. The goals of surgery are to render the patient seizure-free and allow the individual to become a participating and productive member of our society."

Last Updated: 05/17/2006
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