Seizures That Benefit From Epilepsy Surgery

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Recurrent seizures are generally well controlled with prescription anti-seizure medications. However, some people with epilepsy have seizures that do not adequately improve with medicine. Epilepsy surgery procedures have been among the treatment options for many years, and some of those who have seizure disorders have experienced significant improvement of symptoms after epilepsy surgery.

Most seizure types are at least moderately controlled with anti-seizure medication.

However, all seizure types could potentially be medication-resistant or intractable. This means that the seizures continue to occur at an unacceptable rate even when the doses of anti-seizure medications are increased, or when different medication combinations are used. Sometimes, a person with epilepsy experiences such intolerable side effects from the anti seizure medications that it is impossible to reach a dose that would adequately control the seizures. In these situations, when the epilepsy is found to be intractable and medication-resistant, surgery may be considered as an option.

Reasons Why Epilepsy May Be Treated With Surgery 

There are different types of seizures. These types are categorized based on several characteristics, such as the associated symptoms, the frequency of the seizures, the response to medication, the region in the brain where the seizure typically begins, and whether there is a known syndrome responsible for the seizures.

Some people who experience seizures may benefit from epilepsy surgery.

When the seizures are caused by tumors, certain infections and other brain abnormalities: When seizures are caused by a growth or a mass in the brain, removal of that mass is often one of the most effective ways to reduce the frequency and severity of the seizures.

Recurrent seizures may be caused by brain tumors, metastatic tumors from cancers in the body, infections, abscesses, foreign bodies, blood vessel malformations and inflammatory cysts. Depending on the location, size, and number of these types of lesions in the brain, it may or may not be feasible for you to have them safely removed.

When seizures are focal seizures: Seizures are often described as focal onset or generalized onset. Focal onset seizures begin with abnormal electrical activity in one or a few small regions of the brain. This is often discovered based on the symptoms or by EEG recordings and may or may not show corresponding abnormalities on brain imaging tests such as Brain MRI. When focal seizures are medication-resistant, epilepsy surgery is generally targeted to the main area of abnormal electrical activity in the brain to help control the seizures.

When seizures are generalized seizures: Generalized seizures, unlike focal seizures, begin with electrical activity that affects the whole brain. This can make it difficult to identify a specific brain region for epilepsy surgery. There are surgical procedures that are used to reduce the frequency and severity of medication-resistant generalized seizures.

These procedures may involve removing or cutting a region of the brain, such as the corpus callosum, that promotes the electrical connections between different areas of the brain.

When you have an epilepsy syndrome:  Your doctor may have diagnosed you with one of the epilepsy syndromes. These syndromes are conditions which have some characteristics in common, such as the type of seizure, the frequency, age at which they begin, and associated EEG or MRI abnormalities. Rasmussen syndrome, for example, is a rare seizure disorder characterized by intractable seizures that are associated with inflammation of the brain.

Stereotactic Surgery and Open Craniotomy

There are two main approaches to epilepsy surgery: stereotactic surgery and open craniotomy. Stereotactic surgery is a type of surgery that uses a wire or a tube, which is placed through a tiny hole in the skull to reach the target location in the brain. Open craniotomy is a type of surgery that involves removal (and later, replacement) of a small or large section of the skull (cranium) to effectively repair the problem.

Both methods have been used for decades, and both are considered safe in experienced hands. Your surgical team will decide on the optimal surgical approach for you based on a number of factors, such as the best way to access the target location for your type of epilepsy and the results of your pre-surgical testing.

Types of Epilepsy Surgery

There are a number of different surgical procedures for epilepsy, including the following:

Vagal nerve stimulator: A vagal nerve stimulator is a device that stimulates the vagus nerve, which is a nerve located in the neck. This electrical stimulation can reduce seizures for some people who experience intractable epilepsy.

Neurostimulator: A neurostimulator is a small device that is surgically implanted in the skull with wires that are placed on the surface and/or inside the brain. The Neurostimulator detects any abnormal electrical cerebral activity that can lead to seizures.  When those discharges are detected, this device delivers an electrical stimulation to that specific region of the brain preventing the seizures from developing.

Stereotactic laser ablation or radiosurgery: These are minimally invasive treatments that use lasers or radiation to destroy the lesion that is causing the seizures.

Corpus Callosotomy: The corpus callosum is an important bundle of nerve fibers that allows the left and right sides of the brain to communicate with each other. This is a type of epilepsy surgery that is used to prevent the spread of seizures or to reduce the severity of generalized seizures by reducing the communication between the two sides of the brain.

Multiple subpial transection: This type of involves precisely cutting a small section of the brain to prevent seizures from starting or spreading. Transection is planned in a way to minimize the risk of neurological damage.

Focal Resection: A focal resection is removal of a small section of the brain. This type of procedure is used when a specific region of the brain is found to be fundamentally responsible for the seizures, and when removal of that region is not projected to produce loss of neurological function.

Lobar resection: A lobar resection is similar to a focal (small) resection, but involves removal of a larger part of the brain. Because a lobar resection is more likely to cause loss of neurological function due to its size, focal resections are generally preferred when possible.

The Right Type of Epilepsy Surgery for You

The type of surgery that you may need depends on which type of epilepsy you have, as well as your pre-surgical testing results. Pre-surgical testing includes EEG, brain imaging tests, and functional neurological tests.

Pre Surgical Testing for Epilepsy Surgery

Your pre-surgical testing for epilepsy surgery serves two purposes: to identify the region in your brain that is most likely to be the cause of your seizures and to carefully plan your surgery to avoid new neurological deficiencies after your surgery.

EEG tests identify areas of abnormal electrical activity to localize the regions in your brain that may be most responsible for your recurrent seizures. Brain imaging tests can allow for visualization of your brain, and can locate abnormalities, such as tumors and abscesses. Functional neurological testing is more time consuming, and requires your active participation. These tests can evaluate the exact location in your brain that controls some of your actions, such as speaking or reading, to ensure that the surgical resection or ablation does not affect your abilities. 

A Word From Verywell

Epilepsy surgery is an option for some people who do not experience enough improvement with prescription anti-seizure medications. Epilepsy surgery has been around for decades, and with increased experience the procedures have been improving over the years. 

The planning for epilepsy surgery includes careful assessment of your seizures and pre-surgical testing that includes imaging tests, EEGs, and functional testing. Your team consists of specialists who have experience with managing epilepsy and with epilepsy surgery and procedures. 

Outcomes after epilepsy surgery are considered to be quite good, with few complications and with overall substantial improvement of seizures. This is in large part because not everyone with a seizure disorder is the right candidate for epilepsy surgery, and selection of the specific surgical procedures is carefully tailored to each individual.

If you are a candidate for epilepsy surgery, you can and should learn as much about your procedure as possible. This will help you so that you will know what to expect before and after surgery, as you recover from surgery, and as you adapt once you have recovered.

Source:

Rathore C, Radhakrishnan K. Concept of epilepsy surgery and presurgical evaluationEpileptic Disord. 2015 Mar;17(1):19-31; quiz 31. doi: 10.1684/epd.2014.0720.

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