Article In Brief
Laser ablation surgery for drug-resistant epilepsy appears to be safe and effective, with just under two-thirds of patients remaining seizure free after one year. Epileptologists not involved with the study said the results are promising but called for more research on associated neuropsychological outcomes.
Laser ablation surgery for drug-resistant epilepsy appears to be safe and effective, with just under two-thirds of patients remaining seizure-free after one year, according to a multicenter retrospective study published in November in Epilepsy Research.
Moreover, the minimally invasive laser interstitial thermal therapy (LITT) resulted in an Engel 1 outcome—achieving freedom from disabling seizures at one year— for a mixed cohort that included not only patients with mesial temporal lobe epilepsy (MTLE), comprising 56.7 percent of the cohort, but also those with focal cortical dysplasia, hypothalamic hamartoma, cavernoma, heterotopias, and tuberous sclerosis.
“Our data confirms that LITT is an effective treatment for appropriately selected patients with drug-resistant epilepsy, with a good safety profile and seizure outcomes that were very good and consistent with previous research,” said lead author Patrick Landazuri, MD, associate professor of neurology at the University of Kansas Medical Center.
In LITT, a surgeon uses MRI to navigate a laser wire toward the area in the person's brain that is the source of the seizures. Once the wire is in place, heat is used to destroy the region. The surgeon then removes the wire and seals the incision with a few stitches.
“If we can offer a minimally invasive procedure for an elective surgery, we are liable to attract more patients willing to consider epilepsy surgery,” Dr. Landazuri told Neurology Today.
The prospective LAANTERN (Laser Ablation of Abnormal Neurological Tissue Using Robotic NeuroBlate System) registry is an ongoing study at 10 centers in the US designed to enroll up to 1,000 patients undergoing laser ablation in a real world, standard-of-care fashion. LAANTERN enrollment and five-year follow-up is estimated to be complete in 2027. All centers used the NeuroBlate System cleared by the US Food and Drug Administration. Surgical technique, pre-planning, and biopsy at the time of LITT were performed per standard practice at each participating institution.
Outcome measures included Engel seizure outcome classifications; safety/adverse events and hospitalization; discharge head pain scores on a scale from 0 to 10; and quality-of-life measures using standardized instruments.
In the current Epilepsy Research paper, 42 of 60 patients (64.3 percent) in the study reached Engel 1 outcome at one-year follow up. The median length of stay after the procedure was 32.7 hours. At discharge, head pain score averaged 1.4 on a scale from one to 10. Five adverse events were reported, one categorized as serious. Seizure worry and social functioning scores improved significantly in quality of life measures.
Two patients (4.8 percent) had Engel IV outcomes, reflecting no worthwhile improvements. The 10 patients with non-MTLE who had an Engel I outcome had varied etiologies, including cortical dysplasia (two), hypothalamic hamartoma (two), cavernoma (two), tuberous sclerosis (one), or seizure foci (three).
Dr. Landazuri pointed out that treating epilepsy is a multidisciplinary effort. “The general neurologist can work with epilepsy specialists at level four epilepsy centers. Those specialists can work in turn with neurosurgeons so that patients are evaluated and given appropriate options for treatment. Epilepsy specialists want to work with general neurologists to improve care for these patients.”
He pointed out that the LAANTERN study is ongoing. “We are going to have five-year outcomes to assess the durability of laser ablation effectiveness.”
Experts who reviewed the study for Neurology Today said the multicenter, prospective nature of the study, as well as the mixed cohort including patients with non-MTLE, is a step forward for research on LITT.
“Most of the current outcomes data for LITT are single-center retrospective series,” said Rebecca Fasano, MD, associate professor of neurology in the epilepsy division at Emory University. “In single-center studies, outcomes may be related to a specific surgeon's skill, technique, and experience. The prospective design, including a wide variety of patients with different types of lesions and seizure onset locations, is also a strength.”
“Most currently published data reports outcomes in patients with temporal lobe epilepsy with or without mesial temporal sclerosis,” Dr. Fasano said. “This study, which provides outcomes data in non-MTLE patients, as well, will allow epileptologists and patients to make better-informed decisions about surgical treatment.”
She added, “Many patients who would not consider traditional surgery are willing to undergo LITT, as it is minimally invasive and only requires burr holes rather than a craniotomy,” she said. “LITT is well-tolerated with minimal complications, and patients usually go home the day after surgery. This is in contrast to traditional open epilepsy surgery, in which patients have a more prolonged postoperative course.”
Barbara C. Jobst, MD, FAAN, director of the Dartmouth-Hitchcock Epilepsy Center, agreed, pointing out that the study provides real-world clinical data from a wide variety of centers with a heterogeneous population. She said LITT is frequently performed at Dartmouth for mesial temporal sclerosis and other epileptogenic lesions, with significantly shorter stays and adverse events that are less severe than open surgery.
She cited the quality-of-life data as a strength of the study. “This is important to patients and depends on more than seizure frequency,” Dr. Jobst said.
But both reviewers cited the lack of neuropsychological outcomes as a shortcoming. Dr. Jobst said data on memory following LITT has not been systematically collected and will be an important variable in determining if the procedure is superior to standard craniotomy.
Dr. Fasano agreed. “Neuropsychological outcomes are very important, as adverse cognitive outcomes significantly affect quality of life,” she said.
Beyond its track record with MTLE, are there patients for whom LITT is especially indicated or contra-indicated? Dr. Landazuri said LAANTERN data indicate that previous anterior temporal lobectomy to the LITT target or another target location was a negative predictor of Engel I or II outcomes.
Dr. Fasano told Neurology Today that in her experience, “LITT is most effective when treating lesional epilepsy, or when sEEG identifies a clear seizure onset in patients with one seizure semiology. Patients with multifocal epilepsy, generalized epilepsy, or seizure onsets in areas of eloquent cortex are not good candidates for LITT.”
She added, “I feel that the most interesting cohort is the group of patients with non-MTLE who underwent sEEG and LITT to the seizure focus. There are only 13 such patients reported here. It will be interesting to see how similar patients do over time; this outcome data is very helpful when making surgical treatment decisions for our patients.”
Dr. Landazuri emphasized that patients choosing therapy for drug-resistant epilepsy should be counseled about the risks and benefits of different surgeries and followed closely post-surgery. “At University of Kansas Medical Center, we have long-term relationships with our patients. We are invested in them having good outcomes.”
He noted that epilepsy surgery can be a difficult choice for patients, but he cited longitudinal outcome data on patients on disability from a 2015 study in Neurology showing that those who had the most successful surgeries were able to return to work. For many others, the condition is “silently” disabling.
“The vast majority of people with epilepsy are functioning well and perfectly normally between seizures—parents, young people in college. It's the unpredictability of when the seizure is going to happen [that is disabling].”
The “take-home” message for clinicians? “Epilepsy surgery is becoming less invasive and can render patients seizure free,” said Dr. Jobst. “It is important for clinicians to refer appropriate patients to epilepsy centers where they can be evaluated for LITT.”
Dr. Landazuri has received consulting fees from Monteris Medical, which sponsored the study.