Yale School of Medicine neurosurgeon, Dr. Charles Matouk, MD talks about a new procedure to treat normal pressure hydrocephalus.
Interview conducted by Ivanhoe Broadcast News in 2022.
What is normal pressure hydrocephalus?
MATOUK: So it’s a great question. Normal pressure hydrocephalus is a type of neurodegenerative disease. And clinically, people come to attention by the fact that they have gait instability. They have urinary urgency or even have urinary accidents and often a mild dementia. And that can present us forgetfulness. Not really in terms of things that have occurred in the past, but you’re working memory day to day, where you left your keys or situational awareness. And when you have the constellation of those three different things, and appropriate imaging and response to what we call provocative testing, we give you the diagnosis of normal pressure hydrocephalus, which is sometimes referred to as NPH for short.
For friends and family, when they’re watching a loved one start to forget things, is it normal for them to assume and foster that that’s the start of dementia? And how is that different from what we are talking about here?
MATOUK: It’s a great question and I think there’s not enough education around this fact, which is that NPH is a type of dementia. And what makes it different from the common types of dementia, like Alzheimer’s disease, or what you might just refer to as getting old, is that there’s a surgical treatment that can really make things significantly better or at a minimum, slow the progression of the disease. And what’s unfortunate about the condition is that very often it’ll go undiagnosed for many years. The wrong diagnosis will be attached to patients with this condition. And if years go by and a person deteriorates significantly, the ability to bring them back from that to see improvement, I think very much goes down. And so, I think it’s important for the public to be aware that if a loved one is suffering from memory problems and they’re older, if they also have trouble with gait stability, meaning that they lose their balance, especially if they’re taking a turn or walking downstairs, or walking on an incline. And if they’re beginning to wake up in the middle of the night because they have to go to the bathroom, or if they go to a restaurant, the first thing they want to know is where the bathroom is because of they have to go, they have to go right now or maybe even start to have some accidents. That clinical constellation of those three things, the dementia plus the gait instability and urinary problems, should at least trigger the thought of NPH. And then there’s a series of appropriate investigations that can take place so that you’re not missing an opportunity to help.
How do doctors diagnose NPH?
MATOUK: So if somebody comes to our attention with that clinical triad, the first thing that we’ll do is we’ll order a CT scan or an MRI. And MRI tends to be a little bit more helpful for this particular condition. But what we’re looking for, is that the fluid-filled spaces of the brain, which we call ventricles, are disproportionately enlarged compared to what they should be. So the fluid-filled center of the brain which houses the water, the ventricles look too big. And that in the appropriate clinical context in older patient that’s presenting with early dementia, gait instability of the urinary problems, should heighten the suspicion for the condition. And then a confirmatory test would be taking fluid off your back, which is the same as taking fluid off your brain because they’re both connected in what’s known as a lumbar tap or a large volume lumbar puncture or a tap test, sometimes people call them. And if you show improvement, especially in terms of your ability to walk your gate, then that will sense the diagnosis. So that’s the process for making a diagnosis of NPH.
What’s happening that’s causing NPH?
MATOUK: The truth is that we don’t know what causes NPH. We know that it occurs much more commonly in older people. So over the age of 75 in particular. And we know that it can be very disruptive and impair people’s quality of life, especially the time when they’re hoping, after a lifetime of work to maybe enjoy life the most, when they’re now in retirement. But the truth is that we don’t know. The analogy that I use, which is partially incorrect, but I think it helps people to understand, is that we all have in the center of our brains, a little factory that makes water. And you can think of it like a drippy faucet. So we all have that. And that faucet is drip, drip, drip dripping. And we don’t have very many things that can make it go faster or turn it off. So the rate of fluid production, like a drippy faucet is constant. What happens as we get older is that our cells die, including our brain cells. And as the brain cells die, they produce a sludge. And what the sludge does, is, it bangs up or it partially occludes the pipes that allow the fluid to get out of the brain. And because the fluid is always made at a constant rate, the amount of fluid in our head is by enlarge, determined by how good our pipes are to get water out. And so as brain cells die and produce the sludge that makes the pipes not work as well, the water backs up in a sense and that’s what gives us the symptoms. And the treatment then is to relieve the pressure, to try to get some water out of the head. What we do is create a bypass. So we create an alternate way, an alternate set of pipes, one that are built artificially with surgery to get the fluid out of our heads.
So once you get rid of that fluid, can the patient return to normal? Unlike when you have dementia or Alzheimer’s where there’s damage, you can’t get them back. Do you get some of the function back?
MATOUK: You can the thing that improves the most and the conversations that we have in clinic are when you’re deciding to treat somebody is, are the symptoms so disabling that they’re beginning to interfere with your quality of life. So that could be something as simple as taking walks with your family or gardening, or perhaps stay in your home with help or without help. And if your symptoms have risen to the occasion, then we have a discussion about whether or not the improvement that we’ve seen with the tap test or a lumbar drain is another test that we sometimes do. But both- both involve removing fluid from your back. If we see improvements, then we have a discussion about whether or not the improvements were sufficient to justify the risks of surgery. So with this amount of improvement, be impactful for you in your life. Will it improve the quality of your life sufficiently to justify the risks of surgery? And what we focus on primarily is gait. What the shunt is very good at getting better is your gait stability and your ability to walk around independently. So I don’t think many people go back to normal, but many people that have improvement with a tap test, for example, will realize significant improvement in their gait that they find meaningful. The improvement in dementia, so the cognitive problems are less pronounced as are the problems in urine. There’s always a patient that everyone knows, the one in 20, let’s say that has a miraculous improvement. But that type of miraculous improvement can be guaranteed for all, and I would say is actually relatively rare. Everyone will see improvement, but not everyone will have a home run resolved.
Can you talk about eShunt?
MATOUK: Yeah, sure. To put the eShunt context when we’re doing shunt surgery, which basically involves making several cuts on the scalp, drilling a hole in your skull, and then passing a stylet or a long metal tube through the brain to get to that fluid-filled center. And then, we place a plastic tubing that goes from that fluid cell center- fluid-filled center over our skull but under our skin and we can tunnel it behind the ear, then over our collarbone and then we typically put it in- in the abdomen. We can put it on the chest wall. Sometimes we can float into the vein which goes down into the heart and the Mac- abandoned and Mac that goes to the heart. That sounds a lot and it can be for older patients. It’s a general anesthetic. Patients are put to sleep for the procedure. The surgery takes about 45 minutes to an hour. When we looked at our own patients and patients across the country in large databases and ask the question, how many patients come back into the hospital within the first 30 days after being discharged after surgery? We were surprised that it’s about 20 percent. And the reasons are is that the shunt either gets infected or the shunt tubing gets blocked or kinked for whatever reason, or they develop a serious syndrome which is called overshunting. It’s basically your brain can’t handle how much fluid is being taken off and your brain collapses and get sunken down away from your skull. So it sinks and it’s almost like it’s deflated, which can be a serious problem and requires more surgery and those types of things often shunt removal. And so even though many patients will significantly improve after a shunt and it produces a meaningful improvement in their quality of life, there’s also a significant number of people that have a complication. And when you’re older and frail, those complications can spiral quickly. And so we’ve always known that the decision to embark, I’m putting in a shunt in this population even though we think it might be helpful, we have to use a little bit of common sense and make sure patients are informed that shunt surgery is not perfect. And in fact, has a relatively high complication rate compared to many other procedures that we do. Because of that, there’s been an interest to seeing whether or not there’s alternative, more minimally invasive techniques that can substitute or replace, a shunt that’s easier for a patient. That may be theoretically has less complications than the shunt surgery itself that we’re all doing today. And there’s a group of doctors, neurosurgeons at Tufts University in Boston that I think about 10 years ago now they came up with a concept where you can create a miniature shunt from working within the veins in your neck. So you can access the veins in your neck like the cardiologists do when they do a catheter- a heart cath procedure. Those interventional procedures where they either do a diagnostic angiogram with the blood vessels of your heart or they put a stent in because someone’s having a heart attack or about to have a heart attack. You can navigate instead of through the arteries, which is what those procedures are but rather through the veins. And the veins will go all the way up to the base of your skull. And you can work inside the vein. So inside your blood vessels through a small puncture hole on your leg and essentially create a connection, a shunt between a pocket of fluid at the base of the brain and your bloodstream. And see you’ve now replace this hole, drilling a hole on your head and a big lung shunt tubing that extends from the top of your head into your belly with really something as big as a fingernail filing that connects this pocket of fluid at the base of your brain into the- into the vein, the internal jugular vein in your- in your neck. And that in fact replaces the shunt, which is incredible. And you don’t have to drill a hole in your head and you don’t have to have the lung tubing. There’s not much to get infected, very unlikely to produce in theory, and over shunting syndrome, which we talked about. And so there’s a lot of theoretical appeal to this particular device and procedure. The first eShunts have been placed now in Buenos Aires in Argentina. And we were fortunate enough working with the docs in Boston to be the first group to implant the eShunt in the United States. And so far so good. It’s a clinical research trial. And so this is what’s called a safety in feasibility study, which is to establish the safety of the procedure with the food and drug administration before moving on to what’s called a pivotal study, where we determine whether or not the procedure is effective. But there’s a lot of enthusiasm around the device and so far, so good.
When the fluid is draining, you said either through the heart or into the abdomen, is it then passed through the system and out of the body?
MATOUK: It is exactly. All the fluid that’s anywhere in our body is essentially absorbed into your bloodstream and then we eventually urinated out. So as long as you get it into a compartment that somehow connected to the bloodstream indirectly or directly in this case, directly it will find its way out of the body.
The patient in the trial first of all, how is he or she doing?
MATOUK: So far, so good.
Why was this particular patient in a matter of risk versus benefit, really he or she could have benefited from reducing that pressure. Or maybe it was too old or too sick to do a regular shunt?
MATOUK: It’s an interesting thing. I’m involved with a lot of clinical trials. We do a lot of clinical trials at Yale. Some we lead, some where we participate in, and the reasons why people choose to participate in clinical trials is varied. I have to say from a patient perspective, there’s been a tremendous willingness to participate in the study. So whereas I think for many studies, once we get past there’s a dialogue that has to occur about these are the risks, these are the benefits. We’re not certain what they are. This hasn’t been done before. So there’s an unknown factor. But I think that many patients are so apprehensive about the traditional surgery, about if- its invasiveness about the risk of infection. Many of these folks have had surgeries and infections for other things in the past and they remember what that’s like. That they’re very enthusiastic to try something new. Even though there’s an unknown about like right now we don’t even know if it’s safe officially. Now we go through extraordinary measures, I would say to make sure that we’re picking folks that we believe are going to be super safe to undergo the procedure as we embark on these first 10 patients. But yeah, I’ve been very surprised by how eager patients and families are to participate in this particular study. That’s certainly not the case, I would say, in a majority of the studies that we run.
What would your next steps be?
MATOUK: So the study is being run by the company that developed the eShunt, which is called CereVasc. There’s three centers and- that are going to be part of this initial 10-patient trial. We happen to be the first out of the gate. But after the first 10 patients are completed and the shunts implanted and their follow-up completed, that data then has to be vetted by the Food and Drug Administration and they make determinations about whether or not a second, what they call pivotal study can take place. That’s a larger study that’s done at many centers across the US in maybe 20-plus centers. And then that study is meant to determine the, is the device effective. So the first study is, is it safe? The next study, the bigger study is, is it an effective device.
Do you need a third study before approval?
MATOUK: It gets complicated at that point, I can go in different directions. So not necessarily.
So you need to at least get through the 10 patients, right?
MATOUK: Correct.
Is there anything that you would want patients and their families to know about this?
MATOUK: I think that the biggest thing is that I think I and others believed that NPH is woefully underdiagnosed. And by the time that a patient gets to a surgeon, even if they have NPH, it’s found that they have in NPH it’s often so late that there’s an opportunity has been messed to intervene. And that’s unfortunate. Because really, what we’re trying to address again is quality of life. So it’s not like cancer or if you’ve had a heart attack where there’s not a lot of decision-making to make. You have cancer and you’re like it’s got to come out or you got to have chemotherapy. If you have a blocked blood vessel in your heart and you’ve had a heart attack, you have to open it up. There’s not much to discuss. But here, we have to have like profound conversations about, well, about quality of life and what risk are you willing to take to have a better quality of life. And those are often more complicated discussions. But because of that in part, I think that the condition goes misdiagnosed for a very long period of time and patients will get a diagnosis of Alzheimer’s disease are often Parkinson’s disease. When I see them in clinic, it’s obviously not the case. But people just don’t think of this condition. Not only people, the patients, and their families, but also practitioners, general practitioners. Or they feel that there’s a certain amount of nihilism around NPH where the risk of shunting is just too high for anybody to endure. And while the complication rates are higher than maybe they- we would like them to be, they certainly are not prohibitive for a majority of people that can have the procedure and for the appropriate person, can really have a transformative improvement in terms of their ability to be with their family, do the things they like to enjoy in this latter period of their lifetime. So if there’s any final message, it would be that, be aware that this condition exists. Ask your family doctor or your consulting neurologist about the condition and that you’d like to see a specialist in regards to the diagnosis and that specialist is often a neurosurgeon.
END OF INTERVIEW
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