Types of Brain Surgery for Epilepsy

Epilepsy is a neurological disease of the brain, causing abnormal brain activity, seizures, unusual sensations/behaviors and loss of awareness in some individuals. Around 50 million people are affected with epilepsy worldwide, making it one of the most commonly occurring neurological disorders across the world. It is estimated that about 70% of people affected with epilepsy can live seizure-free with appropriate diagnosis and treatment.

Generally, treatment of epilepsy begins with medications, and surgery is considered when medications are not providing satisfactory control of seizures. Epileptic surgery involves removal of abnormal portion of the brain which is responsible for causing seizures. There are different types of brain surgeries for epilepsy, and your doctor will determine the most suitable one for your specific epileptic condition.

Indications for brain surgery in epileptic patients

The best candidates for surgery include:

• People who continue to experience seizures even after trying two or more antiepileptic drugs.
• People with focal brain abnormalities that have been identified as the source point for seizures.

Different techniques of brain surgeries for epilepsy

Brain surgeries for epilepsy are either performed as open brain surgeries or minimally invasive approaches when an open procedure may seem too risky. The approach being used is determined based on the type of epilepsy and area of brain causing your seizures. The different techniques include:

Craniotomy

This technique involves removal of a removal of a part of the skull bone to expose the brain. This creates an opening in the skull bone, known as the bone flap. This procedure is done to remove brain tumors, infection, and drain accumulated blood.

Biopsy

A small hole is created in the skull to remove a small portion of defective brain tissue, which is later investigated under the microscope.

Neuroendoscopy

It is a technique in which a small endoscope (a telescope like device with a light and video camera), is used to remove tumors/defective areas of the brain, through small holes made in the skull, or through the mouth or the nose.

Types of epileptic surgeries

A number of pre-surgical tests are essential to determine your eligibility and type of brain surgery to treat your epilepsy. Doctors perform surgery when your pre-surgical tests show that your seizures are arising from small, well-defined areas of your brain and careful selection is made to avoid loss of vital functions brain area to be does not affect your vital as vision, speech, hearing, while removing the epileptic focus. The different types of brain surgeries include:

Focal resective surgery

Focal resective surgery is performed in people with seizures originating from a small part of the brain. This surgery involves removal of a small portion of the brain where seizures occur. It helps to preserve important nerve functions such as speech, sensation, movement and memory and is most commonly performed in the temporal lobe area, an area of the brain which controls emotions, visual memory and language processing.

Hemispherectomy

Hemispherectomy is a surgical procedure which is performed in people with abnormalities in one side of the brain (hemisphere). It involves removal of one side of gray matter of the brain, which is disconnected from the rest of the brain to prevent seizures from spreading. This procedure is generally considered for children experiencing seizures that arise from multiple sites in one side of the brain, usually due to a condition which is present since birth.

Corpus Callosotomy

It is a surgical procedure which involves complete/partial removal of a bundle of nerve fibres (corpus callosum), which connect the right and left sides of the brain. Corpus callosotomy differs from other procedures as it does not completely stop seizures, but the main aim is to prevent the spread of seizures from one side of the brain to the other. Preventing spread of seizures can reduce the severity of seizures. The procedure is usually considered in children with abnormal brain activity beginning on one side of the brain and spreading to the other.

Laser interstitial thermal therapy

Laser interstitial thermal therapy (LITT) is a minimally invasive procedure which uses laser to target and destroy small portions of abnormalities in the brain tissue. Laser generates high temperatures and is guided and directed towards the abnormal region, with the help of magnetic resonance imaging (MRI).

Deep brain stimulation

This procedure involves permanent placement of a device, deep inside the brain. The device is programmed to release electrical signals that disrupt abnormal brain activities inducing seizures. The generator sending electric impulses is placed in the chest and the entire procedure is guided by Neuroimaging. This procedure may decrease seizures in 40 to 50 percent of patients, approximately and is generally considered as an option in patients who cannot undergo resective surgery.

Risks associated with brain surgery

The risks of brains surgery may depend on the type of surgery and specific area of surgery, as each area of the brain controls specific functions. Your doctors will guide you in understanding the risks and strategies they use to lower your risk. Some possible risks may include:

• Problems with speech, memory and language
• Vision-related problems
• Mood changes or depression
• Stroke
• Infection
• Paralysis.

The outcomes of brain surgery for epilepsy may depend on the cause and specific areas where the seizures originate from. In some cases, people have 60-90% chance of becoming seizure free, whereas in some cases the goal is to minimize the number and severity of seizures. In all cases, thorough pre-surgical evaluation is absolutely necessary to potential risks and benefits.

Dr Dinesh Nayak

M.B.B.S, M.D (General Medicine) D.M (Neurology)

Director of Neurology and Advanced Centre for Epilepsy