About 1 in 3 people with epilepsy do not get good seizure control with medication. Many of these may benefit from brain surgery to remove the area causing the seizures. In carefully chosen cases, up to 80% or more may stop having seizures after surgery.
Extensive testing is needed before surgery, to answer 2 questions:
- Where in the brain do the seizures come from?
- What is the risk of new neurological problems if surgery is done?
Testing Before Surgery
Video EEG: Admission to the hospital (Saint Barnabas Medical Center) for up to a week or more. EEG wires record continuously the whole time, with a video camera and microphone. The goal is to capture several typical seizures to identify the source. Given the short period of time available, we try to make seizures happen by lowering medication and doing “activation procedures” (lack of sleep, strobe lights, deep breathing). This can also be an opportunity to make a more rapid medication change.
MRI (magnetic resonance imaging): This gives us a detailed picture of the inside of the brain, to see what might be causing the seizures. The standard MRI done most commonly does not usually show enough detail, so even if an MRI was read as normal it is worth repeating with the “epilepsy protocol.” We recommend having the MRI in the 3T scanner at the Saint Barnabas Ambulatory Care Center, as they follow the necessary detailed procedures for an epilepsy scan. Usually no injected contrast is necessary.
PET scan (Positron Emission Tomography): The PET scan gives a picture of how well different parts of the brain are functioning. Areas causing seizures usually do not work as well as normal brain, and do not light up on the scan properly. A PET scan may show an abnormality even if the brain MRI is normal.
Neuropsychological testing: This is performed by a psychologist who specializes in epilepsy testing. Testing takes several hours and is mostly “pencil and paper.” The goal is to see what the person’s strengths and weaknesses are in brain function. This information can help confirm an area is malfunctioning, and also help estimate the risk of surgery on memory or speech functions.
Intracarotid amobarbital test (“Wada” test): The Wada test (named after Dr. Juhn Wada) is to find out which side of the brain has speech function, and to see how good memory function is on each side of the brain separately. A team of radiologists, neurologist, neuropsychologist and EEG technician do the testing. A catheter (thin tube) is inserted into an artery in the groin, and moved up to the carotid artery in the neck which brings blood to one side of the brain. A short acting anesthetic is injected, shutting down one side of the brain for a few minutes. During that time, we test speech and memory. Testing takes about 1-2 hours, and you recover at the hospital for several hours before going home. This test has very small risks because it involves a procedure inside the body, so we do not do it until we are sure someone is a good candidate for epilepsy surgery.
Magnetoencephalography (MEG): This test is done occasionally to help pinpoint electrical abnormalities in the brain that do not show up well on EEG. It takes a few hours. The head sits in a large dome, and the person needs to sit still for the whole test. There are no injections and there is no danger to the testing. People with pacemakers cannot have MEG.
Patient Management Conference: Our whole team comes together to review all the test information, and come up with a treatment plan. Your doctor will go over these recommendations at the office visit.
Medical clearance: Your primary care doctor and any other specialists you see will need to check you out to be sure you are in good enough physical shape to have surgery.
Types of Surgery
Single stage surgery: A single area causing seizures is identified on testing, and is in an area that is safe to remove. Surgery is done on the day of hospital admission, and may last 3-6 hours under general anesthesia. The person stays in intensive care for 1-2 days, then finishes recovering in a regular hospital room. The average stay is 5 days.
2 stage surgery: In some cases the testing either does not clearly pinpoint the source of seizures, or it may be close to an area of critical functions. On the first stage, the surgeon places over 100 small EEG wires inside the skull, on the surface of the brain and/or deep into the brain around the suspected areas. The person then spends the next week in intensive care. Video EEG is done, connected to the wires inside the head, to better locate the seizures. This also allows us to do “cortical brain mapping”. The neurologist and neuropsychologist spend up to a day or more at the bedside doing testing. Brief electrical pulses are sent to the EEG wires on the brain, one at a time, to see what that part of the brain does. After testing is done, an MRI is done to see precisely where the EEG leads are located. On the second stage, the surgeon goes back in to remove the EEG wires, and remove the part of the brain causing seizures. Average hospital stay is 12-14 days. This testing helps us “tailor” the surgery, for increased benefit and lower neurological risk, but may slightly increase the risk of surgical problems such as infection, bleeding or blood clots.
Risks of Surgery
There are two types of risk: neurological and surgical.
Neurological risks are changes in memory, speech, movement, sensation or vision after removing a part of the brain. These risks can be accurately predicted with the pre-operative testing, and will be discussed with you by your neurologist and surgeon before surgery is scheduled.
Surgical risks are unpredictable and we try hard to prevent them. Infection and bleeding in the brain can occur rarely, and are usually treatable with medication. Blood clots in the legs can occur from lying in bed for days; we use compression devices on the legs and low doses of blood thinners to prevent this.
The risk of death from surgery is extremely low (less than 1 in 1500 people), and is usually related to other medical problems. This is very low compared to the risk of death from seizures that are not controlled with medicine, which can be as high as 1 in 100 per year. Successful epilepsy surgery has been shown to reduce the risk of epilepsy-related death.
Recovery time is individual. There is usually fatigue for a few days to a few weeks. People are often back to work and activities in about a month or sooner. 10-14 days after surgery the scalp staples are removed at our office, and there are visits with the epilepsy doctor several times over the next 6 months.
Medications are usually continued after surgery. Once there is at least a 6 month period without seizures, we may begin lowering medications gradually. We usually do not recommend stopping medication completely until at least 2 years after successful surgery. This requires careful discussion between the patient and neurologist, as there may be some risk of seizures coming back off medication. Regular EEG testing is helpful in seeing if medication can be reduced or not.
New Jersey law requires 6 months of seizure freedom to resume driving a car. You will need to get forms from the Motor Vehicle Commission for your doctor to complete.
Authored By: Eric B. Geller, MD and Werner Doyle, MD