Laser Ablation for Drug Resistant Epilepsy: An Effective and Minimally Invasive Surgery

Patrick Landazuri, MD

A new multicenter study that investigated 1-year outcomes of minimally invasive surgical treatment with laser interstitial thermal therapy (LITT) found it to be a safe and effective treatment option for patients with drug resistant epilepsy (DRE), with 64% of patients free of seizures at the end of the study period. 

Additionally, the study assessed quality of life with the Quality of Life (QoL) in Epilepsy questionnaire (QOLIE-31). The median score increased by 14.1 points at 1-year follow up, driven by improvements in seizure worry and social functioning. Although this total score change was not statistically significant, it is still clinically meaningful, according to Patrick Landazuri, MD, associate professor of neurology, University of Kansas Medical Center, and colleagues. 

They examined these 1-year outcomes from patients enrolled in the multicenter, prospective LAANTERN registry (Laser Ablation of Abnormal Neurological Tissue Using Robotic NeuroBlate System; NCT02392078) specifically for epilepsy treatment. They looked at the 60 LITT procedures performed for DRE. Patients with mesial temporal lobe epilepsy/mesial temporal sclerosis (MTLE/MTS) made up the majority of procedures but other etiologies were assessed, too. 

NeurologyLive talked to Landazuri to learn more about the LITT procedure, the advantages of epilepsy surgery for patients, and how it compares to these other procedures.

NeurologyLive: Could you give an overview on how the LITT procedure compares to other epilepsy surgeries?

Patrick Landazuri, MD: LITT is also known as selective laser ablation or SLA. The way it's performed is, prior to the surgery itself, the epileptologist and the neurosurgeon both clearly identify the part of the brain that's epileptogenic. That can be done in multiple ways. Sometimes, a preoperative MRI will clearly show an epileptogenic cause. Other times it's more extensive and includes recording EEG from inside someone's brain, often with intracranial electrodes, one method being stereo encephalography, or sEEG. Once that area has been defined, whether by imaging or by electrographic findings, the patient's case is discussed at a surgical conference, which is the standard of care for all surgical centers. When the decision is made to offer LITT as a potential therapy, that's discussed with the patient. When the patient agrees, they are brought to surgery and LITT is done in an MRI scanner. The patient is positioned, and the surgeon will stereotactically plan how to insert essentially a probe inside someone's brain. The surgeon then verifies the probe positioning using the MRI. When the probe is appropriately placed, the neurosurgeon starts the ablation. If it's not, then the surgeon adjusts the location of the probe. Once it's in the position, then they fire the laser into the probe. The surgeon uses the MRI during that period to take real time thermography so that they know exactly what's been heated and so that they're not injuring tissue surrounding the intended target. Then they make sure that the brain tissue that they mean to ablate is ablated to a high enough temperature. Once that's seen on the thermography, the ablation is stopped. If they think they need to get any surrounding area that the initial ablation didn't cover, then they'll move the probe again to cover that region. When they're done the probe is removed. After that it's most typically one or two stitches and then the patient goes to recovery.

Could you outline some of the advantages of LITT over other kinds of epilepsy surgery?

The main advantage of LITT versus resection or open craniotomy is that it's a minimally invasive surgery. Inserting the probe typically requires just one Burr hole, or a 3-millimeter hole for the laser equipment that KU uses, and that's the only entrance into the head. MTLE ablation is the most common ablation surgery, but the most common brain surgery for epilepsy is an anterior temporal lobectomy (ATL). This involves an incision into the skull on the side of the head that is a significantly larger opening compared to the 3-millimeter Burr hole. An ATL is a typical surgery, but what's typical to the surgeons and to the neurologist is not typical to the patient who, hopefully, only does that once. It's a big decision for the patient, and that's the big difference. In our study, we actually captured pain scores. The average pain score was 1.4 out of 10, which is very minimal head pain score at discharge.

How do you think clinicians can mediate these sometimes-disproportionate fears about epilepsy surgery?

One of the main challenges in epilepsy care is the misperception of the efficacy of seizure medicines after a certain time point. So, to be clear, medicines are a very effective treatment for epilepsy — nearly 70% of people will be seizure free on medications. The challenge is that's most typically within the first three medicines that they try. After a third failed medicine, less than 1% of people are seizure free on a long-term basis with medicines alone. So, I think it has to do with the early recognition, and appropriate referral to centers that are able to discuss surgical therapy and evaluate people that would benefit from surgery. Once a patient is at one of those centers, patients can know that our study saw 97% of patients discharged to home with our median length of stay being 32.7 hours. Coupled with the low head pain score on discharge, these findings continue to suggest LITT as a form of epilepsy surgery is a safe and well tolerated procedure.

Transcript edited for clarity. NeurologyLive has previously written about Landazuri and colleagues’ investigation, which you can read more about by clicking here.

REFERENCE

Landazuri P, Shih J, Leuthardt E, et. al. A prospective multicenter study of laser ablation for drug resistant epilepsy – One year outcomes. Epilepsy Res. 2020; 167. doi: 10.1016/j.eplepsyres.2020.106473