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Neuromodulation: A New Service Line for the Interventional Radiologist
Olivia Reid • Updated Jun 18, 2024 • 118 hits
Neuromodulation is proving to be a valuable addition to interventional radiology, particularly for managing pain in diabetic neuropathy patients with arterial and venous diseases. By integrating high-frequency neuromodulation, interventional radiologists can enhance patient outcomes and potentially reduce healthcare costs.
Conducting trials to determine patient suitability for permanent implantation is crucial, with early intervention playing a key role in managing neuropathic pain and promoting nerve regeneration. Drs. Dana Dunleavy and Douglas Beall discuss the emerging role of neuromodulation in interventional radiology and detail how the field continues to evolve.
This article features excerpts from the BackTable MSK Podcast. We’ve provided the highlight reel in this article, and you can listen to the full podcast below.
The BackTable MSK Brief
• Many patients who present to interventional radiology may already be suitable candidates for neuromodulation. Coupled with a robust reimbursement for the treatment, neuromodulation is often much more financially viable than providers may realize.
• Neuromodulation trials help determine patient suitability for permanent implantation, with a low number needed to treat (NNT) suggesting high efficacy.
• Objective measures, such as intraepidermal nerve fiber density, provide valuable assessments of neuropathy severity; this aids clinicians in accurately gauging treatment response and guides intervention strategies.
Table of Contents
(1) Adding Neuromodulation to the Interventional Radiology Repertoire
(2) Trial to Implant: Ensuring Clinical Success with Neuromodulation
(3) The Importance of Diet & Exercise in Hashimoto’s Treatment
Adding Neuromodulation to the Interventional Radiology Repertoire
Neuromodulation holds significant promise in managing pain among diabetic neuropathy patients with arterial and venous disease, serving as a valuable addition to interventional radiology practice. By integrating high-frequency neuromodulation, there is potential to enhance patient outcomes while reducing healthcare costs. Although initial hesitation may have deterred some unfamiliar interventional radiologists, the substantial overlap between patients suitable for neuromodulation and those typically encountered in IR settings underscores the natural extension of expertise.
Despite the upfront costs associated with neuromodulation technology, its robust reimbursement renders it an economically sound option for IRs. For instance, conducting an office-based, “test-drive” trial results in reimbursement of approximately $3,500; the lead costs only a few hundred dollars. Alternatively, performing the trial in an ambulatory surgery center (ASC) yields reimbursement of around $9,800. Permanent implantation of the implantable pulse generator (IPG), along with two leads, allows for reimbursement ranging from $31,500 to $34,500.
[Dr. Dana Dunleavy]
I think as we circle back towards the end and think about our colleagues as interventional radiologists, we would never want our patients to be in a wound clinic without also having their venous and arterial disease treated. Similarly, in this situation, we want the arterial and venous disease treated, and we're providing high-frequency neuromodulation, and all of the aspects you said from improved pain scores, improved A1Cs, improved nerve fiber density, what we're hoping is that we have a cost savings to the healthcare system and to our nation in terms of decreased wounds and decreased hospitalization.
In that discussion, what is your thought about why interventional radiologists have held back from offering this and improving access so that you don't have so many advertisements for unstudied pain clinics?
[Dr. Douglas Beall]
They just don't know about it, Dana. I think it's the same thing that whenever I first started, the medical device company didn't even want to let me use it because they thought they would upset the other customers. Of course, that's not true. It's the same thing as kyphoplasty and the surgeons and the radiologists, and it's the companies that realize that, "Hey, these radiologists are actually seeing patients like this," and the device manufacturer for the high-frequency stimulator realizes that.
I haven't been doing peripheral arterial disease in two decades probably, and it's not because I don't like it, I love it, but the point is that I see lots of these patients from a neuropathic standpoint. These are the same exact patients that are present in most of my IR colleagues that do what we think of as a conventional interventional radiology practice. I remember talking to one of my colleagues early on about this like, "Hey, you really should look into this. We're 90 for 90 on these things and patients do great. I bet you have some patients like this," and he goes, "Are you kidding me?" He said, "Most of what I see has this," and it was somebody that does a lot of peripheral arterial disease. That's when I first realized as I took a divergence from IR early on, this is a realignment, this a risk convergence because the patients we treat now have a huge overlap.
One of the disadvantages of this therapy is that it's expensive. These leads and the IPG are expensive. It's technology and that's a disadvantage, but one of the advantages is that it's very well reimbursed. The IR, development of an IR to essentially a surgical subspecialty. That's what IR has become. The IR is no longer just solely a hospital provider like a fish swimming in the stream with his mouth open waiting for food to jump into it. Now, we have to go out and hunt, and we have to change our sites of service and we have to have offices because we are essentially a surgical subspecialty and we see patients. Your mom may not know what you do for a living, but she knows you help Betty Lou and that she can come back and see you. You have what looks like a regular doctor's office, but you have an OR in the back and that's your OBL, your office-based lab. You have the ability to do cases, yes in the hospital where you climbed out of the primordial soup, but you also have the ability to do it in the ambulatory surgery center, the ASC. This is reimbursed in the hospital and it's expensive technology in the hospital. It's reimbursed well, but I want to put some numbers to this so our listeners can scope and scale this.
For example, an office-based trial, a test drive, is reimbursed at about $3,500 in the office, and the lead price is a few hundred dollars. The ASC reimbursement for trial is right around $9,800 in the ambulatory surgery center. Permanent IPG placement and two leads, it reimburses between about $31,500 and $34,500 for a permanent implantation. Out of everything that we do in the ASC, this is the single best-reimbursed item, and it's the single thing that allows us really to keep the doors open and the lights on. This is something I think the listeners should know about. You're not having to do a lost leader here. This is not just simply charity work for people with PDN, a disenfranchised group. Yes, this is a disenfranchised group because we previously hadn't had anything to treat them with. Then, our colleagues are doing great work, they do great work for arteries, peripheral arterial disease work, angioplasty and stent placement. Their partners, colleagues are doing great venous work and they come out with vascularized limbs. They're not going to get ulcers, but boy, they sure run the risk of wearing an ulcer on their foot because their foot is numb, or if it's painful, it drives them crazy. It disrupts their sleep, it creates a chronic pain scenario. It seems like we should be able to combine these two things.
As I mentioned, the single best people to do this, neuromodulation spinal cord stimulation, are interventional radiologists and whatever I've taught courses for spinal cord stimulation, neuromodulation, I've taught hundreds of these. You can always tell when IR steps to the table, when there's multiple specialties involved, you just show them the epidural highway and bang, the lead is in place before you can blink your eyes. You can always tell the skillset and the visual-spatial skill of an IR. This is not only in somebody's wheelhouse, this is a huge patient population that you can, not only take care of their vascular problems but you can hit for the cycle, you can take care of all the vascular problems plus you can take care of the pain and these are almost identical patient population.
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Trial to Implant: Ensuring Clinical Success with Neuromodulation
Neuromodulation trials provide valuable insights into determining patient suitability for permanent implantation, making timely authorization of the treatment post-trial imperative to maintain therapeutic benefits. The low number needed to treat (approximately 1.3) highlights the superior efficacy of high-frequency neuromodulation compared to traditional treatments like gabapentin and serotonin reuptake inhibitors. Additionally, intraepidermal nerve fiber density serves as an objective measure of neuropathy severity, allowing clinicians to accurately assess treatment response.
Continued research seeks to explore the benefit of neuromodulation as treatment for diabetic foot ulcers. Due to the high associated mortality rates, it is important to intervene early and strive for comprehensive neuropathy management strategies. While hemoglobin A1C levels indicate overall diabetes control, they may not directly correlate with the severity or improvement of neuropathic symptoms, necessitating a nuanced treatment approach. Ongoing trials focused on neurologic improvement aim to highlight disease modification in peripheral neuropathy, potentially shifting the focus from merely alleviating symptoms to promoting actual nerve regeneration.
[Dr. Dana Dunleavy]
Yes, I think that's such a rewarding aspect of it. The trial is so easy for us and for the patient and for the family and it really is unique in that you can do this very simple test drive as you said. You and I both try very hard to make sure that authorization is in place for the PERM because these patients finish their trial. Not only does it change their life, but as that trial finishes, they go back to the pain they were in before. They're pretty mad, they want that success that they had as soon as possible. To your point, it shouldn't be months down the road after the trial ideally.
Again, that's a really nice aspect. I want to get a little bit nerdy and go back to some of the things you mentioned in terms of the success of high-frequency neuromodulation. You've used terms like number needed to treat with vertebral augmentation, but we also have some data on that in terms of gabapentin number needed to treat is about eight, serotonin reuptake inhibitors number needed to treat is about six. With high-frequency neuromodulation, the number needed to treat is only one. What does that mean?
[Dr. Douglas Beall]
NNT, we love NNT because it gives people personal experience. How many people do you need to treat to have success? You can identify the treatment success as however, you want. For me to have a responder means I cut their pain 80% down, decrease. That to me means they're a responder. Gabapentin is around eight. I've seen a study recently that said that was a little bit more permissive on the gabapentin and said the number needed to treat for some margin of success, which it didn't say or I didn't see it, was three, but the number needed to treat for a complication or side effect was four. That's the thing about gabapentin, by the time you get up to the point where it's making a neurologic improvement and the neuropathy, it's also giving a side effect because of the way it functions. A lot of people don't like it because of the fog that leaves them in. It just gives them a strange feeling. It can make them sleepy, and it's the same thing with the serotonin and norepinephrine reuptake inhibitors: the dual oxetane. A lot of these things that patients just don't like and they just don't like it well enough to continue to do that.
The number needed to treat spinal cord stimulation is just a little over one. Basically, it's right at 1.3 to be specific. Almost every single person that comes through the door will have a treatment success as how it's defined. It's not everyone, if it were everyone it would be one. For every person that comes in, that means the number needed to treat for a treatment success, one-to-one that would be everybody. If it's one and two, the number needed for treatment success is two. This should give everyone an idea about how effective this is.
If almost everybody gets treatment success, it's a pretty darn good treatment. It puts it right up there with everything that we do. It puts it up there with vertebral augmentation and we have mortality numbers for that. The number needed, we've never measured the number needed to treat for vertebral augmentation, but it's going to be right at one, maybe slightly over. This is one of the few therapies I know that are just reliable to the point where it's almost money in the bank that you know that the person's going to get better.
[Dr. Dana Dunleavy]
To get nerdy once more, because you and I are known for this, what is intraepidermal nerve fiber density? And, in talking about that, I think that our nation has done a wonderful job of improving awareness of breast cancer diagnosis, screening treatment. Not as well with this, about treatment for diabetes, diabetic neuropathy. To start, as we talk about nerve fiber density, what has a higher mortality, breast cancer or a diabetic foot ulcer?
[Dr. Douglas Beall]
Yes, exactly. What happens with the diabetic foot ulcer is they get an ulceration and then they have vascular problems, they get it infected, then they get an amputation and their mortality rate is right up there and exceeds many cancer mortality rates. This is, by the time somebody with a diabetic foot ulcer, that is the past time probably to throw everything at it. You want to get the person before they develop that ulcer and you want to make sure, as we stated previously, that the arterial supply is adequate, you want to make sure the activity is adequate, and in addition to, we always say PDN, with the P being painful, just the diabetic part of the numbness part of it is it can wreak havoc. If somebody's diabetic, they have no feeling, they walk over a straight pen, I've seen this, pencil, they stub their toe, they just have an ulceration from ill-fitting shoes. We've seen all of this and that is the tipping point. That's the beginning of the end for that lower extremity as it goes through and the ulceration can't heal, they can't continue to can't feel it, they will get, transmetatarsal amputation, or show parts, they'll get a long BKA, will shorten up to short BKA. This is just the beginning of the end for a lot of people like this and that's one of the things that the mortality for these patients is exceedingly high. I would like to really catch these people before that happens, and that's why neurologic study is so important.
We measure the fiber density, and that's an objective finding on transdermal biopsy. You can measure the motor sensory and the reflex improvements, and you can measure the two-point discrimination, the numbness, and these are things that are objectively improved. At least on the two-year data, we found that two-thirds of the patients had objective improvements in these categories, and I think sometimes we will focus on the pain out of the PDM, but the numbness is actually one of those things that can really lead to an ultimate disaster down the road.
[Dr. Dana Dunleavy]
How about A1C?
[Dr. Douglas Beall]
The hemoglobin A1C for the clinical trials was right at seven. That's a little high, it's not bad. To be in the trial, the sensor PDM, you had to have a BMI less than 45, which is very generous, and a hemoglobin A1C less than 10, which I think is incredibly generous. These people had long-term neuropathic problems. They had years, six, seven, eight years of neuropathic problems, and so to take people like this and then measure what happens to them is really classic. These are typical patients.
I think there's a misnomer that if you have your hemoglobin A1C right around six to seven, that's pretty good for a diabetic and you shouldn't really have problems and that your neuropathic symptoms will improve, but that is just absolutely false. That is not true. You can have well-controlled blood sugar as measured by hemoglobin A1C that's right around seven, and it will not remit. It will not improve, it will not be of any benefit for the neuropathic problems. It can benefit other things to keep your blood sugar under control. I'm not making the argument that blood sugar control is not important, it's critically important, but it won't improve your neuropathy.
What is seen in the sensor PDM trial is these people came in and they were pretty much typical and they were productive members of society keeping their hemoglobin A1C under descent control right around seven. They still had refractory symptoms until the point that they underwent spinal cord stimulation. This is compared against conventional medical management, and as we know, conventional medical management doesn't do hardly anything. Typically, it's mediocre to poor in terms of treating diabetic neuropathy.
I'm really excited to see what the objective findings will show us, a trial focusing on the neurologic assignments and symptoms and improvement, and having just gone through an investigator's meeting where the neurologic exam and the assessment and evaluation was gone into in-depth, and now as part of another trial, I'm going to have to do that. I realize that this is very accurate. This is going to provide good data, and it's a lot more involved than just saying on a scale from 0 to 100, can you mark where your pain is, or on a scale from 0 to 10, where are you today in terms of your pain. It's much more extensive than that. I think we're going to get great data. We should get good improvements, past performance to predict future results. I think two-thirds of those people will demonstrate good objective improvements, and it's going to be interesting to see that the focus may change on not only symptom modification remitting, but it will focus on disease process. It will actually cause improvement of peripheral neuropathy.
The Importance of Diet & Exercise in Hashimoto’s Treatment
While medication replaces thyroid function, lifestyle modifications can counter systemic inflammation responsible for symptom burden. Dietary changes that counter inflammation include reduced simple carbohydrate intake, increased antioxidant intake, and increased B vitamin intake. Habit-based changes that counter inflammation include effective stress management strategies and regular exercise.
[Dr. Ashley Agan]
With your T3 and T4 that you're prescribing, obviously that's going to help them with the symptoms that we talked about, the fatigue, hair loss, being cold, all these things. Does it do anything to the natural progression of the disease of Hashimoto's? Does it change what's happening from an autoimmune standpoint, or is it mostly just helping with the symptoms that are related to that?
[Dr. Dana Gibbs]
That's a really good question. Once you've got a patient feeling better and they trust you, then you can recommend other things like, "Here, I really think you ought to be taking these B vitamins. Here, I really think you ought to pay more attention to the standard American diet that you're eating that is destroying your pancreas. Here, I really do think you ought to start exercising. I really do think that you ought to start meditating. Here's how I think you ought to do it," blah, blah, blah.
Those are the things. Anything that reduces inflammation, reduces stress, is going to help that person reduce their tendency for high antibody levels. Antioxidants, all the things that lifestyle medicine doctors do to try to help their patients feel better also work on hypothyroid or Hashimoto's patients because that disease, it doesn't exist in a vacuum.
Podcast Contributors
Dr. Douglas Beall
Dr. Douglas Beall is the Chief of Radiology Services at Clinical Radiology of Oklahoma.
Dr. Dana Dunleavy
Dr. Dana Dunleavy is a musculoskeletal and vascular IR in Buffalo, New York.
Cite This Podcast
BackTable, LLC (Producer). (2024, January 29). Ep. 40 – Innovating Pain Management: The Role of Spinal Cord Stimulators in Outpatient Care [Audio podcast]. Retrieved from https://www.backtable.com
Disclaimer: The Materials available on BackTable.com are for informational and educational purposes only and are not a substitute for the professional judgment of a healthcare professional in diagnosing and treating patients. The opinions expressed by participants of the BackTable Podcast belong solely to the participants, and do not necessarily reflect the views of BackTable.
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