Epilepsy surgery is a medical procedure that involves removing the specific area of the brain responsible for causing seizures. This approach is particularly effective when seizures originate from a single, well-defined location in the brain.
Although not the first line of treatment, surgery is considered when medications fail to control seizures. The patient’s eligibility is determined through a series of detailed tests and evaluations.
Why Is Epilepsy Surgery Needed?
Epilepsy surgery is recommended for patients whose seizures cannot be controlled with medication — a condition known as medically refractory epilepsy or drug-resistant epilepsy.
Through surgery, the affected brain area is treated to reduce or completely stop seizures, often eliminating the need for lifelong medication.
What Happens When Epilepsy Is Not Controlled?
Uncontrolled epilepsy can lead to several serious health and safety risks, including:
- Depression and anxiety
- Sudden unexpected death in epilepsy (SUDEP) – a rare but serious complication
- Drowning, especially during seizures that occur while swimming or bathing
- Physical injuries from falls or convulsions
- Developmental delays in children
- Cognitive decline, including problems with memory and thinking
Types of Epilepsy Surgery
Epileptic seizures occur when abnormal brain cells trigger unusual electrical activity. The type of surgery depends on the seizure’s origin, the patient’s age, and the location of affected neurons.
1. Resective Surgery
- In this procedure, the surgeon removes a small part of the brain where seizures originate — often due to a tumor, malformation, or brain injury.
- The surgery typically targets regions that control emotion, language comprehension, and visual memory.
2. Deep Brain Stimulation (DBS)
- In DBS, a device is implanted deep within the brain to deliver mild electrical signals that regulate abnormal activity.
- The device is connected to a generator placed in the chest, and the process is guided using MRI imaging.
3. Laser Interstitial Thermal Therapy (LITT)
- A minimally invasive technique that uses laser energy to destroy abnormal brain tissue.
- Guided by MRI, this method allows the surgeon to precisely target the affected area with minimal damage to healthy brain tissue.
4. Corpus Callosotomy
- This procedure involves partially or completely disconnecting the nerve fibers (corpus callosum) that link the left and right sides of the brain.
- It is especially beneficial for children with severe or widespread abnormal brain activity.
5. Hemispherectomy
- In this extensive surgery, the outer layer of one hemisphere (the folded gray matter) of the brain is removed.
- It is often performed in children with multiple seizure sites, typically caused by congenital conditions or early brain injury.
6. Functional Hemispherectomy
- Instead of removing brain tissue, this approach disconnects the nerves between brain regions.
- It is also suitable for children, as it limits seizures while preserving healthy brain function.
Possible Risks of Epilepsy Surgery
As with any surgical procedure, there are potential risks, such as:
- Language and memory difficulties, making communication or comprehension harder
- Headaches
- Stroke
- Mood changes or depression, which can affect social and emotional well-being
How Is Abnormal Brain Activity Evaluated?
To determine the exact source of seizures, doctors perform several diagnostic tests, including:
- EEG (Electroencephalogram): Records baseline electrical activity in the brain.
- Video EEG: Monitors seizures while recording video to correlate symptoms.
- MRI (Magnetic Resonance Imaging): Provides detailed images of brain structure.
Additional advanced tests may include:
- Video EEG with invasive electrodes
- Invasive EEG monitoring
- PET (Positron Emission Tomography)
- SPECT (Single-Photon Emission Computed Tomography)
How Is Brain Function Evaluated Before Surgery?
Before proceeding with surgery, brain function is assessed to ensure critical areas are preserved. Tests include:
- Wada Test:
A medication is injected into one side of the brain to temporarily disable it, allowing doctors to assess memory and language abilities. - Functional MRI (fMRI):
Measures brain activity during reading or listening tasks to pinpoint regions responsible for speech, movement, and comprehension. - Brain Mapping:
Involves placing small electrodes on the brain’s surface to observe electrical responses while performing specific tasks — helping surgeons identify vital functional areas.