Surgery may be recommended in cases where seizures cannot be adequately controlled by medication. Doctors also generally recommend surgery if there is an identifiable brain lesion -- a damaged or dysfunctional area -- believed to cause the seizures. The most common type of surgery for epilepsy is removal of a seizure focus -- or small area of the brain where seizures originate. Other types include multiple subpial transection, corpus callosotomy, and surgery to implant a device known as a vagus nerve stimulator.
When a person's seizures cannot be adequately controlled by epilepsy medications, doctors may recommend that he or she be evaluated for epilepsy surgery.
Epilepsy surgery is performed by teams of doctors at medical centers. To decide if a person may benefit from surgery, doctors consider the type or types of seizures he or she has. They also take into account the brain region involved and how important that region is for everyday behavior.
Surgeons usually avoid operating in areas of the brain that are necessary for speech, language, hearing, or other important abilities. Doctors may perform tests such as a Wada test (administration of the drug amobarbital into the carotid artery) to find areas of the brain that control speech and memory.
They often monitor the patient intensively prior to surgery in order to pinpoint the exact location in the brain where seizures begin. They also may use implanted electrodes to record brain activity from the surface of the brain. This yields better information than an external electroencephalogram (EEG).
There are three broad categories of epilepsy that can be treated successfully with surgery. These include:
- Focal seizures
- Seizures that begin as focal seizures before spreading to the rest of the brain
- Unilateral multifocal epilepsy with infantile hemiplegia (such as Rasmussen's encephalitis).
Doctors generally recommend surgery only after patients have tried two or three different medications without success, or if there is an identifiable brain lesion -- a damaged or dysfunctional area -- believed to cause the seizures.