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BackTable / MSK / Podcast / Transcript #30
Podcast Transcript: Image-Guided Headache Interventions
with Dr. Dan Nguyen
In this episode, guest host Dr. Jacob Fleming interviews Dr. Dan Nguyen about MSK and neurologic pain interventions, specifically how he evaluates and treats different types of headaches at his practice. You can read the full transcript below and listen to this episode here on BackTable.com.
Table of Contents
(1) Dr. Nguyen’s Transition into Clinical Interventions
(2) Correlations Between Clinical Evaluation & Imaging
(3) Building A Headache-Centered Clinical IR Practice
(4) Various Headache Pathologies
(5) Imaging Techniques: CT, Fluoroscopy & Ultrasound
(6) The American Society of Spine Radiology (ASSR) Benefits & Contributions
(7) Treating Trigeminal Neuralgia
(8) Radiofrequency Ablation Complications: Anesthesia Dolorosa & How to Avoid It
(9) Advice for Implementing Headache Interventions
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[Dr. Jacob Flemming]
Today, we're happy to continue our spine and pain-related topics with another world expert joining us today. Dr. Dan Nguyen, Interventional Neuroradiologist from Neuroradiology and Pain Solutions of Oklahoma. Dr. Nguyen, welcome to the show. Thanks for your time.
[Dr. Dan Nguyen]
Thanks, Jacob. It's a pleasure being here. I've been a fan of yours and BackTable for some time now.
[Dr. Jacob Flemming]
We're excited to have you today, and I have to say we're very lucky. We recently had the chance to discuss with Dr. Jack Jennings, and we're continuing with the ASSR dynasty. We are lucky to have another prior President of the American Society of Spine Radiology today. We really appreciate your expertise and coming on. You are an expert in many of these areas of pain interventions. One of the things we really wanted to get your expertise on is the field of headache interventions, which is something a little bit out of the ordinary for radiologists to be practicing. Really excited to dive into this topic today. Before we begin, could you just tell us about your life and your training path, how you came to be doing pain interventions in your career. Tell us a little bit about your current practice.
[Dr. Dan Nguyen]
Oh, okay. wasn't born in the US. I, actually, immigrated here back in 75 from South Vietnam. We, through the gracious government here in the US, came to Northern California. It was not a planned trip and we stayed there, and somehow in two years, my mother and father bought a house, and they've been residing there. I left there. I went to college there and then I left there to go to medical school on the East Coast, and I have not returned since then, back in the early '80s.
[Dr. Jacob Flemming]
You've been all around, all over since then. You've really traveled all over the US during your career.
(1) Dr. Nguyen’s Transition into Clinical Interventions
[Dr. Dan Nguyen]
Through my journey, one of the things I really enjoyed was meeting different types of people, what their passion was and learning from them. Many of those have become, and stay still, are my friends to this day. When I was in Washington, D.C., my mentor, Dieter Schoeninger, got me interested in the spine. Then in that area at that time was like the Mecca of vertebral augmentation. As you know that came from France, but it was brought to the Virginia area. Then in the Washington, D.C. areas where people like Gregg Zoarski, John Mathis, Orlando Ortiz, Wayne Olan, Kiera Murphy, and so on, they were all right there within driving distance from me. I met them and learned to respect them, and became friends with them, and it got me this whole journey of intervention, which I never knew of during my initial going to radiology.
[Dr. Jacob Flemming]
Yes, that's pretty amazing that so many of the world experts were concentrated in that local proximity, and you carried the torch on from them. It's very exciting to hear about that.
[Dr. Dan Nguyen]
Yes, it was just a great experience. Then, I came from Washington, D.C., and I went next to Penn State and spent the next 13 years up there. I had a great opportunity to build a division, and from there, I spanned out from what I was set to do was build a Division of Diagnostic Imaging, but my focus was, always on the side, intervention.
Despite doing stroke and aneurysm work at that time, I became much more interested in the musculoskeletal and neurological pain that led me to what I'm doing today. I hone my skills and learn from a lot of great and more experts than me at that time, and just got to dive into the anatomy and the function, and how can I perfect my skill set through those interactions.
[Dr. Jacob Flemming]
Amazing. You've had an exceptional career in academic radiology, and more recently, you've brought your talents to the community level in Oklahoma City. Can you tell us about that transition, and what's the current practice like?
[Dr. Dan Nguyen]
Absolutely. That was a focus. I've been thinking about what I want to do for the rest of my career. I had a wonderful time in academia. I met a lot of friends and students, and many of those went to do great things, but inside, I knew I wanted to do something different. About, I would say, probably six, seven years ago, I had a conversation with one of our mutual friends here in Oklahoma City, Dr. Beal. He talked to me, he told me, "Come to Oklahoma City," and I went, "No, I'm not going to." He had a Vision Oklahoma and I went, "I'm from the East Coast, big city."
When he invited me one weekend to come here with my family, I took that offer, and I fell in love with the area, and what I can do here. That sets the motion to what I want to do. I want to focus on something different at that part of my career. I came here and opened a practice here, and I'll focus on patient outcomes, latest technology, bring the treatment to them, integrate research, and then, hopefully, soon I'll be doing education, just like I did in academia. But now at this level where I can have some control over it.
[Dr. Jacob Flemming]
Very exciting. It sounds very complementary to your experience so far, and really cool that you get to bring those skills that you've honed over decades into a different environment. Is your current practice predominantly interventional and clinical at this point?
[Dr. Dan Nguyen]
It's completely, I would say, 95% clinical. We do some trials here, clinical trials, and then I still read films because I feel like some aspect of it, I want to maintain. I've learned all through these years and I don't want to lose it, so I still do that, really just maintain my skill more in that perspective. It's really just purely clinical. I see patients. I treat them. I see them back and some of these patients I have in our practice, they've been with me for the last four years. It's a long-term relationship that I have with a lot of these very dear-to-heart patients of mine. Yes.
[Dr. Jacob Flemming]
That's wonderful. That sounds really gratifying to be able to build up that longitudinal relationship with the patient sometimes in radiology. Especially in training, we don't get the opportunity to do that so much. We're consulted for an intervention, often in the acute term, and we don't have the opportunity to see that. I imagine that adds a different dimension to your work.
[Dr. Dan Nguyen]
That's the one thing that I must say that I see a transition in our field. I think when I entered this about over 20 years ago, it's exactly what you said. It's like a point of care, and then that's it. I've been seeing many, many of us have transitioned to this new model, and I presume in the coming years, more and more, like yourself, will be doing this as well.
That's the only way to deliver best of care because you know these patients as well as anyone else, and what they need, and stuff like that. If we don't have that continuity of care, we tend to lose that perspective. We can depend on someone else who may not know the patient from the way that them, and their pain, and their location of pain. I think I'm seeing that quite a lot in our field, and I'm very happy to see that, actually.
[Dr. Jacob Flemming]
I agree completely. It's been really exciting to see that organically happening over the last few years. I would say that earlier on in the field of interventional radiology, which, again, really encompasses VIR as well as interventional neuroradiology and musculoskeletal radiology, really any radiologist doing interventions. We have the imaging expertise and the procedural expertise, and we have the theoretical clinical acumen.
It's just that it's not so much typically a focus throughout our training. Earlier in our field's history, I think we didn't really have these sort of role models for how that's done. Now our entire field is benefiting from a lot of the trailblazing work of people like Doug Beal, Wayne Nolan, and yourself, who have gone out and shown that we can do this. It adds a very gratifying and important element to the work.
Much better to be able to evaluate the patient yourself rather than receive a request for an L4-5 epidural steroid injection, but when you, if you, as a radiologist, examine the patient yourself and correlate with the imaging findings, you say, "This doesn't really correspond with radicular symptoms," and then you use all that to come up with the best treatment plan. It just seems like a better way of doing things.
[Dr. Dan Nguyen]
Absolutely. Absolutely. It could be starting just a basic epidural, but then you will see, "Wow, the patient, actually, has lumbar spinal stenosis. There's other things that I can help them with." It takes on that role if you specifically engage yourself with the patient in a continual care pattern.
[Dr. Jacob Flemming]
Absolutely. On that topic, how would you say that your background in neuroradiology and specifically your experience with interventional neuroradiology, how does that inform your diagnostic and therapeutic approach bringing those skills in?
[Dr. Dan Nguyen]
That's the groundwork. I think it's very important that every patient that comes to my office, my staff know that, despite that we have an official report elsewhere, that I specifically ask them to bring a CD. On rare occasions, they have films, but a specific CD of an outsize to all of them, anything that pertains to the area of their pain, bring them.
Every patient, I look at them and, actually, show them on the TV what I'm thinking, and so they're understanding why I'm doing this, and because of the background of imaging and spatial relational anatomy, you get to appreciate the patient. Like where the pain and you, actually, most of the time, you do find things that were missed.
No fault to anybody. It's hard to study without any information remotely, and so you have a patient right here, you're looking at them, I say, "Okay. Wow. There it is. There's the problem." You point out to the patient, their eyes, they go, "Wow. Okay.” They take a role in their care now, they understand why I'm doing this, and that's very important. I think the background I had in imaging really served as a baseline that launched the next level into intervention.
[Dr. Jacob Flemming]
I love that. In our training, we spend the majority of our time on imaging, perhaps some would say to our detriment, but I don't think so. I think that it adds a different dimension to the clinical evaluation. Like you said, we never take the report at face value, even if it's done by a colleague, a radiologist of ours who we agree with and admire their work. It's just second nature based on how we function in residency and fellowship to always look at the imaging ourselves and confirm that. Also, it, definitely, is crucial for procedural planning when it comes to that point.
(2) Correlations Between Clinical Evaluation & Imaging
[Dr. Jacob Flemming]
On that note, I'd, actually, like to transition a little bit to talking about some of the headache interventions. One of the things I've been thinking about with this, and I'll say, I haven't performed any headache interventions at this point in my career other than for CSF hypotension. I know a lot of these interventions involve really very eloquent and small real estate, particularly at the skull base.
As radiologists, whether we're trained in neuroradiology or not, throughout our training, read thousands of head CTs. It's probably one of the single most common studies that we read, and often for the indication of headache.Yet, most of the time, our impression is sort of, "No acute intracranial abnormality." I'm wondering if you can talk about the clinical evaluation of headache, and then how the imaging aspect comes into that? Are there often any imaging correlates to these headache syndromes, and how do you spin that all together?
[Dr. Dan Nguyen]
I think the imaging that we see day in and day out, a lot of it coming from the ER. They look for big stuff. The big intracranial hemorrhage, or a mass, or unexpected mets, or something. Yes, we see that, but even normal people have headaches. You look at that, most of the time, it's normal. Then it's really hard to correlate that clinically, unless you have a patient sitting in front of you and describe to me, "Doc, I have this pain right over my eyebrow," or, "I have this pain right in my jaw lines."
Some specific region now gets you thinking of the neuroanatomy supply of the face. Then you go back there and look at that and sometimes you find something, but most of the time it's negative. Certain things like trigeminal neuralgia, they have this pain, an electrical pain over their face, but you don't see anything on the imaging. Every once in a while a vessel next to it, which probably was not, to be fair, difficult to catch in the front end from the original interpreter. Yes, you can suggest that maybe there's a vascular compression syndrome that may be causing that.
On rare occasion, you find that most of the time you don't, but it's good. Then now you go back to your understanding of the neuroanatomy of the face. Then, you troubleshoot, "Okay, if it's in the front of the ear, maybe it's a auriculotemporal nerve that may be bothersome." Some other areas may be supraorbital, infraorbital, mental. There's different nervous supplies of the face and our understanding of the anatomy helps us to hone down now and say, "Okay, we'll try the most superficial approach and then we'll dive into the deep part of the skull and facial region as a secondary backup option.
(3) Building A Headache-Centered Clinical IR Practice
[Dr. Jacob Flemming]
When you started your practice in Oklahoma City, what was your approach to raise awareness that you were offering these therapies? What physicians did you approach and how are patients coming to you now?
[Dr. Dan Nguyen]
Yes. When I came here, as anyone else, no one knew of you. I just start with the basics of what I know at that time. What I knew was exactly what you say is spontaneous intracranial hypotension. I start with the group of practitioners that deal with this the most, which is most of the time the headache doctor. There's not too many of them in most cities, but each main center will have one or several of those.
That's how I started. I introduced myself and said, "Okay, well, there's this entity, and then the conversation led to other areas, like what I'm doing today. Getting that face to face interaction with someone, the old-fashioned way. It's very effective. Most of them I give them my cell number freely. I say, "Text me, call me, whatever you need to do that." From there, I also obviously had to learn about the patient directed digital marketing for my kids and how we can do that part of that too.
Before you know it, people know there's someone here in Oklahoma that does this thing. It infiltrates very quickly because there's not too many of us doing that too. Everyone's searching for a partner in this arena and that's how it builds up from here, organically, so to speak, with some intent. Sometimes you can go to this center and I offer to do a grand rounds on headaches and I talk about different things. It's a combination of things. Since I'm not in a medical center, so to speak, I have to purposely go out and develop my relationship with different people in this area. That's how I started.
[Dr. Jacob Flemming]
Excellent. A bit of deliberate practice building with respect to the headache, but it sounds like as things have gone on, you're getting a mixture of both physician referred and self-referred patients.
(4) Various Headache Pathologies
[Dr. Jacob Flemming]
You're probably seeing a wide variety of the manifestations of headache. With that, I imagine starting out from SIH, you had to, basically, bring more tools into your armamentarium. Can you just briefly talk about the different headache entities? Maybe just list the top five and what are the therapeutic approaches for those?
[Dr. Dan Nguyen]
Yes. Most of this, what I'm saying right now, I did not know back then either. It's one of those things that I think when you're doing something new, you start to dive into it and you start to read more. You start to look at the research and other societies, what they're doing, and it gets your interest. I go, "Wow, this whole area is a little more broader than I thought."
From there, typically today, I'm seeing a lot of the migrainous headache that has an occipital component to it. That could be just ranging from musculogenic nature, where we can do some simple trigger point to really an occipital painful with palpation, occipital neuralgia, where we can do a test injection and then we can do some ablative therapy. Then bring on neuromodulation, peripheral nerve modulation. I didn't even know what that was four years ago when I came to Oklahoma. "What is that?"
Those things I learned from my colleagues in the interventional pain world through my interaction nationally with them and brought that into our practice as well. That's the most I think of occipital neuralgia that I deal with. The other one is a cervicogenic headache, which you have to rule out. There's some people who have pain from their spine. I did not know there was a nice cervical, trigeminal connection in the brain, where your pain in the neck could manifest along the face, and vice versa.
There's that deep inherent connection and so you have to work through that too, was it coming from the spine where you're having pain in the face? Typical things you do for that is, okay, well, I look at the x-ray or CT or MRI, whatever that is. And see if there's any potential because of that and do some trial injection and then go from there to ablative therapy and, again, neuromodulation if needed.
Of late, I've been getting a lot of trigeminal neuralgia, mainly from trigeminal neuralgia centers around the Oklahoma State connection and people with MS are getting a lot of this. Certainly, deal with it from an imaging review and looking for vascular compression, but they have these really terrible, shocking pain that I feel so badly for these patients to live with this. We've been looking at ways to deal with that depending what region it comes from. Whether it's V1, V2, V3.
We know from anatomy there's areas of where these nerves come from. We, typically, do a trial injection of those areas like V1, supraorbital, suprachoclear, and then V2, infraorbital, and then frame of rotundum, we can access that through CT if you need to. Then V3, superficially mental nerve, and then could be as far back as Fremont Valley where you can do that. I discover, I was very shy with fluoro beginning, but I discovered fluoroscopic guidance is so easy once you get to know where you can see it and much easier than CT to get there.
(5) Imaging Techniques: CT, Fluoroscopy & Ultrasound
[Dr. Jacob Flemming]
I get a little bit antsy when I'm looking at fluoro pictures of the skull base and a needle going through someone's face. In radiology, we look at skull radiographs. To me, the diagnostic skull radiograph probably has one of the lowest yields, and yet, there's quite a bit that you can see on it, especially for procedural guidance. Could you talk about the movement from CT to fluoro and how did you mentally get over that hump?
[Dr. Dan Nguyen]
You're, absolutely, right about this. I am so appreciative of the early days of fluoroscopy, what they used to diagnose things. We're talking about decades ago and because they see so many things on there that we don't appreciate today, all the pathology. It took me looking at the fluoro picture and then looking side by side with the MRI and the CT. I look at it and go, "Well, if I take this approach, what is the worst thing that I can do? What things do I need to avoid?"
When I look at the approach to the foramen ovale, I go, "Wow, it's not a real lot of things here. It's not a carotid that's going to be there or anything." If I take this angle, there's really not a lot of things other than just sharpening my skill of advancing the needle meticulously without changing the direction and causing a lot of aggravation because this is a very sensitive area of the face.
Once I overcome the unknown of, "Oh, wow, this is putting someone's needle into the face," Once I understand the anatomy, it's really pretty safe if you just develop a right visual approach to it. That's what we say. I love to look at that. Once you have that, it's a straight shot into the foramen from the cheek area.
[Dr. Jacob Flemming]
It's really encouraging, much easier than expected, it sounds like.
[Dr. Dan Nguyen]
It is. Like I say, understanding the anatomy and looking at the things that we know from a cross-sectional image and going, "What is there that I have to avoid? That would be devastating if I hit it?" Once I overcame that, I didn't see anything and it was just a matter of getting used to the view from the fluoro perspective. It's so easy to do. It's just like C1, C2. You know what's going on there. I find it much easier doing fluoro than CT guided, C1, C2.
I can do a fraction of the time doing fluoro because it doesn't take a lot to set up. You can make some minor adjustments when you get the needle, which CT, sometimes when patients move a little bit, then you have to reset again. It's just a little more time consuming. There are times when you have to do CT, but there's some transitional phase where you just have to be yourself, look at the imaging and see what is there that I need to be not hitting? Once you see that, go, "Wow. Okay." Then you just overcome your fear.
[Dr. Jacob Flemming]
Sure.
[Dr. Dan Nguyen]
Like heights.
[Dr. Jacob Flemming]
Yes. It's a mental block. Once you understand, like you said, the procedure is done in the same manner as in CT in terms of the needle trajectory. We just are using image guidance in a different manner. I think it's something that's very important for trainees of my cohort in that we do a lot of procedures under CT, current resident and fellows in training. I think it has to do with probably availability and the comfort level. It's understandable. We do a lot more complex interventions, including drainages and things of that nature.
With that variable anatomy, it is good to have the three-dimensional aspect. When you're doing something like a trigeminal nerve block, a gasserian ganglion nerve block, you know, as you said, you're not going to be impinging on the carotid. There's not other critical structures nearby, and you have a little bit more of a reproducible approach. Knowing that CT and fluoro are both available and, of course, always using the approach that's the safest for the patient, but knowing that it's, definitely, feasible with both.
[Dr. Dan Nguyen]
There's one other modality that I want to give a little attention to. It's ultrasound. I think we have, in our radiology, we use ultrasound quite a lot, but maybe not in certain subspecialty in radiology. That is another modality that I integrate into our practice, especially in the superficial face, and then also peripheral nerves in the extremities too. That's another thing that I think has a large part in our guidance. Sometimes it's, actually, easier doing that way than any other ways that we're, thus far, been introduced to.
[Dr. Jacob Flemming]
Absolutely. A lot of love for ultrasound. It's such a dynamic modality. We tend to get quite a bit of exposure to this during our training. Adapting it to some of these places where probably in training we haven't used that much in the upper cervical spine or the face, it's, definitely, an important thing to do.
You mentioned a few minutes ago that you've learned a lot from interventional pain colleagues.I really want to emphasize that point because a lot of people in that area have really done some of the pioneering work on these headache interventions. In particular Samer Narouze, who, anesthesia, an interventional pain titan, who, his book that you recommended to me, Interventional Management of Head and Face Pain, is sort of the current Bible on these things and represents culmination of a lot of the anatomic studies and development of these techniques over time.
It's just something that I want to put out there. I think that our specialty, radiology and the interventional subspecialties, we gain a lot by interfacing with the specific interventional pain and pain management communities because we have complementary approaches. A lot of this work has been done by people like Dr. Narouze who were singularly focused on these areas. In particular with ultrasound, he's described a lot of the ultrasound-guided approaches to upper cervical blocks. We learn a lot by incorporating those approaches, I think.
[Dr. Dan Nguyen]
You're so right there Jacob. It's one of the things I think makes the whole field, and not just individuals, as a society or if you always learn from each other. That's something that I have always carried with me, is that sometimes I have my ways of doing it. I've always kept my mind open about what other ways people are doing, the same thing in different ways. That's the only way you get better, is you learn from each other.
(6) The American Society of Spine Radiology (ASSR) Benefits & Contributions
[Dr. Dan Nguyen]
I learned so much from my surgical colleagues doing spine and neurosurgical colleagues, how they do it and the approach they do, I incorporate into my practice on the other areas of the body. My goal, one day, is with my recent opportunity from a national society perspective, is trying to have a little more crosstalk with the interventional pain, especially with the ASSR or any of the ASNR, trying to get more interventional pain integration into our programming and work through between several society to try to get a better outcome. We learn so much from each other and that's how we're going to grow as a whole. I can't agree any more with that. Dr. Narouze was one early mentor of mine trying to introduce me to this area. I really respect him.
[Dr. Jacob Flemming]
I, absolutely, agree with all that. I just have to say the ASSR meeting, I believe it was '21 during your tenure as President. That was in the midst of COVID, so things were pretty virtual. I'm sorry, it may have been 2020 or 2021, but it was a fortuitous occurrence for me because I remember I was on Twitter and I saw that the ASSR shared, "Our annual meeting is going on. It's virtual. $25 for residents."
That was the quickest and best $25 I've spent. It was an amazing meeting. I learned so much just about how many different interventions are coming out in the spine and the spine related world. I really loved the interdisciplinary nature of it. We had anesthesiologists, neurosurgeons, interventional pain specialists, and, of course, many different neuro and musculoskeletal and interventional radiologists sharing these different aspects about their practice and the cutting edge.
For me, that was a huge moment in my training, realizing that not everything interventional radiology is necessarily showing up at the more mainstream IR meetings. I tell almost everyone I know that ASSR is one of the best meetings you can go to for this area just because it's so broad. I do want to commend you. It was an excellent meeting, especially given the circumstances with COVID throwing everything out of the loop and not being able to be in New Orleans directly. I really hope to see the ASSR continue that momentum and advance this area in that interdisciplinary aspect.
[Dr. Dan Nguyen]
I'm so happy you said that because it was nerve-wracking when I could not have a meeting in New Orleans. I was waiting so long for that and I had so many great plans for that when that was pulled underneath me. I was very disappointed. Then the opportunity came at that point to make the meeting bigger. I purposely made it bigger than usual.
I want to integrate as many multidisciplinary people into that meeting. Like I said, I had Dr. Deer, Dr. Saeed from the Aspen. We had people from neurosurgical, orthopedics. It was just people that share the same passion in treating a certain body part. That was my goal. I said, "I'm going to make this bigger instead of a typical two session, I will double that."
We were able to get a lot of people into the meeting and get a very multidiscipline discussion about certain pathology other than headache and spine, but many other ways and imaging too. A lot of those colleagues told me, "Wow, I didn't realize you guys have such a society. I thought you guys would just stay in imaging." I go, "No, no. That's our strength, that's our core, but we do many other things." I'm hoping to see that this upcoming year as well.
[Dr. Jacob Flemming]
Excellent, we'll definitely look forward to that. There's no question that the future of medicine is multidisciplinary and benefiting from that cross-pollination that you've talked about. I think that it's a positive sum game for the different specialties in the world of spine to be communicating together, sharing techniques and insight. That way we can all better take care of patients.
(7) Treating Trigeminal Neuralgia
[Dr. Jacob Flemming]
These problems, headache, and low back pain, they're not rare. There's not a small market for them. Most adults in their life are going to, at some point or other, struggle with these sorts of things. The better we all can be as physicians, clinicians, and for us in particular as interventionalists, that's only good for the patient. I really commend that and really happy to see things growing in that area.
I'd like to take it back to talking about the procedures a little bit. You were giving quite a description about the trigeminal neuralgia approach. This is one in particular that I think among headache disorders, it really stands out, at least to me, because as you said, this is often debilitating, lancinating pain. Once pharmacologic therapy has sort of been maximized or has been found to be ineffectual, interventions, or aside from cyber knife surgery, could be one of the few options.
This is a classic interventional radiology scenario where there really is no other option. We can potentially provide an excellent and minimally invasive alternative. Could you just talk about your approach in terms of applying the diagnostic block and then the ablation? What are the specifics in the ablation procedure and what are some things to watch out for when you're treating these patients?
[Dr. Dan Nguyen]
Yes, so trigeminal neuralgia, you think of the main three branches of the trigeminal nerve, the gasserian ganglion is deep to the foramen ovale. It's in there. To approach that, if you have suspicion of a certain branch or regional area, I usually try to do the most peripheral nerve branch. I said, if it's V1, I look at supraorbital, supratrochlear, and that I use ultrasound to get to. Pretty easy, very superficial. You can see it, ultrasound, the tunnel.
If it's V2, I, typically, look at infraorbital as one aspect, and that's ultrasound. The foraminal rotundum deals specifically with V2. If that's something we look at to do, and that will be a CT guidance to get into with this thin needle. Then if it's V3, again, I look at the mental nerve, sometimes the alveolar nerve, just behind the angle of the jaw. That's another option we can try to get there. Pretty accessible.
Then the ovale we have spoken about, where that usually is a test injection. If this test injection, diagnostic injection, proves to be fruitful in terms of giving them some relief, then we usually talk about RFA as the next possible thing. Which is Radiofrequency Ablation. It's the same technology we use everywhere else in the body. Lately, I've been trying to look at other ways, some neuromodulation techniques out there. The unfortunate part right now, a lot of the neuromodulation we have out there is not deemed above the head. It's really head down.
I think that's an exciting field that people are working on and, hopefully, one day get approval to try to put these small leads we have now to put next to those nerves and stimulate it so that they don't send the pain signal back to the brain for interpretation. There are devices out there that we can start to consider. I'm starting to look at ways to try and apply that now, but it's not mainstream because approval is a bear with this insurance company in these areas.
[Dr. Jacob Flemming]
Yes, absolutely. As we've talked about with Dr. Beal before, often the regulatory apparatus lags significantly behind what we're technically capable of doing.
[Dr. Dan Nguyen]
Yes. Then another area of the face pain that I've discovered is the grand central station because so much parasympathetic and somatic nerve goes to the sphenopalatine ganglia.
That area is a small little area behind the maxillary sinus. I knew from my vascular days, other than the internal maxillary area and some of the things that go in there, it really didn't make too much sense for me to ever be in there for any reason. It is a very highly neuro-rich network of the face and mouth and pain in the face. If the other one doesn't help and if the distribution is a little broader, more than just one territory, that's another area that I target. While you can do this effectively using fluoro, CT is much easier as you may have seen some pictures. You see it and you target the superfine and just get the needle there. It's pretty effective and with this, we go for our RFA there as well.
[Dr. Jacob Flemming]
Excellent.
[Dr. Dan Nguyen]
Those are typical, the trigeminal, facial pain, the area that I might approach. That's in the front. Then the back, there's the occipital, there's the auricular temporal, there's a greater temporal nerve. There's some other nerves back there that we can look at as well for the head pain.
[Dr. Jacob Flemming]
One question I had about those, many of these nerves that you're talking about are extremely superficial. One thing I was wondering about is a test injection is one thing, but with the ablation in particular, are there special considerations when you're ablating such a superficial target?
[Dr. Dan Nguyen]
Yes. You want to make sure that you take the longest path toward the nerve so that you can have the ablation portion of the needle underneath the skin because you don't want to cause a skin burn. That could happen if you're too superficial. Some of these nerves, yes, they do come superficial, but also there's a deep section to that. Like auriculotemporal, there is a deep portion that you can get to. You can see it relatively well with ultrasound. You stimulate and when you get there, you stimulate it with sensory. Typically, that gives you some sense that you're in the region and then you apply the heat for the ablative portion.
(8) Radiofrequency Ablation Complications: Anesthesia Dolorosa & How to Avoid It
[Dr. Jacob Flemming]
Excellent. On a similar note in terms of avoiding the complications, dreaded complication in this area is, particularly with the trigeminal ablation, is the anesthesia dolorosa. Could you tell our listeners a little bit about this phenomenon? What causes it? How do we avoid it?
[Dr. Dan Nguyen]
Yes. It's hard to predict if the patient will get that or the complication from after the effect. I haven't yet discovered if they get it pre-predictively from the front end if they get it. You discuss these complications, like say the V3, when you do the ablate, there is some portion of tongue numbness, mouth numbness. There's some of that peripheral, and you weigh the risk that with the patient, what pain they're having from the distribution, does it outweigh the potential complication of that? That's the discussion we have.
When you do that with the patient in the front end and give them the possibilities, and they'll weigh what they're living, and a lot of them are having really bad quality of life. To the point, like one of my patients can't even eat in front of the kids because their face is just electrical all the time. They're willing to take the negative effect of the complication from that. I haven't seen a lot of that, I don't know how to avoid it when it does come because you do know the front end is possible. Just having that discussion in the front end helps a lot if it does happen.
[Dr. Jacob Flemming]
Sure. Absolutely important to discuss the possibilities, even if remote. For our listeners who may not know about this clinical entity, it's one I only learned about recently. Anesthesia dolorosa, to my understanding, Dr. Nguyen, it's a rare complication of iatrogenic action with the Gasserian Ganglion, and it can, basically, because facial numbness, but with terrible pain as well.
At that point, that's a tough situation since we've used one of the Hail Mary options for pain in this region. It sounds like it's potentially using a larger ablation zone could make you more prone to doing that. There are pretty well-described techniques to the time and the energy for RF ablation, and these are more or less time-honored because it's been worked out over decades.
[Dr. Dan Nguyen]
Yes. Exactly. It is. It happens with the other technique, like you say, Gamma Knife. People, how specific it is described, people get the complication afterward as well. It's just one of those unfortunate parts that we can't predict from the front end if it's going to happen as well.
[Dr. Jacob Flemming]
It sounds like most of these patients with trigeminal neuralgia are benefiting quite a bit from these procedures.
[Dr. Dan Nguyen]
I think so. Knock on wood, I haven't had any serious complications thus far from this clinical offering thus far.
(9) Advice for Implementing Headache Interventions
[Dr. Jacob Flemming]
Excellent. It's, definitely, something, there's a huge need for it in most communities, and I think it's something that specialists with the skill set of interventional radiologists could definitely be offering. On that note, that's my last question for interventional radiologists who want to start offering headache interventions for their patients. What would be some words of advice for them, good first cases or areas to focus on and strategies to build referrals and early successes?
[Dr. Dan Nguyen]
Yes, well, that's a good question. I struggled with this four years ago as well, so this is very fresh on my mind how I did it. Not necessarily the only way or the right way, but I stepped back when on my drive here to Oklahoma from the East Coast, I thought, "How am I going to do this?" I've taken some business classes during my leadership time at the university and I learned this thing. I don't know, most people may have heard it, SWOT Analysis. It's Strength, Weakness, Opportunity, and Threats.
You take that approach first, you look at your strength. What do you have now that you would say is a strength? Do you have the personality, the facility, the people in the team that can do that? Do you have the skill to feel confident doing that? You want to make a certain list of that. Then I look at next, "What's my weakness? What am I weak in? Ultrasound? What am I weak in? Understanding anatomy?"
Just maybe review things I haven't seen in some time in this light. "What can I do to strengthen?" The idea here is to try to convert those weaknesses into strengths after you reassess and make alterations for additional courses, webinars, or sometimes develop some kind of mentor that can point you in direction to correct your weaknesses. Then I look at my opportunity, look around your practice area. Who's doing this thing that you can partner with? Who else is doing this thing in your area?
You can look at the websites for some of the practices around, see if they do that. Perhaps, like I spoke earlier, pay them a visit. Talk to them, give some grand rounds, develop personal relationships to open those opportunities up. Then, lastly, look at the threats. Is someone else doing better than we are? What we have to do to overcome that efficiency or supplies or which is more national reimbursement? What we used to do, now no longer we can't do because of reimbursement.
Another idea that I've had since then is, so instead of SWOT, S-W-O-T, it's now SWOTH. Add H to it is hunger. Hunger, I put it there because do not be complacent. You have to be open to new ideas, knowledge, and techniques in treating patients. You always want to improve your outcomes, so you have to stay hungry all the time. I go through a self-assessment every couple of months. What can I do to improve this practice and how to make it better?
In terms of what you say about some of the first cases you do, we're all familiar as radiologists, how to, with the myelogram and interpretation of it, there's a lot of new techniques that develop out there to diagnose and treat SIH. You will meet them at an ASSR meeting or ASNR meeting, but there's other dedicated headache meetings across the country that talk about that.
I think that's a good start because that's your baseline comfort zone. I think the other things you probably could start early with probably good success is occipital headache and cervicogenic headache. Those are relatively, a lot of them out there, and you can do some of that early on and get pretty good success from there.
[Dr. Jacob Flemming]
Thank you so much. A lot of great advice right there. Is there a way that our listeners, specialists who are interested in starting out this practice, can reach out to you for guidance in any way?
[Dr. Dan Nguyen]
Oh, you bet. I'm available anytime. You can find me on most of the social media and, certainly, I can send you my email afterward.
[Dr. Jacob Flemming]
Dr. Nguyen can be found on Twitter, @neuroradiology. I'm always really impressed that you managed to get the coveted neuroradiology handle. You must have gotten on pretty early on that.
[Dr. Dan Nguyen]
I did. I didn't even know what Twitter was. I just registered as such. I've had some people take that handle away from me, but it's just one of my things. I've had for like, oh, gosh, I think 12, 13 years, whatever that is.
[Dr. Jacob Flemming]
Yes. Tough to give that away, especially. Pretty great to be the king of Twitter neuroradiology. I definitely recommend our listeners follow Dr. Nguyen. He shares some great insightful cases, including some of the ones we've talked about. We haven't even talked about all the other spine work you do today and, of course, that's a big part of your practice as well. I think you've given our listeners, including me a lot of great information to think about in terms of the therapies that we can offer for these patients and how we can use our expertise and imaging and bring in the complimentary aspect of the detailed nervous anatomy, and the approaches that have been worked out by some other specialties. We can, definitely, bring that all in, integrating new techniques into our practices. I hope that a lot of our listeners are going to get a lot of value from the things we've discussed today. Are there any other things you'd like to talk about before we end?
[Dr. Dan Nguyen]
No. I just think this is an area where we can be fairly great contributors to the care of patients. I think it's another area that we are always going to learn more from each other, and I'm hoping to see more of this at a national level as well, including the ASSR.
[Dr. Jacob Flemming]
Absolutely agree with that. I can't wait to see that as well and look forward to seeing you and some of the others at some of these meetings coming up. With that, Dr. Nguyen, I want to thank you so much for your time today. Really enjoyed our conversation and can't wait for our listeners to hear it as well.
[Dr. Dan Nguyen]
Well, thank you again. Thank you for BackTable for this invitation. Thank you, Jake, for conducting a very fun conversation today.
Podcast Contributors
Dr. Dan Nguyen
Dr. Dan Nguyen is an interventional radiologist specializing in interventional pain management with Neuroradiology & Pain Solutions of Oklahoma.
Dr. Jacob Fleming
Dr. Jacob Fleming is a diagnostic radiology resident and future MSK interventional radiologist in Dallas, Texas.
Cite This Podcast
BackTable, LLC (Producer). (2023, September 6). Ep. 30 – Image-Guided Headache Interventions [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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