For most children, medication is all that is needed to control seizures. However, some children continue to have seizures even after trying two or more different medications or a combination of medications. Seizures that fail to respond to two or more anti-epileptic medications are called medically refractory seizures.
When medication fails to control seizures, surgery (an operation) may be considered to remove or disconnect the part of the brain that is generating the seizures. This is called the epileptogenic (seizure-causing) region of the brain.
With improvements in imaging technology and EEGs, it is now easier for health-care providers to define the epileptogenic areas of the brain (the parts where seizures begin). As a result, surgery has become a well-established method of treatment in carefully selected patients.
All children with epilepsy that cannot be controlled with medication should be considered for surgery. Once referred to a hospital that specializes in epilepsy surgery, the child will undergo special investigations to inform the team about the suitability of epilepsy surgery.
There appear to be some advantages to doing epilepsy surgery in children, rather than waiting for adulthood.
Children's brains are more plastic (adaptable) than adults' brains, with a greater ability to compensate and recover when portions are removed during surgery. In some children, treating seizures earlier may prevent brain damage or changes from repeated seizures and their damaging effects on cognition and development.
Early surgery for seizures may also be recommended if the cause of seizures is identified to be a brain lesion that is growing, such as a tumour.
Goals of epilepsy surgery
As with epilepsy treatment in general, the goal of epilepsy surgery is to help control the child's seizures and help them develop as normally as possible. The primary goal of surgery is to either remove or disconnect the epileptogenic region of the brain, without causing any harm to the surrounding regions, and eliminate or significantly reduce the seizures. The epileptogenic region is that area of the brain where seizures start.
Who is surgery considered for?
Surgery for epilepsy is considered when:
- a child's seizures will not improve by themselves as the child gets older
- medications have failed to control a child's seizures (often at least two individual medications separately (monotherapy) and one combination of medications (polytherapy) will have failed to control seizures)
- the seizure-causing region of the brain can be clearly identified and can be removed or disconnected with minimal risk of harming the child
With advances in knowledge and technique in both diagnostic tools and surgery, more people with epilepsy are now being considered for surgery.
Determining whether your child is a candidate for surgery
Not every child with intractable epilepsy is a good candidate for surgery. Some children may be ruled out based on their history, investigations such as brain imaging and EEG.
If your child's history and EEG suggest that surgery may be helpful, a detailed pre-surgical evaluation will be done and the results will be thoroughly analyzed to determine:
- whether your child will be helped by surgery
- the type and exact location of the operation
The pre-surgical evaluation may consist of multiple investigations, individualized for every child. These may include high resolution brain imaging to study the brain structure/function (e.g., MRI, PET scan, fMRI), investigations to study the electrical activity (EEG) or magnetic activity of the brain (MEG), detailed psychological assessment and, sometimes, genetic testing.
Preparing for surgery
In the days before the surgery, if you decide to go ahead, the surgeon will discuss the operation with you and your child. This will include the pre-operative steps, the procedure, what is involved in recovery, risks and what to expect afterwards. An anesthetist will explain the anesthetic procedure, the associated risks and any possible after-effects. Other health-care professionals may also be involved at this stage to discuss home care and ongoing issues with you and your child. You should ask any questions you have at this time.
When you agree to the surgery, you will need to give your consent by filling out a consent form.
You will need to prepare your child for the surgery by discussing and explaining the surgery to your child in a sensitive, calm and age-appropriate manner.
Full blood tests and a coagulation profile need to be done before surgery. A coagulation profile measures how quickly your child's blood clots; if it clots too slowly, your child could bleed too much during surgery. Some anti-seizure medications inhibit the blood's clotting mechanisms and need to be stopped before surgery. The team will discuss these things with you and give you instructions for tapering off your child's medication.
What happens during surgery
On the day of the surgery, your child will not be able to eat for several hours beforehand because they will be given a general anesthetic to put them to sleep during the operation.
When the surgeons and the team are ready for them, they will be given an intravenous (IV) line and taken into the operating room. You will be able to stay in the waiting room while your child is in the operating room.
A portion of the child's hair may be cut or shaved. To help prepare your child, you can ask the surgeon about this before the surgery. The first step of the surgery is called a craniotomy, in which a part of the scalp and bone will be removed and the dura membrane pulled back to expose the brain. Where the incision is made and which part of the brain is exposed depends on the area to be operated on.
There are generally three types of surgery for epilepsy:
- Surgery that removes the epileptogenic portion of the brain is called resection or resective surgery. Examples of resection are temporal lobectomy, frontal lobectomy, lesionectomy (removal of the seizure-generating focus) or more tailored brain resections.
- Surgery that disconnects a portion of the brain to prevent the spread of seizures, without removing any brain tissue, is called disconnection surgery. Examples of disconnection surgery are corpus callosotomy and hemispherectomy.
- Surgery that “burns” the seizure-generating area of the brain with the help of laser (laser-ablation).
During the operation, a special type of EEG may be done to help the surgeon and epilepsy team to finely locate and remove or disconnect only those portions of the brain causing the seizures. This type of EEG is called electrocorticography (ECoG), because it is recorded directly from the brain surface.
After the operation, the bone will be replaced and the scalp will be sutured closed.
Your child will spend a few hours in the recovery room until they awake, then spend one or two days in the intensive care unit until their condition is stable, followed by about a week at the hospital.
When does the child requires “inside brain” EEG monitoring?
Sometimes, a child is considered a good candidate for epilepsy surgery. However, the exact seizure-generating focus cannot be identified by the pre-surgical investigations. In these cases, the epilepsy team may decide to further perform “inside brain” EEG monitoring either by placing an EEG grid directly over the brain surface in the area of interest (after craniotomy) or by inserting multiple thin wire electrodes into deeper brain regions (stereotactic-EEG or sEEG) without craniotomy.
These results may help the health-care team to localize the seizure-generating focus more confidently and avoid resection of healthier brain regions. Sometimes, the results may also suggest that the child may not benefit from surgery and the health-care team can proceed with the trial of other therapies.
Rehabilitation and return to normal activity
Any hair that the surgeon may have shaved to do the surgery will grow back, and this usually covers up any scar quite well.
How quickly your child can return to school and normal activity depends on the type of surgery and its effects on your child. Most children can return to school, at least part-time, within a month after surgery, but some children may not be able to return this quickly. If the surgery affected your child's motor function, language abilities or memory, they may need rehabilitation and therapy, either while staying in the hospital or as an outpatient. Rehabilitation may include physical therapy, occupational therapy, speech therapy or other forms of therapy.
Anti-seizure medications should be continued after the surgery, usually at the same dosages. Sometimes, your child’s health-care provider may decide to add a different medication following surgery. Sometimes the medications can be stopped after a few seizure-free years.
