I. What is epilepsy surgery?
Epilepsy surgery is a type of brain surgery that is used to stop or reduce the number of seizures you have and/or their severity. Seizures are uncontrolled bursts of electrical activity between nerve cells in the brain, which may cause you to
Changes in consciousness
Uncontrolled muscles (your muscles may twitch)
Abnormal sensations
Emotional abnormalities
Abnormal behavior
The main goal of epilepsy surgery is to reduce the number of seizures and the severity of the seizures, or ideally, to be seizure-free.
Second, what are the surgical options for seizure control?
Removal (surgical excision) of the part of the brain in the area where the seizure started (epileptogenic focus).
Disconnecting nerve cell communication in the brain to stop seizures from spreading to other areas of the brain.
Using a laser to heat and kill nerve cells and tissue in the area where the seizure started.
robotic-assisted implantation of pacemaker-like devices and electrodes that send electrical signals to block or disrupt seizure activity at its source.
Third, when do people with epilepsy need surgery?
Epilepsy surgery is usually considered when
The seizures are not controlled by antiepileptic drugs. (You may hear this condition described as drug-resistant epilepsy or drug-refractory epilepsy. Technically, this means that at least two medications have been tried and do not control the seizures well.)
You cannot tolerate the side effects of antiepileptic drugs.
Dietary therapies, such as the ketogenic diet, have not helped control your seizures well.
Seizures are frequent, severe and nerve-wracking, and life-threatening accidents may occur.
Surgery may also be recommended if the seizures are caused by a non-epileptic condition, such as a brain tumor or cerebral cavernous hemangioma.
IV. What types of patients are most suitable for epilepsy surgery?
Epilepsy surgery is most successful in those who
Patients whose seizures start and stay in one area of the brain.
Patients in whom surgery can be performed safely without causing new or additional damage to memory, speech, vision, or movement.
V. What tests are needed to determine if epilepsy surgery is appropriate?
Doctors evaluate all people (children and adults) who are being considered for epilepsy surgery with a preoperative examination. The goals of the preoperative examination are to
Determine if these tests can work together to determine where in your brain the seizure is starting.
Determine if the area of brain tissue that has been determined to be the “epileptogenic focus” can be safely removed or if the “epileptogenic focus” can be safely blocked from other areas of the brain.
Determine what important neurological functions are located near the area of the brain where the seizure started.
To help predict the outcome after surgery – the probability of a reduction in the number or severity of seizures or the cessation of seizures.
There are usually two levels of preoperative testing. The first stage involves a non-invasive examination assessment. The second stage of the preoperative examination evaluates as invasive and requires surgery. Your surgical team doctor will determine which tests are appropriate for you.
1. Stage 1 tests include.
Electroencephalogram (EEG): This is the most routine test performed on all patients who have or are suspected of having epilepsy. Your epilepsy doctor places electrodes on your scalp to measure electrical activity. Your epileptologist uses an EEG to diagnose epilepsy, locate where the seizures started in your brain, and determine whether the seizures are localized or spread throughout your brain. An EEG may not record seizures in real time (some people with epilepsy do not have seizures during EEG monitoring), but abnormal brain activity can still indicate the possibility of a seizure and locate the start of a seizure in your brain.
Long-range video EEG: This is an “upgraded” version of a conventional EEG. You will need to be hospitalized for a few days while your anti-seizure medication is usually discontinued. This test captures your seizures on the EEG, while a synchronized video captures your movements during the seizure. This information helps determine where seizures start and how they affect your brain function.
Positron emission tomography (PET) scan: This scan measures brain function in all areas of the brain. It can assist in determining where seizures start, even if you are not having seizures. Epileptologists can use it in conjunction with MRI (magnetic resonance imaging), which we call PET-MRI.
Single photon emission computed tomography (SPECT): This scan can be performed when you are in the hospital for long-range video EEG monitoring. If you have a seizure during a long-range video EEG, there may be increased blood flow in the area where the seizure started. a SPECT brain scan can see the area of increased blood flow in the brain as an aid to locate where the seizure started in your brain.
Neuropsychological evaluation and functional MRI: Neuropsychological testing assesses your language skills, memory function, and other learning skills. This test is used as a baseline to measure and compare changes in relevant neuropsychological items before and after surgery. Functional MRI tests brain activity during the performance of cognitive functions such as memory or reading, which helps your neurosurgeon understand which areas of your brain control these functions.
Wada test: This test involves injecting medication into your carotid arteries (carotid arteries), one side at a time. The medication puts one hemisphere of your brain to sleep for one to five minutes while your doctor tests your speech and memory in the other hemisphere (awake). This test helps determine which side of your brain is dominant in neurological functions (language, etc.).
2. Phase II Examination
The second phase of the examination evaluation involves a procedure in which electrodes are placed on the surface of the brain or within the brain tissue, which is closer to the location of the seizure than the electrodes placed on the surface of the scalp (the examination done in the first phase).
? Electrode placement: Based on the results of the Phase I examination, your neurosurgeon places electrodes directly on the surface of your specific area of the brain. Another option (or addition) is to place wires with electrodes deep inside your brain and into predetermined areas, with each electrode recording brain activity along the full length of the wire.
Stereotactic EEG (SEEG): This test involves placing electrodes in brain tissue at different depths of your brain – in predetermined areas and in surrounding areas associated with seizures – to create a 3D view of the onset and propagation of seizure activity.
Functional brain mapping (Mapping): After your doctor has identified seizure areas, brief electrical stimulation through electrodes placed in your brain helps map out important functional brain areas. The purpose of this test is to clarify whether seizure areas and key brain function areas overlap. This ensures the safety of surgical resection and reduces the impact on neurological function after surgery.
VI. What are the specific surgical procedures for the treatment of epilepsy?
There are several types of epilepsy surgery, including.
1. Surgical resection
In a resection, the neurosurgeon removes a specific part of your brain, possibly removing brain tissue in the area where the seizure started or removing abnormal brain tissue that caused the seizure. There are several types of resections, including
Lesion resection: This procedure involves removing lesions, such as tumors, cavernous hemangiomas, and arteriovenous malformations, that can cause seizures.
Lobotomy: This procedure involves the removal of a lobe (part of the brain). Each side of the brain is divided into four lobes – the frontal lobe (front of the head), the temporal lobe (above the ear), the parietal lobe (above the temporal area) and the occipital lobe (behind the head). During a lobectomy, the neurosurgeon removes the part of the brain where the seizure begins. Temporal lobectomy is the most common type of epilepsy surgery.
Multiple lobectomy: This procedure involves removing all or parts of two or more lobes of the brain. Consider this procedure only if you have no significant function in these lobar areas.
Hemispherectomy: This procedure involves the removal or disconnection of one hemisphere of the brain. “Disconnecting” means cutting the fibers that communicate between the left and right lobes of the brain. This procedure is usually done only when the seizures are severe and uncontrollable.
2. Surgical disconnection
These procedures involve disconnecting the area of the brain that produces seizures from the remaining normal brain tissue.
Corpus callosotomy: This procedure involves disconnecting the corpus callosum. The corpus callosum is the main bundle of fibers that connects the two hemispheres of the brain. This procedure is considered when severe, frequent seizures begin on one side of the brain and spread to the other side of the brain.
Multiple subchoroidal transverse fiber dissection: This procedure involves several “low-power cautery and cortical dissection” of localized areas of brain tissue. This procedure prevents “communication” between the nerve cells of the seizure and other normal nerve cells. This procedure may be considered when the area of the brain where the seizure is occurring cannot be safely removed (overlap with a functional area of the brain).
3. Destructive surgery
This procedure involves using 3D computer imaging to focus thermal energy precisely on the target to destroy the brain tissue that is causing the seizure.
Laser interstitial thermocoagulation
This procedure is less invasive than other craniotomies. First, the neurosurgeon punches a small hole in your skull and then places a small probe under MRI guidance into the area of your brain where the seizures begin. A focused laser is aimed at the seizure site and the energy is converted to heat and destroys nerve cells in the seizure site. A computer program monitors the temperature of nearby brain tissue in real time to protect it from thermal damage. This procedure can be used if the seizure site is confined to a small area of the brain.
4. Neuromodulation (implanted device)
This procedure involves the implantation of a device to improve and control seizures and does not involve the removal of brain tissue. They include
Vagus nerve stimulation: The use of this device involves placing wires around the vagus nerve in your neck. Your vagus nerve starts in the lower area of your brain and extends down to your abdomen. A small pulse generator the size of a matchbox is implanted just below your collarbone. The pulse generator sends predetermined electrical pulses to your brain to stop any abnormal seizure bursts. This procedure is used for people who have tried two or more antiepileptic drugs but have not controlled their seizures, and for people who are not candidates for other types of surgery or for whom surgery has not worked.
Reactive neurostimulation: This procedure involves placing a device into the brain tissue or the surface of the brain tissue in the area of seizure onset. When the device monitors seizure onset, it sends an electrical pulse to terminate the seizure. Implantation of the device is approved for people with focal seizures (seizures limited to one area of the brain) that are not controlled by two or more antiepileptic drugs.
Deep brain stimulation: This procedure involves implanting electrodes into your brain and placing the stimulator device under the skin on your chest. The electrodes are placed in the exact area where the seizure starts. The stimulator device sends signals to the electrodes to block signals from nerve cells that could trigger a seizure.
VII. What happens after epilepsy surgery?
Headaches and wound pain usually occur after epilepsy surgery and usually last anywhere from a few days. You will continue to take anti-seizure medications for at least two years after surgery. These medications help reduce the chance of future seizures. As you slowly return to your normal daily activities over about four to six weeks, you will need plenty of rest. You may be able to return to work or school in about one to three months. If you are seizure-free after two years or more, your doctor may gradually reduce your dose of antiepileptic drugs and eventually stop using them. You will not need rehabilitation unless your important neurological functions are affected (speech, memory, movement).
VIII. What are the risks of epilepsy surgery?
All surgeries have risks. Typical surgical risks include
Anesthesia risks
Bleeding
Infection
Poor or delayed healing of the incision
In addition to these risks, brain surgery may also affect important neurological functions, such as memory, speech, vision and movement. These functions are located in different areas of the brain. This is why doctors perform a thorough and careful preoperative evaluation to pinpoint the “epileptogenic focus” and minimize the impact on important brain functions.
Are some types of epilepsy surgery less risky than others?
Although all surgeries have risks, in general, less invasive procedures may be less risky. In addition to this there are the following benefits.
Shorter surgery time
Less tissue damage
Shorter hospital stays
Faster recovery
Less invasive surgical options include
Laser interstitial thermotherapy
Neuromodulation, including vagus nerve stimulation, reactive neurostimulation, and deep brain stimulation
X. Are there areas of the brain or types of surgery that are considered higher risk?
Temporal lobectomy is the most common type of epilepsy surgery. However, it is also the most delicate procedure due to the more neurological function of this area of the brain. The risks of this type of surgery include.
Memory problems.
Vision problems, such as diplopia or visual field deficits.
Impact on limb function.
Speech difficulties.
Emotional problems.
Some of these problems may be temporary and will improve in time. Risks vary from person to person.
XI. How should patients consider the risks and benefits of surgery?
The goal of epilepsy surgery is to reduce the number of seizures and the severity of seizures, or ideally, the absence of seizures. The outcome of surgery varies from person to person. Even if you are not completely free of seizures after surgery, you may still benefit from
A reduction in your dose of antiepileptic medication or the number of medications you need to take, which may also reduce the side effects of the medication
A better chance of returning to work and driving.
Reduced risk of life-threatening complications, such as sudden death from unexplained epilepsy or persistent epilepsy.
Mental problems such as depression and anxiety may improve if the procedure is successful.
On the other hand, if you are already taking two or more antiepileptic drugs and your seizures are not effectively controlled, adding more antiepileptic drugs is unlikely to stop your seizures (successful in less than 10% of cases). In addition, the more medications that are tried but don’t work, the lower the chance of seizure control, which in turn can affect your social life.
12. What can I expect if I undergo epilepsy surgery?
The success of surgery depends on many factors, including
The type of seizures you have.
The frequency and severity of the seizures.
The area of the brain involved.
The type of surgery.
Your age.
Any other existing health problems you may have.
About 50% of patients who undergo preoperative epilepsy surgery may require electrodes to be inserted into their brains for further invasive EEG monitoring to determine the site of origin of the seizures. Up to 50% of patients who undergo neuromodulation may have better seizure control. 50% to 85% of patients who undergo resection or hemispherectomy may have significantly improved seizure control and, in some cases, seizures may disappear.
If you have epilepsy and have tried medication and cannot control your seizures, then surgery may be an option. There are several types of epilepsy surgery available, and the location of the seizure onset in your brain (the epileptogenic focus) plays an important role in determining which surgery is right for you.