Michael Smith, MD (Host): Welcome to Meaningful Medicine, a podcast by Novant Health. I'm Dr. Mike and with me is Dr. Charles Munyon, a Neurosurgeon from Novant Health. We're going to be discussing incisionless brain surgery for essential tremor. Dr. Munyon, welcome to the show.

Dr. Charles Munyon: Thank you so much for having me.

Host: Let's start with tremors, right? I think it can be a confusing issue for people. What exactly is an essential tremor and how does that impact patients' daily lives?

Dr. Charles Munyon: So essential tremor is just a term that we use to differentiate a disorder that is essentially just a tremor from tremor that can go along with other disorders. For example, Parkinson's disease is a disorder that many people are familiar with, and it has a characteristic tremor associated with it.

Now, when we are talking about tremor, what we're talking about is just a rhythmic, involuntary shaking, but that can happen in different body parts and in different phases. With essential tremor, what we mostly see is shaking in the arm and hand, and it's mostly with action. So whereas a Parkinson's patient will mostly shake when they are at rest. And their tremor will often go away when they start to move. A patient with essential tremor may not show any signs of tremor until they start to try and do things, and unfortunately, the finer the movements that they're attempting, the worse the tremor tends to become. Now, essential tremor is one of the most common movement disorders, and it becomes more common as people age.

There is a form that runs pretty strongly in families, and that does tend to show up earlier. So I will see patients in their thirties, forties, and fifties who will say yes, a lot of people in my family have a tremor, and I'm starting to notice one too. On the other hand, even patients with no family history of tremor may develop an essential tremor as they age.

In the beginning, it is usually not much more than a minor inconvenience. Now, patients who have jobs that require very steady hands, for example, patients who are in medicine or dentistry or art or law enforcement, may notice significant impacts on their work a lot earlier than other people might.

But the important thing is that the condition is unfortunately usually progressive. So as time goes by, the tremor will tend to get worse and eventually it will start to interfere with things like writing, device use and eventually even eating, drinking, dressing, hygiene tasks. And so, many people are a little bit surprised to hear that a neurosurgeon would devote a specific or significant amount of his time to treating tremor.

 It's not a brain tumor, it's not an aneurysm, it's not a life-threatening condition, but it really can have significant negative impact on quality of life. And that's what we're here to try and help with.

Host: So you mentioned maybe there's a genetic connection, but are there any other risk factors?

Dr. Charles Munyon: We really have not identified significant risk factors. People have looked at things like, for example, certain types of chemical exposure. We know there are other conditions that can lead to tremor due to injuries in the brain in different areas, but that would not be an essential tremor. That's, that's a, a different kind of tremor.

Host: Alright, so let's talk about incisionless brain surgery, right? This is what you're doing to treat these patients. What exactly is that? What's involved with that? I know a lot of people want to know, are you using some sort of imaging? Tell us just about this process.

Dr. Charles Munyon: So incisionless brain surgery is one of the treatments that we offer. And it can be particularly attractive for patients who may not be able to undergo the more traditional incision based procedures. The key here is that incisionless is not the same thing as non-invasive, and it's very important for patients to understand this is still a brain surgery.

The key is that we are trying to make a change in the circuit that is driving the tremor. And in this case we're doing that by using between 900 and a thousand high energy focused sound waves coming from all around the patient's head and meeting at a point deep inside the brain where the circuit that drives the tremor is running.

So imaging is absolutely an extremely important part of this, and in fact, the procedure is performed in an MRI scanner. Now the sound waves are carrying vibrational energy and that energy where each of the sound waves meets at that point deep inside the brain, gets deposited as heat. So we are actually heating a small area of the brain and seeing if we can make a change.

What many people don't realize, and one of the really neat parts of this process is that if you properly calibrate an MRI scanner, it can give you information not just about anatomy, but actually about temperature. So the MRI is running and it's actually about every three seconds, refreshing the temperature at the area that we're treating.

So I can see the shape of the heating and the intensity of the heating and make my adjustments appropriately. Another pretty neat thing about this is people have been doing incisionless brain surgery for tremor previously, but they've been using radiation. So instead of lots of sound waves, you have lots of gamma rays coming in and meeting at a particular point. Now, that's worked very well. The problem is gamma rays, like any form of radiation, take a long time to work. So it is very hard to know that you are in the right spot. Okay. With the ultrasound, what is great is that by changing the amount of energy that we are sending in, we can change the temperature that we achieve.

And there is a temperature range where we can stun the area of the brain that we are looking at without causing any long-term changes. I'm always happy when I have a patient who's a Star Trek fan because they'll recognize that basically what we're doing at this point is setting phasers to stun.

So, we are looking to heat that target area to a temperature that will cause a temporary change in the function of the circuit. So it'll be offline for a couple of minutes. And what we do, because with no incisions, we don't need to use any anesthesia; so because the patient is awake, we can assess what effects we're having. It lets us not only make sure that we are targeting the appropriate area in terms of tremor relief, it also lets us make sure that we're not getting heating in an area that might cause side effects. So, before we actually make any long-term changes to the brain, we can do a short-term assessment. From there we'll do a series of treatments and each time we send in the ultrasound energy, we've only got it on for about 15 to 20 seconds at a time. And so, we increase the area of lesioning a little bit more.

We bring the patient out of the scanner, we assess again, and at some point we determine, okay, we've reached the appropriate amount of treatment. We are looking for side effects, obviously. When we're happy with the treatment, we get the patient off of the MRI table, they go to the recovery area, and from there they go home.

So the total time in the facility, pre-surgical prep, treatment time, and then post-op ends up being about three, three and a half hours.

The procedure itself only requires about 45 minutes to an hour on the MRI table, so it's, it's something that we can do pretty quickly.

Host: So let me ask you, with essential tremor, is the area in the brain that's maybe causing this, is different for each patient and so there's a certain amount of you trying to isolate that main area? Is that part of the process and then optimize where you're sending those ultrasounds? Or do you already know exactly where it's at when you're going in?

Dr. Charles Munyon: Fortunately, there is a lot of uniformity. So there may be a little bit of individual variation that is related to as our skulls develop, some people will sort of have longer heads or wider heads or taller heads and as we age, and lose some brain matter, sometimes things will move in different ways to sort of fill in the space.

But generally speaking, the particular area that we're targeting is going to be the same from individual to individual.

Host: Gotcha. How, how does a patient know if this is something that's right for them? Cause you mentioned there's other options. So how does somebody know, okay, this, this sounds pretty good. Recovery time sounds pretty good. I want to give this a shot. How do they know?

Dr. Charles Munyon: I mean, the most important key is to have a long conversation with a surgeon. This isn't something to be taken lightly. Again, some people hear incisionless brain surgery and think, oh, non-invasive, risk-free. Neither of those things are true. The risk profile is very good. It can be very appropriately managed, but it is still something that patient needs to be fully aware of.

The other issue is that focused ultrasound is a true game changer for patients who cannot have incision based surgery. So patients who are, for example, too old, who have to be on chronic blood thinners, who are immunosuppressed. There are lots of reasons why somebody might not be able to undergo an incision based surgery.

And focused ultrasound is really their by far, best chance of getting meaningful tremor reduction. But for other patients, we really do have to talk about the pros and cons of the incision based approach, which is a procedure called deep brain stimulation. In that particular surgery, instead of using sound waves to create a small burn in the brain, I'm placing implantable electrodes deep inside the brain and running a pair of wires underneath the skin down to a little battery pack just like a pacemaker under the collarbone. Now that is absolutely more invasive in the sense of involving incisions and, small holes in the skull, but we're not actually ablating any tissue with this approach.

Instead, we are going to use that battery and those wires to create shaped electrical fields that change the activity of the circuit rather than just burning a hole in it.

Host: Yeah. Yeah. Wow, that sounds very futuristic.

Dr. Charles Munyon: Well, that's, that's actually been around since the nineties. Actually even before that. But, the early nineties are really when we saw widespread adoption.

Host: What do you think the future of all this is, right? So you're looking at what you can do right now for, for tremors, bringing it back to the tremor diagnosis. Right. What's the future treatment, do you see, or what excites you about some of the research you see going on using this kind of innovation at Novant Health?

Dr. Charles Munyon: When we think about tremor, right, what we think about any disorder in the brain, what we're really thinking about is circuits. Okay. Now, tremor happens to be, you asked about, you know, is one patient's brain uniform relative to another patient. That is specifically what has made this so readily adaptable to the treatment of tremor, the uniformity, and the simplicity of the circuit.

Okay. When we think about other disorders of brain function, particularly things like epilepsy, like obsessive compulsive disorder, like depression, like substance abuse, like eating disorders, okay? All of these are still circuit disorders, but the circuitry is significantly more complex, and so knowing where to intervene becomes more challenging.

 What is so incredibly exciting right now, is that imaging advances are allowing us to look not just at the anatomy of the brain, but at the actual functional connectivity of the brain. So we can actually see which areas of the brain are active and their relationship to other areas of the brain in a way that tells us how connected they are and therefore where the dominant circuits are.

We can actually then take that information and compare it to standard connectivity maps and to other patients with the same condition, so that right now there are researchers out there developing connectivity maps for those conditions that I talked about; for depression, for obsessive compulsive disorder, for substance use disorder. Okay. As we become better able to obtain and interpret those images, we will start to be able to look at individual patient's circuitry.

So that instead of relying on what we currently rely on for tremor, which is we just look, we find the appropriate landmarks and we treat based on those landmarks; we're talking about personalized approaches, whether it's focused ultrasound, or whether it's stimulation. We are looking at the ability to intervene in the circuits that are causing dysfunction in a particular patient.

Host: So you've done this on patients. What moments really stand out to you when you see the impact of this treatment firsthand?

Dr. Charles Munyon: One of the things that's really fun about focused ultrasound is that the effect is immediate, which is not frequently the case with the kinds of things that we do in medicine. And so, we see right on the treatment table. We see smiles. Sometimes we see tears. We see patients who are stunned, who will just stand there and stare at their hand and say, I can't believe it.

I can't believe it. With deep brain stimulation, we get to see some of that on the operating table, but we really don't get that same effect until it's time to turn the system on and start to program it. And even, even, so, it's still a wonderful moment when we first activate the battery, because as we are turning up the current, you can see the patient's hand and it will just sort of slowly.

Host: That's fascinating. That must be something to see.

Dr. Charles Munyon: I will tell you that we have a dedicated team. And I think, part of it is, we were very lucky to get some very high quality team members, but I think part of it is, they love seeing the effect on the aftermath. I mean, some people have said, it's maybe not quite up there with being on the obstetric ward and getting to see mothers hold their new babies for the first time, but it's not that far off.

 The sudden improvement in function, the sudden change in quality of life and outlook is just not something that you get to experience every day. And so, our nursing team, just loves being a part of that. And when I talk to patients, the feedback that I get in return is, frequently yeah, it's nice. My hand is steady. By the way. I want you to tell your nurses how wonderful they were because mm-hmm. So, so it really is great to have such a wonderful team to work with.

Host: This has been a fascinating interview for me. What an amazing topic. Thank you so much, Dr. Munyon, for coming on today.

Dr. Charles Munyon: I could talk about this for hours.

Host: I, I know I, I have many more questions too, but we gotta go. Thank you so much. I'd love to have you on. Hey, for more information, you can visit healthyheadlines.org. If you enjoyed this podcast, please share it on your social channels and explore our entire podcast library for topics of interest to you. This is Meaningful Medicine. I'm Dr. Mike. Thanks for listening.