LITT Thermal Ablation
What is thermal ablation for epilepsy?
Thermal ablation is also called laser interstitial thermal therapy or LITT procedure. It is a less invasive surgery for carefully selected people with epilepsy. It does not involve opening the bone covering the brain.
- LITT uses laser technology to deliver a set amount of energy to a specific brain region.
- The laser energy changes into thermal or heat energy. This can remove or destroy the brain cells causing the seizures (commonly called seizure focus).
- MRI (magnetic resonance imaging) is used during the procedure to monitor the heat so it targets the correct area of the brain to be "ablated" or removed.
- A computer program marks the temperature where the probe is placed. This helps protect the brain tissue around the seizure focus.
- The procedure can remove a seizure focus with pinpoint accuracy.
- There is only a small amount of discomfort after the procedure.
- People only stay in the hospital one or two days after it.
Who are candidates for thermal ablation surgery?
When seizures persist despite adequate trials of two or more seizure medicines, the next step is to see if surgery is possible. In some people, seizures are caused by a single focus. For some of these people, epilepsy can be cured with surgery by removing the focus. A surgical evaluation tries to find the seizure focus and see if it can be safely removed. Mesial temporal lobe epilepsy (MTLE) is the most common type of focal epilepsy and can be treated surgically. It accounts for 17% to 31% of all epilepsy surgeries.
- The LITT procedure has become a good option for people with MTLE when seizure medicines don't work.
- The LITT procedure can also help people who have seizures from lesions, such as a small brain malformation, a blood vessel malformation or hypothalamic hamartoma.
- Children with similar types of lesions have also been helped with the the LITT procedure.
What happens during thermal ablation surgery?
People considering thermal ablation still need a full evaluation at an epilepsy center. The testing can find out exactly where seizures start and whether that area can be safely removed. Once the area has been found, the person is scheduled for the procedure in an operating room setting. During the procedure:
- General anesthesia is still used.
- A small incision is made in the scalp, then a small hole (the size of a pencil) is made in the skull.
- An MRI is done in the operating room (or in a different room close by) to map out the exact area to be treated.
- A small (2 millimeter) tube with the laser probe is guided, using the MRI, through the small hole in the skull to the seizure focus.
- The procedure heats up and destroys the targeted area.
- A computer program checks the temperature in nearby brain areas to protect them from heat injury.
- After the procedure, the small hole in the bone and the skin incision are closed.
After the procedure, the person usually spends just a day or two in the hospital before going home. Often the person goes back to their normal activities within 3 to 7 days.
The most frequent side effect after the LITT procedure is headache Oral steroid medication is given for a few days to lessen swelling.
Systems are available in the U.S. to perform the LITT procedure.
What are the benefits of LITT over a cortical resection for epilepsy?
A cortical resection is the most common type of epilepsy surgery. This is called an "open surgery," because it involves opening the skull and removing the area of brain where seizures start.
- The operation may last a number of hours using general anesthesia.
- A piece of bone is removed from the skull temporarily.
- After the bone is removed, about 1.5 to 2 inches (4 to 6 centimeters) of the front part of the temporal lobe is removed.
- The bone is then replaced and skin incision closed.
While this procedure may sound scary, the surgery has proven very effective in controlled studies.
- Compared to people with epilepsy treated with medicine alone, surgery for MTLE leads to greater seizure freedom and improved quality of life.
- People typically stay in the hospital 3 to 5 days or more after the surgery.
- People who have this surgery on the side of the brain with language and verbal memory may also have problems remembering and naming after surgery.
LITT is a less invasive approach. The probe is placed through a small hole in the skull, and the procedure does not require opening the skull. It is offered at many epilepsy centers in the U.S. People usually go home after a day or 2 in the hospital, and the recovery is quicker.
How well does thermal ablation work for epilepsy?
A study of 234 people who had LITT at 11 U.S. epilepsy centers found that over half (58%) of people with MTLE were seizure free 2 years after the procedure. Other smaller studies have reported 53 to at least 60% of patients were free of disabling seizures (may still have auras) 1 to 2 years after the procedure. (Kang et al, Tao et al, Youngerman et al)
These results compare well to a cortical resection on the temporal lobe. While a cortical resection may be 10 to 15% more successful in some cases, it also has more side effects. The LITT procedure with less side effects can be done first. If seizures continue after the LITT procedure, an open surgery can then be done.
- LITT has shown to be a safe and effective option to open surgery for some people with MTLE.
- The procedure requires less time, needs a shorter hospital stay, and has a quicker recovery.
- Some problems with memory have been reported after LITT. However, several studies of cognitive function after LITT are better than the ones seen after open surgery. There is also less risk of injury to the area around the seizure focus.
Are there any safety concerns with thermal ablation therapy?
Reported complications are rare. They may include narrowing of a person's vision, bleeding in the brain, or nerve damage. All of these are also rarely seen with open surgery.
- People considering surgery for epilepsy should ask their epilepsy surgery team about the benefits and risks of all types of surgery.
- For selected people, resective epilepsy surgery is the best chance for a cure.
- For others, thermal ablation or LITT is the more appropriate type of procedure.
- If surgery is not an option, other treatments including dietary therapy, stimulation devices, clinical trials and lifestyle changes may improve seizure control.
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