Radiofrequency Ablation for 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.
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[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.