Apr 29, 2022

Interviewer: Severe, sudden, and sometimes debilitating face pain is a symptom of a disease called trigeminal neuralgia and some people suffer with the condition and don't even realize that's what they have. Or maybe it was misdiagnosed as something else so they can't get treatment.

Dr. Shervin Rahimpour is a neurosurgeon who specializes in the surgical treatment of trigeminal neuralgia, and he's going to help us understand how to come to that diagnosis. So first of all, you tell me it's a poorly diagnosed disease. What exactly do you mean by that?

Dr. Rahimpour: Often this pain is distributed around the cheek and jaw area. And so it's natural for patients to think that this is likely a result of their dental health. And so they often seek treatment through a dentist, usually, you know, undergo a tooth extraction or something like that, and that pain persists. So that's often why this is poorly diagnosed is because it overlaps with other common issues like having tooth pain.

Interviewer: Yeah. And I think a lot of us think well, the pain is here, this must be the source of the pain. It's in my mouth or my cheek, it must be the source. But that's not the case with this disease. Where does the pain originate from?

Dr. Rahimpour: The trigeminal nerve, which is one of the 12 cranial nerves that we have, supplies, amongst other things, the sensation that we feel over our face. So there are two nerves, one for each side. Each nerve supplies the sensation to that half of the face. And the nerve has three divisions associated with it. There's one that kind of overlays the forehead and around the eye. The other division is around the cheek area, and then a third division encompasses the jaw. And so most commonly, the pain is likely to affect those bottom two divisions, which is around the cheek and the jaw area, and that's where this overlap comes with potentially pain coming from your teeth.

Interviewer: And somebody goes to the dentist, they have an extraction done and that doesn't solve anything. Do they try to get a diagnosis beyond that, or do most people just give up or do you know?

Dr. Rahimpour: Yeah, I should add that sometimes it can be your teeth. So it is worth having that evaluation done by your dentist. But eventually, this pain syndrome is referred either to a pain specialist or even a neurologist. Those are the folks that typically end up diagnosing this as trigeminal neuralgia-type pain.

Interviewer: Explain some of the common symptoms that people might experience.

Dr. Rahimpour: Yeah, absolutely. So again, this pain used to be . . . this disease used to be known as suicide disease because it was such a horrible pain for patients to experience. And it's often a severe electric type jolt or stabbing pain involving one or more of the divisions of the trigeminal nerve of the face. It's often set off by very relatively innocuous stimuli. What I mean by that is anything as simple as just a gust of wind, or talking or brushing your teeth, or having water hit your face when you're taking a shower. These are kind of the very, very basic and innocuous things that can trigger that type of pain.

Interviewer: And what's going on with the nerves that is causing this pain?

Dr. Rahimpour: The vast majority of cases are thought to be caused by a vessel sitting on the nerve root as it enters into the brainstem. And so what this vessel causes is damage over a period of time that ends up injuring the insulation around the nerve known as myelin. And then this can result in sort of aberrant firing of the nerve.

Interviewer: So it's rubbing against there, damaging the insulation every time your heart beats.

Dr. Rahimpour: That's exactly right.

Interviewer: It's damaging the . . . Okay.

Dr. Rahimpour: So the thought is that if we can remove or transpose this vessel from the nerve root . . .

Interviewer: Yeah, get it away from there.

Dr. Rahimpour: Get it away from there, that could potentially allow the nerve to heal and prevent some of this aberrant firing.

Interviewer: And if a patient has this type of pain, they would go to their primary care physician first likely. What would that workup look like?

Dr. Rahimpour: Typically, the patient has these classic types of symptoms or the stabbing electric type pains of the facial region, again, involving either one or more divisions of the trigeminal nerve. And we often ask patients, you know, "How is this pain brought about?" If it's something, again, wind, chewing, talking, anything like that, that's pretty consistent with trigeminal neuralgia. The pain also again persists to seconds to potentially minutes, and so that's another signature or hallmark of the disease. And we often look for patients that, you know, typically we find that this disease occurs more often in the older population. So the incidence kind of climbs as age goes up. But this can also be a result of some other secondary processes. Certainly, it can range anything from facial trauma and include other secondary causes like multiple sclerosis.

Interviewer: At what point should a person consider consulting with a physician who specializes in trigeminal neuralgia?

Dr. Rahimpour: I think early on it's best to have the medical therapy be optimized. So a lot of the medications we use for this type of pain are actually anticonvulsants used in epilepsy. The reason why is because, similar to epilepsy, the nerve can act on its own and fire. And so the idea is can we stabilize this nerve so that it prevents it from firing, the same way that we try for epilepsy. Those types of medications are started, they're increased to a therapeutic level and then the patient is evaluated to see if this treats their pain. Again, the vast majority of patients respond to these medications, something upwards of 90%, but half of those patients end up having unwanted drug side effects. And then, of course, there's a 10% that did not respond to the medication at all.

Interviewer: Yeah. And this medication, is it kind of a dialing-in process, you've kind of got to figure out the sweet spot for everybody?

Dr. Rahimpour: Yeah, I would say that most anticonvulsants are started at a low dose and gradually titrated up.

Interviewer: And for the individual that is not responding to medication, or the side effects are just so terrible that it's really impacting the quality of life, and that's where the microvascular decompression procedure comes in. That's what you're doing there.

Dr. Rahimpour: That's exactly right. So for patients that aren't responding to the medication, if they've had an MRI scan that shows that potentially there might be a vessel there pushing on the nerve, that's where microvascular decompression can play a role.

Interviewer: What about for patients where they have the condition, and it's not pressing against that nerve? That's possible, right?

Dr. Rahimpour: Patients where we don't necessarily see a blood vessel pushing on the nerve, or they might not necessarily be a good operative candidate, we can offer other minimally invasive approaches. Those approaches include percutaneous rhizotomies. The premise there is that we with a needle go to the base of this nerve, known as the trigeminal ganglion, and we try to damage that nerve to sort of disrupt the pain signal. The other option is using radiation in the same way that folks use it for tumors to try to focus the radiation and try to damage the nerve again, to stop this pain signaling.

Interviewer: Are these other last two procedures, are they an alternative to somebody getting a microvascular decompression?

Dr. Rahimpour: They are alternatives, but I should add that they're not as efficacious. So when we do find patients are good candidates for microvascular decompression, we try to advocate for that as it gives us the best chance for pain freedom.

Interviewer: After somebody has the microvascular decompression, what is the success rate that that actually takes care of the pain?

Dr. Rahimpour: We expect that patients often have immediate pain relief after surgery, especially if we do find a blood vessel that's compressing the nerve. Historically, 70% to 80% of patients are still pain-free at five years.

Interviewer: And the other 20%?

Dr. Rahimpour: Pain can reoccur. And if that's the case, we can always revisit other possible interventions, including some of the percutaneous and radiosurgery techniques that I mentioned.

Interviewer: For the patients who get the microvascular decompression, what's the satisfaction rate among those patients? I hear this could be life-changing for some people.

Dr. Rahimpour: Absolutely. So again, this is a very debilitating disease. I mean, you can imagine if it's affecting the way you eat, and the way you conduct yourself throughout your day-to-day in anticipation of a sudden pain strike, being pain-free means everything. And so when patients are pain-free again, where we expect that to be the case in the vast, vast majority of times after microvascular decompression, this is absolutely life-changing.

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