What is Epilepsy Surgery?

Epilepsy surgery is a treatment that can suppress or improve epilepsy in some patients whose epilepsy is not controlled with medication. One out of three patients with epilepsy suffers from drug-resistant epilepsy; that is, their seizures cannot be adequately controlled with anti-epileptic medication.

Uncontrolled seizures can injure the brain, endanger the patient's life, and lead to social and occupational exclusion that also affects the entire family environment. In addition, high-dose antiepileptic drugs, and combinations of antiepileptic drugs, can have adverse effects, further worsening the patient’s quality of life.

When a patient is evaluated for epilepsy surgery, it is within the context of comprehensive care of the patient with drug-resistant epilepsy. In the Epilepsy Unit, professionals specialized in various aspects of the disease -- neurology, neurosurgery, neuropsychology, neuroimaging... --work as a team in order to study each case individually and determine whether the patient is a candidate for surgery to improve or cure their epilepsy.

Epilepsy surgery can control seizures when it is possible to diagnose and locate the part of the brain in which the seizures originate. The objective of epilepsy surgery is to suppress the activity in the part of the brain that causes seizures, while avoiding neurological damage that would cause something worse than epilepsy itself, that is, trying to not to affect brain functions such as language, vision, movement, and memory. 

What cases is it used for?

Epilepsy surgery may be considered for patients suffering from drug-resistant (or refractory) epilepsy, that is, patients who continue to suffer seizures despite receiving correct treatment with antiseizure medications.

For some patients with drug-resistant epilepsy, surgery is an opportunity to completely control seizures or at least alleviate them significantly. However, not every patient with drug-resistant epilepsy is a candidate for epilepsy surgery.

As the purpose of epilepsy surgery is to suppress activity in the part of the brain that is causing seizures (the epileptogenic zone), it is first necessary to do a series of studies and tests to identify with certainty the area of the brain in which the seizures originate, and to identify which brain functions may be affected by an operation in that area.

An essential test in every patient suffering from epileptic seizures is a Video-EEG, in which the patient's electroencephalogram is studied before, during and after epileptic seizures. This is a fundamental tool for locating the epileptic focus. The information from the Video-EEG is compared and complemented with additional presurgical studies, especially brain imaging (such as MRI) or the evaluation of intellectual performance, among others. 

Only in very selected cases in which all this information is not enough, the Epilepsy Unit resorts to so-called invasive study techniques, in which electrodes are implanted in the brain to better define the epileptic network and any brain functions at risk. 



What is involved in the operation?

There are different technical means for suppressing the electrical activity in an epileptogenic part of the brain, and the neurosurgeon decides which is the safest and most effective technique for each individual case based on the results of the patient’s tests and recommendations of the Epilepsy Unit.

The most effective option is to remove the brain lesion or focal point where seizures originate. This surgery does not usually require shaving the head. The surgery is usually performed with the patient under general anesthesia, although in specific cases where it is necessary to verify that no essential function, such as language, is affected, it is necessary to perform the operation with the patient under local anesthesia and with light sedation.

Epilepsy surgery intended to remove an epileptogenic zone is performed with a standard craniotomy, opening both the skull and the brain membranes. The surgeon will make an incision in the scalp, and with special tools will remove a piece of the skull, referred to as a bone flap, which will be replaced at the end of the surgery.

After this, the epileptogenic area is resected (removed) with microsurgical techniques. Intraoperative monitoring with direct brain EEG recording may be necessary to increase the chances of removal of all epileptic tissue.

The surgeon will try to remove as much epileptic tissue as possible, at the same time, trying not to affect the brain functions that reside in that region of the brain. The difficulty and risks of surgery depend on the size and location of the area that is to be removed.

Although it is much less common, there are some cases of catastrophic childhood epilepsies in which the epileptic region of the brain is very extensive, and it is not advisable to remove the entire seizure-producing portion of the brain. In these situations, the option is to surgically disconnect that region to avoid impact on the rest of the brain.

Once there is no more bleeding on the surface, the membranes that cover the brain are closed and the bone fragment that was removed is replaced and fixed. Epilepsy surgeries usually last a minimum of 3 or 4 hours.

When epileptic tissue is located in a deep and hard-to-reach region of the brain, the technique of laser ablation may be used. This type of surgery is performed with the patient under general anesthesia, and consists of applying high-intensity laser light to the deep epileptogenic zone through an optical fiber that has previously been implanted into the patient using a stereotactic technique, a neurosurgical methodology that allows devices to be implanted in deep regions of the brain with very high precision and safety. The laser light causes an increase in temperature in the surrounding region that inactivates the brain tissue causing the seizures. The state of the brain and temperature are monitored at all times with magnetic resonance imaging. In these cases, the hole in the skin and skull is a few millimeters, so the patient can be discharged in one or two days after laser ablation.

Finally, in patients with drug-resistant epilepsy who cannot benefit from epilepsy surgery that involves removing, disconnection, or ablation of part of the brain, there are neurostimulation or electrical neuromodulation (deep brain stimulation) techniques that may be useful. These techniques consist of applying electrical stimulation to the nervous system (in the brain or in a cranial nerve, depending on the case). Although these techniques cannot cure epilepsy, they can reduce the number or intensity of the seizures, which can provide comfort and increase the quality of life for patients with severe cases and for whom there is currently no other therapeutic option.

Recovery and rehabilitation after epilepsy surgery

Immediately after surgery to remove or disconnect part of the brain, the patient is transferred to the Intensive Care Unit where their vital signs and condition will be closely monitored, anticipating, if necessary, the appearance of any serious postoperative complications.

Most patients can get out of bed one to two days after epilepsy surgery. They usually return home after a hospital stay of between 2 to 5 days following the surgery, and return to their normal daily activity after four to six weeks.

When the patient returns home, although they may feel more tired than usual because their sleep cycles have been affected, they will be able to handle everyday tasks on their own, such as dressing, eating, and personal hygiene.

Pain after epilepsy surgery is usually less severe than in other surgeries, and it is usually controlled well with conventional analgesics. Sometimes the doctor prescribes a mild prescription pain reliever, but most patients only need over-the-counter pain relievers after epilepsy surgery.

The staples used to close the incisions on the scalp are removed at a follow-up visit one to two weeks after surgery, depending on the surgical procedure that has been performed. The patient will be able to wash their hair five days after surgery, even if the staples have not yet been removed. 

Risks of epilepsy surgery

Complications following epilepsy surgery are rare, affecting less than 5% of patients. It should be noted that some of these complications can be serious. Serious complications, which can be life-threatening, occur in less than 1% of cases.

General complications of brain neurosurgery:

  • Fluid fistula. Cerebrospinal fluid may leak out of the surgical wound. It may be necessary to place a special drain to prevent or fix it.
  • Bleeding in the area of surgery. Sometimes a second surgery is needed to control the bleeding.
  • Infection.
  • Inflammation or thrombosis after surgery. If it is very serious, it may require special treatment. 
  • Risks related to the specific circumstances of each patient.

Within the possible adverse effects of epilepsy surgery, in addition to the general complications mentioned above, it is important to be aware that there are also potential side effects depending on the area of the brain affected by the surgery. In some cases, some functions may be temporarily or permanently altered, and further rehabilitation may be necessary. Depending on the location of the epileptogenic zone (frontal, parietal, or occipital), the complications may vary. In general, when the parietal lobe is involved, side effects would impact motor skills, and when it is the occipital lobe, vision can be affected.

To the extent that side effects are foreseeable, the Epilepsy Unit team will explain them in detail to the patient, and discuss them extensively with the patient and their family. Depending on the severity of the epilepsy, the patient may be willing to accept certain side effects in exchange for the benefit of suppressing seizure activity. In other cases, the mildness of the seizures, or the severity of the potential side effects may mean that a decision is made not to move forward with surgery and some other technique may be considered instead.  

Who are the doctors at Instituto Clavel who perform epilepsy surgery?

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