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Radiofrequency Ablation for Trigeminal Neuralgia

Author Melissa Malena covers Radiofrequency Ablation for Trigeminal Neuralgia on BackTable MSK

Melissa Malena • Jul 4, 2024 • 40 hits

Trigeminal neuralgia can cause debilitating, treatment-resistant pain. However, when pharmacological treatment fails, there are still minimally invasive treatment options that can offer substantial pain relief. In this article, Dr. Dan Nguyen, former president of the American Society of Spine Radiology and expert in interventional headache treatments, shares his approach to radiofrequency ablation (RFA) for trigeminal neuralgia.

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

• Nerve block injections should be targeted toward the branch of the trigeminal nerve (V1, V2, V3) suspected to be overactive, and can double as a diagnostic tool while providing pain relief.

• Radiofrequency ablation (RFA) is a tried and true technique for targeted nerve treatment of trigeminal neuralgia, but requires additional considerations for superficial nerve targets.

• Anesthesia dolorosa is a rare complication of trigeminal ablation associated with chronic pain and numbness, particularly in areas of the mouth and tongue.

• Before any ablation procedure takes place, physicians should engage patients in an open dialogue about all the possible benefits and risks, no matter how remote, to foster informed decision making for patients.

Radiofrequency Ablation for Trigeminal Neuralgia

Table of Contents

(1) Treating Trigeminal Neuralgia with Radiofrequency Ablation

(2) Trigeminal Ablation Complications: Anesthesia Dolorosa

Treating Trigeminal Neuralgia with Radiofrequency Ablation

If pharmacologic therapy fails, minimally invasive treatment options are available for trigeminal neuralgia. Nerve block injections not only aid in diagnosis and visualization but also provide pain relief. Dr. Nguyen recommends targeting the suspected branch of the trigeminal nerve for test injections using ultrasound or CT imaging. For the V1 branch, approach the superficial supraorbital and supratrochlear areas with ultrasound guidance. For the V2 branch, use CT guidance to access the infraorbital region and the foramen rotundum. When addressing the V3 branch, approach the mental and alveolar nerves behind the angle of the jaw.

If the test injection provides relief, the next step is radiofrequency ablation (RFA). Dr. Nguyen highlights the area behind the maxillary sinus, where the sphenopalatine ganglia are located, as a significant target for RFA due to its extensive somatic and parasympathetic innervation. Although the sphenopalatine ganglia are relatively deep, superficial RFA targets require careful consideration. The needle should be advanced along the longest possible path to the targeted nerve to ensure that, once heat is applied, the needle tip does not cause any unintended burns outside the target area.

[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.

[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.

Listen to the Full Podcast

Image-Guided Headache Interventions with Dr. Dan Nguyen on the BackTable MSK Podcast)
Ep 30 Image-Guided Headache Interventions with Dr. Dan Nguyen
00:00 / 01:04

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Trigeminal Ablation Complications: Anesthesia Dolorosa

Anesthesia dolorosa is a rare but often feared complication of trigeminal ablation. It can develop after the procedure and manifests as persistent pain combined with numbness to touch, typically affecting parts of the mouth and tongue. Unfortunately, there are no known predictors or risk factors for anesthesia dolorosa. Dr. Nguyen emphasizes the importance of discussing potential risks with patients at the outset of treatment, even if the risk is minimal. Patients with trigeminal neuralgia often endure severe chronic electrical pain, so the possibility of anesthesia dolorosa may not always be a significant deterrent. Over his years of performing trigeminal ablation, Dr. Nguyen has not encountered any cases of adverse complications or anesthesia dolorosa.

[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, cause 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.

Podcast Contributors

Dr. Dan Nguyen discusses Image-Guided Headache Interventions on the BackTable 30 Podcast

Dr. Dan Nguyen

Dr. Dan Nguyen is an interventional radiologist specializing in interventional pain management with Neuroradiology & Pain Solutions of Oklahoma.

Dr. Jacob Fleming discusses Image-Guided Headache Interventions on the BackTable 30 Podcast

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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