Epilepsy Talk

Epilepsy and Brain Surgery — The Basics

Since there so many different types of brain surgeries — and questions — I decided to learn about them and share my findings with you.

Surgery is most commonly done when tests show that your seizures originate in a small, well-defined area of your brain that doesn’t interfere with vital functions like speech, language or hearing.

In these types of surgeries, your doctor removes the area of the brain that’s causing the seizures.

If your seizures originate in a part of your brain that can’t be removed, your doctor may recommend a different sort of surgery in which surgeons make a series of cuts in your brain.

These cuts are designed to prevent seizures from spreading to other parts of the brain.

Although many people continue to need some medication to help prevent seizures after successful surgery, you may be able to take fewer drugs and reduce your dosages.

The type of surgery used depends on the type of seizures and the area of the brain where the seizures start. The surgical options include:

Temporal Lobectomy: The most common surgical procedure performed for epilepsy is the removal of a portion of the temporal lobe, or temporal lobectomy.

These brain structures play an important role in the majority of temporal lobe seizures involving the seizure focus, or small area of the brain where seizures originate.

The cerebrum, or largest part of your brain, is divided into four paired sections, called lobes — the frontal, parietal, occipital and temporal.

In a temporal lobe resection, brain tissue in the temporal lobe is resected, or cut away, to remove the seizure focus.

In most cases, a mere 2 inches is removed. All or part of a left or right lobe may be removed surgically.

These areas of the brain are common sites of simple and complex partial seizures, some of which may secondarily generalize.

Seizures in the temporal, parietal, frontal or occipital lobes may be treated surgically if the seizure-producing area can be safely removed without damaging vital functions. 

It is the most successful type of epilepsy surgery and over 85% of patients enjoy a marked improvement in seizure control. Most of them need less medication after surgery.

Approximately 25% of those who are seizure-free can eventually discontinue antiepileptic drugs. However, up to 15% of patients notice no improvement post-surgery.

Lesionectomy: About one quarter of patients with recurrent seizures are now discovered to have small, previously unrecognized lesions, for example; a small tumor or an abnormal blood vessel.

Lesions may be located in any of the lobes of the brain — temporal, parietal, frontal, or occipital — and they can cause frequent seizures.

A lesionectomy can be very effective in cases where the whole lesion and a small surrounding margin of brain can safely be removed.

Since surgical removal of these lesions can result in complete seizure control in many patients, the patient is considered an excellent candidate for epilepsy surgery depending on the location of the lesion and its relationship to the cortex.

Removal of the lesion along with a temporal lobectomy yields excellent results in over 80% of cases, particularly those with refractory seizures.

Corpus Callosotomy: Is the severing the network of neural connections between the right and left halves, or hemispheres, of the brain.

Primary candidates are children with severe seizures that start in one half of the brain and spread to the other side.

The initial surgery may cut the forward two-thirds of the corpus callosum, leaving the rest intact. If this does not provide sufficient seizure control, the remaining portion may be cut.

A corpus callosotomy may be performed when partial seizures secondarily generalize and it is not possible to identify a single epileptic focus or when resection of a localized focus would cause a pronounced neurological deficit.

Uncontrolled generalized seizures, especially atonic seizures (drop attacks), may also be treated with this type of surgery. The usual aim of callosotomy is to reduce seizure frequency.

However, the goals of corpus callosotomy differ from those of resective surgery, in which a seizure-free outcome is more likely and expectations are higher.

Multiple Subpial Transection (MST): This operation seeks to control seizures by cutting nerve pathways.

To put it simply, vertical connections between nerves cells are thought to be associated with normal brain function, while horizontal connections appear to help seizures spread.

Subpial Transections involve cutting the horizontal connections to prevent seizures from spreading. This relatively new procedure can limit seizing and help protect functionally important regions of the brain.

It is used when the seizure focus is located in a vital area of the brain that cannot be removed, such as the speech area.

Instead of taking out the affected tissue, the surgeon severs the parallel connections between cells in the affected area.

A series of shallow cuts (transections) in the brain tissue are cut – those that are designed to prevent seizures from spreading into other parts of the brain, leaving the person’s normal abilities intact.

This relatively new procedure can limit seizing and help protect functionally important regions of the brain.

About 70% of patients who undergo a MST have satisfactory improvement in seizure control. Particularly those with partial (focal) seizures.

Hemispherectomy and Hemispherotomy: This most radical type of epilepsy surgery removes half of the brain’s cortex, (hemisphere), or outer layer.

With a functional hemispherectomy, one hemisphere is disconnected from the rest of the brain, but only a limited area of brain tissue is removed.

This surgery generally is limited to children younger than 13 years old who have one hemisphere that is not functioning normally.

While it seems impossible that someone could function with only half a brain (the other side fills up with fluid), children manage to do so because the half that remains takes over many of the functions of the half that was removed.

In fact, children often recover very well from the procedure, and their seizures usually cease altogether. The chance of a full recovery is best in younger children.

About 85% of people who have a functional hemispherectomy will experience significant improvement in their seizures, and about 60% will become seizure-free.

Misperceptions and misunderstandings about surgery are common.

While it is vital to have an accurate picture of potential complications, it is also important to dispel unfounded fears. Similarly, it is critical to have realistic expectations.

Many patients worry that removing a portion of their brain will change their personalities or who they are, but this is very rarely the case.

For most people with uncontrolled epilepsy, the area of the brain that causes seizures is not functioning properly anyway.

Since it is not doing what it should be doing, removing it is usually safe. Furthermore, electrical activity arising in the brain’s seizure focus often impairs the functioning of other brain areas.

Yet, depending on the type of surgery, more than 60% of patients can become seizure free and 90% can enjoy a significant reduction in their seizure activity.

Many patients report that, in addition to experiencing fewer seizures, they have an improved quality of life due to reduced depression and reduced medication burden.

Of course, there are worst case scenarios, like death, which occurs in less than 1 out of 1,000 cases. Or simply, maybe the surgery won’t work. Or turn out as you had hoped and expected.

But, ultimately, brain surgery is a brave and scary decision – albeit one with calculated risks. Only you can decide whether the benefits outweigh the risks. And grab that brass ring!

Other articles of interest:

Brain Surgery – Questions to Prepare Yourself  http://epilepsytalk.com/2012/04/12/brain-surgery-questions-to-prepare-yourself/

Children’s Brain Surgery…Preparing YOUR Child… http://epilepsytalk.com/2012/04/22/preparing-your-child-for-brain-surgery/

The Trouble with AEDs  http://epilepsytalk.com/?s=the+trouble+with+AEDs

Vagus Nerve Stimulation…Is it for YOU? http://epilepsytalk.com/2011/03/13/vagus-nerve-stimulation%E2%80%A6is-it-for-you/

TNS vs. VNS – NO SURGERY!  http://epilepsytalk.com/2013/03/24/trigeminal-nerve-stimulation-a-breakthrough-technology-reducing-seizures-by-up-to-66/

The Gamma Knife — Non Invasive Surgery  http://epilepsytalk.com/2012/09/12/the-gamma-knife-non-invasive-surgery/

Laser Surgery — New Breakthrough Epilepsy Treatment! http://epilepsytalk.com/2011/07/19/breakthrough-surgery-for-those-with-epilepsy/

Responsive Neurostimulation (RNS) Shown to Reduce “Untreatable” Seizures  http://epilepsytalk.com/2013/05/05/responsive-neurostimulation-rns-shown-to-reduce-untreatable-seizures-3/

Trigeminal Nerve Stimulation — A Breakthrough Technology Reducing Seizures by Up to 66%  http://epilepsytalk.com/2013/03/24/trigeminal-nerve-stimulation-a-breakthrough-technology-reducing-seizures-by-up-to-66/

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Resources:

http://www.webmd.com/epilepsy/guide/epilepsy-surgical-treatments

http://www.mayoclinic.com/health/epilepsy/DS00342/DSECTION=treatments-and-drugs

http://www.medicinenet.com/seizure/page9.htm

http://www.ninds.nih.gov/disorders/epilepsy/epilepsy_research.htm#section2_3_3

http://emedicine.medscape.com/article/251449-overview

http://neurosurgery.mgh.harvard.edu/functional/ep-sxtre.htm

http://my.epilepsy.com/epilepsy/temporal_lobectomy

http://epilepsy.med.nyu.edu/epilepsy-surgery/surgery-treatment-options/temporal-lobe-resections

http://epilepsy.med.nyu.edu/epilepsy-surgery/surgery-treatment-options/lesionectomy

http://www.surgeryencyclopedia.com/Ce-Fi/Corpus-Callosotomy.html

http://www.epilepsyfoundation.org/aboutepilepsy/treatment/surgery/typesofsurgery.cfm

http://nyp.org/health/epilepsy-surgery.html

http://www.everydayhealth.com/epilepsy/lesionectomy-surgery.aspx

http://neurology.stanford.edu/divisions/e_26.html

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