Epilepsy Surgery

What is epilepsy surgery?

An epilepsy surgery is an operation to the brain which, depending on the type of surgery, may consist of:

• Removing the area of the brain that causes seizures
• Disrupting nervous pathways that seizure impulses take
• Implanting a device to treat epilepsy

Types of epilepsy surgery

There are many types of epilepsy surgery. They target different parts of the brain depending on the location of the neurons that are causing seizures.

Your doctor will also consider your age before recommending the most suitable type of epilepsy surgery to address your condition.

• Resective surgery, where a small portion of the brain is removed. Your surgeon will cut out brain tissues from the area of the brain where seizures happen. This is usually the site of a tumour, brain injury or malformation. The awake craniotomy technique is often used for resective surgery.
• Temporal lobe resection, also known as temporal lobectomy, removes part of the brain's temporal lobe. It is the most common type of epilepsy surgery.
• Deep brain stimulation involves implanting a device permanently inside your brain. This device will release electrical signals to disrupt abnormal, seizure-inducing activity. A generator used to send the electrical pulses will also be implanted in your chest.
• Corpus callosotomy removes part of the brain that connects nerves on the right and left hemispheres of your brain. This part is called the corpus callosum. This surgery helps patients with abnormal brain activity that spreads from one side of the brain to the other.
• Hemispherectomy removes one hemisphere of the cerebal cortex. This is usually done in children with severe seizures.
• Functional hemispherectomy removes the connection nerves in the corpus callosum without removing actual pieces of the brain.

Why do you need an epilepsy surgery?

Epilepsy surgery may be an option when medications do not control your seizures.

Resective surgery is only an option if:

• Your doctor can clearly identify the area of the brain where seizures start
• The area to be removed doesn't control critical functions such as language, sensation or movement

Severe epilepsy can result in complications and health risks, such as the following:

• Physical injuries during a seizure
• Drowning, if a seizure happens during a bath or a swim
• Depression and anxiety
• Developmental delays in children
• Worsening memory and cognitive ability
• Sudden death

The expected outcome of most epilepsy surgeries is to be able to control seizures with medication.

Who should not undergo epilepsy surgery?

You should not undergo epilepsy surgery if you have serious medical problems such as active cancer or heart failure.

What are the risks and complications of epilepsy surgery?

Other than the general risks of surgery, epilepsy surgery also carry the following risks:

• Infection and bleeding
• Cognitive impairment, such as:
  • Memory and speech problems
  • Loss of vision
  • Loss of ability to coordinate movement
• A return of seizures
• Depression or other mood changes
• Headaches
• Stroke

The degree of risk depends on the type of surgery and the extent of your condition. Your doctor will explain to you the specific risks of your procedure and how they plan to reduce the risk of complications.

How do you prepare for an epilepsy surgery?

Your doctor will order extensive tests before going ahead with the epilepsy surgery. These tests will help determine your eligibility for the surgery, observe the abnormal activities in your brain and identify the surgical site.

Some tests may be performed as outpatient procedures and some may require a hospital stay.

The type of tests may include:

• Baseline electroencephalogram (EEG), where electrodes are placed on your scalp to measure electrical activity.
• Video EEG, which is a continuous EEG with video monitoring to record your seizures as they occur. This test involves a hospital stay so that the team can monitor you, as you will need to stop or reduce your existing medications.
• Invasive EEG monitoring, where electrodes are surgically placed on the surface of the brain or deeper inside it. The EEG monitoring is done while you are sedated.
• Video EEG with invasive electrodes, where electrodes are surgically placed on the surface of the brain or deeper inside it. For this test, the video and EEG monitoring will be done while you are awake and staying in hospital.
• Magnetic resonance imaging (MRI), an imaging test to identify damaged cells, tumours and other abnormalities that are causing your seizures.
• Functional MRI, which identifies regions of brain activity when you are doing a specific task, such as listening or reading. This helps your doctor identify the precise locations that control certain functions.
• Wada test, where a medication is injected to put one side of your brain to sleep at a time. You will then be given a language and memory function test. This helps determine which side of your brain is dominant for your language use. The Wada test can also tell the doctor if you need to be awake during part of your surgery. This test is used if functional MRI is not suitable for you.
• Positron emission tomography (PET), which uses a special imaging device to measure brain function when you're not experiencing seizures. The images are usually able to help your doctor identify the source of your seizures.
• Single-photon emission computerised tomography (SPECT), which measures blood flow in your brain during a seizure. Blood flow is usually higher in the part of the brain where seizures occur. This test involves a hospital stay.
• Brain mapping, where small electrodes are surgically placed on the surface of the brain. You will then be asked to perform some tasks while your doctor observes your brain's electrical activity.
• Neuropsychological tests to test your language and memory function.

What can you expect in an epilepsy surgery?

Most epilepsy surgery procedures involve hospital stays for 3 – 4 nights.

Estimated duration

Epilepsy surgery can take between 3 – 6 hours.

Before the procedure

Your hair will be shaved over the section of your skull that will be removed during the operation.

You will also be administered an intravenous (IV) cannula so that fluids and anaesthesia drugs can be given to you during surgery.

During the procedure

You may be hooked up to an EEG monitor so that the team can record and monitor your brain waves during the operation.

The procedure depends on the type of epilepsy surgery being performed.

In most cases, you will be put under general anaesthesia. In resective surgery using the awake craniotomy technique, the doctor may need to wake you up for part of the operation to test your language and movement skills. In this case, you will be given local anaesthesia to help you manage the pain.

Your surgeon will create a small window in the skull (craniotomy) to access the relevant part of your brain. They will proceed to perform the planned epilepsy surgical procedure.

After the procedure

You will be moved to the intensive care unit for close monitoring on the first night, before you may be transferred to a general ward for further observation.

When you first wake up, your head will be swollen and painful. Most patients need pain killers at least for the first few days.

Care and recovery period for epilepsy surgery

You will probably be unable to return to work or school for 1 – 3 months. You should have plenty of rest in the first few weeks and then gradually increase your level of activity.

You should inform your doctor immediately if you experience:

• High fever
• Redness or swelling at the surgery site
• Blood or other fluid leaking from the surgery site
• Severe headaches
• Nausea or vomiting

You will be given medication to control your seizures. If you do not experience seizures for the next one year, your doctor may consider taking you off the drugs.

Most patients who do experience a seizure after going off medication are able to control their seizures by resuming drug treatment.