13 Terms Explaining How Laser Ablation Stops Seizures


If you or a loved one has been living with uncontrollable seizures, your doctor may mention a treatment option called “laser ablation.”

Dr. Davis
Kathryn Davis, MD, MTR

“It’s like giving patients a choice between open or laparoscopic surgery,” says Kathryn Davis, MD, MTR, neurologist and medical director of the Epilepsy Monitoring Unit at the Penn Epilepsy Center. “People have a similar response. Because it’s much less invasive, it’s more appealing to patients.”

Related Terms

Here are 13 terms you might hear as you discuss laser ablation with your medical team. Understanding these terms can help you decide whether laser ablation is the right next step for you.

Ablate or ablation

Ablation literally means “the surgical removal of body tissue.” In neurosurgery, that usually means resecting, or cutting out, the part of the brain that’s prompting the seizures. But with laser ablation, the technique is similar to burning the brain tissue instead of cutting it. The procedure requires tiny incisions that allow the laser beam to target the brain tissue.


Whenever you see the suffix “omy,” it means that a body part or tissue is being surgically removed. A craniotomy means the surgeon is removing a chunk of the cranium, or skull bone, to access the brain.

Laser ablation may allow patients to skip a craniotomy.


This is what happens to laser-ablated brain tissue. “You burn it. It liquefies. It’s gone,” explains Dr. Davis. “And it’s not going to regenerate.”


The clinical teams that handle seizures at Penn Epilepsy Center include neurologists. These are doctors who specialize in conditions of the brain and nervous system—everything from memory to movement disorders.

An epileptologist is also a neurologist, but with a particular focus on epilepsy and other seizure-related disorders. In addition to treating patients, epileptologists, like Dr. Davis, may also lead clinical trials to test new medications or procedures to treat epilepsy.

“Any patient considering laser ablation needs to discuss it with an epileptologist and a neurosurgeon,” advises Dr. Davis.


The US Food and Drug Administration (FDA) requires that medical devices, and the claims the manufacturers make, go through rigorous evaluations to make sure they’re safe for patients and effective for certain conditions.

Hippocampal sclerosis

The hippocampus is a structure in the temporal lobe. It is behind your eyes and almost between your ears.

The hippocampus is responsible for nearly 80% of temporal lobe seizures, reports the Epilepsy Foundation.

“The best patients for laser ablation are the ones who have clear hippocampal sclerosis in brain MRI,” says Dr. Davis. That means an MRI clearly shows hardening of the tissue in this area of the brain.

Intractable epilepsy

Intractable, or refractory, means your seizures have not been successfully controlled with medications. If medications haven’t worked,laser ablation may be a possible next step.


A laser is a very hot, high-energy beam of light. The laser used during the laser ablation procedure is precisely aimed at the brain tissue causing the seizure. The beam is only about the width of a pencil tip, which means it’s very unlikely to hit the healthy surrounding brain tissue.


Magnetic resonance image (MRI) machines have long been used to take images of the brain. During laser ablation, the patient is put in an MRI machine. The surgeon uses the images to see exactly where the laser beam is being directed.

Minimally invasive

Even though lasers are removing the brain tissue, “this is still brain surgery,” cautions Dr. Davis. “You are removing part of the brain.”

However, minimally invasive means your skull is not surgically opened to access the brain. With laser ablation, a 3.2 millimeter incision is made in the skull.

The benefits of the minimally invasive approach are that:

  • Healthy brain tissue can stay intact instead of being removed to get to the area causing the seizures.
  • Patients can have less hair removed.
  • The procedure doesn’t require as many stitches.
  • The recovery time is quicker than traditional brain surgery.

“Most patients can go home the next day,” Dr. Davis says.


If you’ve ever played darts, you know that the dart doesn’t bounce all over the board. It lands on a tiny dot, hopefully the bull’s-eye. Stereotactic procedures work similarly.

When you hear the word “stereotactic,” think of words like pinpoint or target.

Temporal Lobe

“The most common type of adult onset epilepsy is temporal lobe epilepsy,” says Dr. Davis, “meaning their seizures begin in the temporal lobe of the brain. These patients are often good candidates for laser ablation.”


This is the commercial name for the laser ablation system used at Penn Medicine. More than 1,000 Visualase procedures had been performed on patients nationwide since it gained FDA approval for neurosurgery in 2007.

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