The Impact of Noninvasive Epilepsy Interventions

Michael Sperling, MD, director, Jefferson Comprehensive Epilepsy Center, professor of neurology, Thomas Jefferson University

Michael Sperling, MD

Although epilepsy care has improved in the last decade, its pipeline is far from depleted. And like other neurology specialties, much of that pipeline includes various types of neuromodulation and stimulation.

Among those methods which have regulatory approval are responsive neurostimulation and deep brain stimulation, which have begun to make their mark in the field. As well, laser ablation and focused ultrasound, and the use of laser interstitial thermal ablation have increased in popularity for the potential impact they may have in epilepsy treatment.

At the 2019 International Epilepsy Congress, June 22-26, in Bangkok, Thailand, NeurologyLive sat with Michael Sperling, MD, director, Jefferson Comprehensive Epilepsy Center, professor of neurology, Thomas Jefferson University, to discuss these noninvasive interventions in epilepsy care. Additionally, he shared insight into how new minimally invasive methods compare to traditional resective surgery in epilepsy, particularly by removing the need for craniotomy, thereby allowing patients to have a much shorter hospital stay and recovery time.

NeurologyLive: What's coming down the epilepsy pipeline from a therapeutic point of view?

Michael Sperling, MD: We'll have to see if it works in epilepsy, but now focused ultrasound is something that's being explored. There's a study underway to examine its efficacy—the data right now is preliminary. But, in an utterly noninvasive fashion, you can put people in an ultrasound delivery machine that focuses multiple beams of ultrasound and where they intersect is where the action takes place so to speak. You can deliver damage to a very specific targeted area of brain within a couple of millimeters and destroy that area that way, which is even better—if it works—than having to drill a hole and put a probe in. It creates damage in the brain and destroys tissue, and by multiple techniques, it actually can heat the brain. It can cause mechanical disruption; you can take focused ultrasound for that matter and disrupt the blood-brain barrier even and deliver agents directly to the brain, for example, if you had a tumor that you wanted to treat directly.

Where that will fit in epilepsy, it's hard to say. It's all it's been done preliminary in a few places in deep brain structures for tremor. The issue in epilepsy, or in the region of the hippocampus, is that bone is very nearby and dealing with the bone will be a little trickier. Cortical lesions are also adjacent to bone, but these are all technical issues I think that should probably be able to be overcome. So, again, it's something that's promising coming down the pike. We'll learn more about it.

Brain stimulation is another method. Responsive neurostimulation has been out for a few years in the US. The FDA approved deep brain stimulation more recently, that's been approved less than a year in the US, though that's been available in Europe for about 8 or 9 years. Deep brain stimulation is a method that can be used when you don't have a precise focus that you can resect or 2 foci that you could use responsive neurostimulation for. In this case, you don't even need to know where it is. Electrodes are placed in the anterior nucleus of the thalamus on both sides; attached to an external stimulator that's placed under the skin on the chest, typically on the right side; and current can then be delivered to the thalamus however doctors wish to program it.

Right now, the standard technique is similar to vagus nerve stimulation programming, where they're stimulated for 30 seconds and then off for a few minutes and then stimulated repetitively. This technique appears to diminish seizure frequency as well, and some people also have periods of time that they can go without a seizure. Perhaps 15% to 20% of people may have 3-month intervals without seizures, which is a significant improvement when you look at the baseline seizure frequency in patients in the studies.

How has the surgical approach to epilepsy been improved?

When the medicines are not proving adequate, we now are fortunate enough to have a few other options. Epilepsy surgery is a long-standing option that's been done for nearly 100 years in the US really, although it mainly became popular in the ‘50s and ‘60s in the Western Hemisphere. Surgical techniques have changed considerably, there's been a real evolution that's quite favorable in surgical techniques in the last 20 years. I've seen this happen, and it's gratifying that anesthesia has gotten much better, quite honestly, so the safety of surgery is actually significantly improved.

The surgical techniques have been improved with the introduction of intra-operative neuroimaging, as well. Surgeons now have the ability to take MRIs done preoperatively and use those in complex imaging platforms so that they can have probes in the brain and know exactly where they are. Again, it's sort of navigating around the brain, is a way of describing it. It's called neuro-navigation.

What has the effect of laser interstitial thermal ablation been?

The use of laser interstitial thermal ablation has really swept the country in the past couple of years. At Jefferson, we've been using this for about 7 years or so. The technique came out in the US about 11 or 12 years ago—I think it was approved by the FDA in 2008. This technique is a minimally invasive technique, as the surgeons would put it, so rather than having to do a craniotomy and take out a larger piece of brain with all the associated morbidity of that, now a surgeon can make a very small twist drill hole, insert a probe, and then a laser is turned on to heat the tissue around the end of the probe. In the setting of a small epileptic lesion, you can destroy that in a relatively non-invasive way.

Practically, what does that mean? Practically, it means that people come into the hospital and go home the next day. For pain relief, they use acetaminophen—they don't need narcotics. And they can go back to work a couple of days later. I always smile when I think about an older woman that we did this surgery on, and after how she said she felt fine. I asked what she did when she went home and she said, ‘Well, I went to the mall on my way home for the hospital.’ I mean, it's at that level, as opposed to 3 days in the hospital with a craniotomy. It's significant. Analgesics, people out of work for 4 to 6 weeks, so some of these minimally invasive techniques, while still invasive, are far better than we've had had available.