The following outlines the procedures and considerations prior to epilepsy surgery and then describes the surgery, itself.
Types of Surgery
- Temporal Lobectomy is the most frequent type of surgery performed for
- Surgery is usually done for Complex Partial Seizures or secondarily
- “Extra temporal” surgery removes a part of the brain outside of the temporal lobe.
When to consider Surgery
- When three or more anti-seizure medications have not controlled your seizure activity.
- Your seizure type is Complex Partial or secondarily generalized.
- Your seizure focus (where your seizure starts) can be localized.
- The area (focus) can be safely removed.
Benefits vs. Risks with Surgery
Questions to Consider
- What are your goals for surgery?
- What are your risks for injury with seizures?
- How do your seizures affect your quality of life?
- How do you think your life would be different if your seizures were controlled?
Tests prior to Surgery
In general, testing is done to clarify your type of seizure and to localize the “seizure focus”, where they start in your brain. No one test alone gives enough information for surgical treatment; therefore, several tests are conducted.
- MRI (magnetic resonance imaging) – provides an image of your brain.
It is a painless procedure. You will lie flat on a narrow table inside the
opening of a large magnet. You will need to lie still while the
scan is completed. You will hear humming/whirring sounds.
- Baseline EEG – This is usually completed at the beginning of
your hospitalization. An EEG records the electrical activity
of the brain. A baseline, in between your seizure activity, gives clues
to the type of seizure and location.
- Video/EEG Intensive Monitoring – Your electrical brain activity,
along with a video recording of your seizure activity can usually provide a definitive diagnosis of your seizure type and is much better at localizing your seizure focus. It is important to record your brain waves before, during and after a seizure. The video picture makes the interpretation of your EEG more accurate.
- Neuropsychological Testing – A variety of tests that look at different
areas of the brain; including memory, IQ, motor and speech function.
These tests can help locate your seizure focus because sometimes the
area where the seizure starts doesn’t work as well as the rest of the brain. This is not always true; there can be just a slight difference.
Everyone has areas of the brain that are stronger or weaker than
others, but in people with seizures the weaker area usually corresponds with the seizure focus.
- SPECT Scans – In general, when a patient has a seizure, the blood
flow increases in the area of the brain where the seizure begins. And, in between seizure activity the blood flow is less.
- Ictal (Seizure) SPECT Scan – 45 seconds or less after the onset of your seizure, the nurse will inject a minute amount of a radioactive tracer (very low dose of Radioactivity) into an I.V. in your arm. This tracer marks the area where the blood flow was increased during your seizure. A scan is performed up to 6 hours after the injection to assist in identifying your seizure focus. This is a painless procedure. You will go downstairs to Nuclear Medicine for this scan. You will lie on a narrow table while a huge camera scans your head; it takes approximately 45 – 60 minutes. You will not experience any side effects from the radioactive tracer.
- Interictal SPECT Scan -The radioactive tracer will be injected when no seizure activity has occurred for several hours or more. A comparison of the two scans will be made.
- PET Scan – Similar to SPECT but this scan looks at brain metabolism or activity rather than blood flow. Like blood flow, in between seizures the seizure focus usually uses less blood sugar than the rest of the brain. This test also requires a radioactive tracer. This test is not required for everyone, and is only performed in between seizures, not during seizure activity. To prepare, you have to be NPO (nothing by mouth), including no caffeine, no sugar, and no chewing gum for four hours before the injection of the tracer. After the injection, you need to sit quietly for an hour. Otherwise the experience is basically the same as the SPECT scan.
- Wada Test – Also called an intracarotid sodium amobarbital test.
almost every patient gets this test prior to surgery. It is sometimes used to obtain more information about the location of your seizure focus; but the primary purpose is to determine if you use the left or right side of your brain for speech and language. The test also checks to see if your memory is better on one side than the other. Usually, speech and language are better on the side that doesn’t have the seizure focus. This test alone does not determine if you are a candidate for surgery, but it is important to know before surgery.
- You arrive the day before the Wada test for a check up at the clinic, and blood work. The morning of your test you should arrive at the EEG lab at 07:30AM for the application of scalp electrodes. Your Wada test will usually be from 9:00AM to around 12:00PM.
- The test is similar to a cardiac catherization except that the physicians are looking at the brain instead of the heart. A team of physicians and nurses will monitor you very closely. A very small incision is made, usually on the right side of your upper thigh, and a small catheter is inserted. You will be injected with a medine that puts one half of your brain temporarily to sleep. The physicians will do a series of tests that will look at the function of the half of your brain that is awake. Once the anesthesia wears off (approximately 25 minutes) the physicians will repeat the procedure to test the opposite half of your brain.
- Once the test is completed you will lie flat for six hours and should not bend the leg on the side of the incision. You will be allowed to turn on your side, with your leg remaining straight, after 1-2 hours. You will be transferred to a unit, usually 6 Central or 6 West, where the nursing staff will monitor you during a 6-hour period. They will assess the incision site, take your blood pressure, pulse, and respirations, check your neurological status initially every fifteen minutes, then every half-hour, and progress to every hour. Most patients are discharged to home the same day. If you live far away, you may need to spend the night in Charlottesville. You will not be discharged from the hospital until after the six hour time period.
- All your tests will be reviewed by a committee of Epileptologists,
Neurologists, neuropsychologists, and Neurosurgeons to determine if
You are a candidate for surgery.
Scalp electrodes are relatively far away from the brain. There is skin, muscle, bone and cerebral spinal fluid between the scalp electrodes and the brain, which can make localization less precise. Sometimes, in order to get the information needed to localize the seizure focus the physicians will need to surgically place electrodes inside the skull. The electrodes remain in place until a sufficient number of seizures are captured. There are different types of electrodes that can be applied. Remember this is a joint decision between you and your physician; you always have the final decision.
- There are different types of electrodes that can be applied. Electrodes on the surface of the brain – “subdurals” (occasional epidurals)
- Grids – 20-64 electrodes in a 4x4in. rectangular piece of plastic, require a larger incision
- Strips – 4-8 electrodes in a strip of plastic 2-4 in. long, require what the neurosurgeon refers to as a burr hole.
- Electrodes inserted into the brain – “depth”
- The brain itself does not feel pain.
- Prior to insertion a stereotactic frame will be placed on your head and an MRI performed to obtain a three dimensional picture of your brain to
know exactly where to place the electrodes.
- The type of electrodes and where they are placed depends on results or your earlier testing and which areas of the brain need to be looked at more closely. Once the electrodes are placed, you will be in the intensive monitoring unit to use the video and EEG to record your seizure activity. Sometimes, the physicians will do cortical mapping and this will be explained to you. Sometimes the final surgery to remove the seizure focus is done when the electrodes are removed, and sometimes at a later date.
Your length of stay will vary; each person is an individual and responds differently to surgery. Usually, patients spend 1-2 nights in the Neuro Intensive Care Unit where they are monitored very closely. Afterwards, you will be transferred to either 6 Central or 6 West to complete your stay. When the physicians are confident you are doing OK you will be discharged to home (usually 4-5 days after the operation).
After surgery you can expect to experience some headache, occasional facial swelling and bruising, difficulty opening your mouth widely, and some temporary mild visual disturbance. If the surgery occurred on your dominant language side, you may have difficulty speaking clearly at first; a few people haven’t been able to talk at all for a few days. You are also at a slightly increased risk of having a seizure right after surgery. You can usually get out of bed briefly the day after your surgery. Remember, you are an individual and may or may not experience the above symptoms. As with any surgery, you will need lots of rest and a quiet environment.
When you are discharged to home, you will still continue to need lots of rest. Do not lift anything that is heavier than 10 lbs. You will still be at risk for seizures as the brain takes one year to totally recover. You should continue to take your anti-seizure medication as prescribed by your physician. Usually you can return to work or school after six weeks. Again, everyone has a slightly different experience.
Any permanent side effects will be evident within about the first six weeks. Most of your recovery will occur within the first six weeks. One year after surgery Neuropsychological-testing will be administered. Surgery as a treatment for seizures started in the 1920’s so there is lots of information about long term outcomes.
If you have any concerns or questions, anything you do not understand, please feel free to discuss them with your nurse or physician. They will be glad to assist you in your care.