NeuroVoices: Paul G. Mathew, MD, on Educating Clinical Community on Nerve Block Surgery Benefits

SAP Partner | <b>National Headache Foundation</b>

The assistant professor of neurology at Harvard Medical School provided insight on how to improve care for posttraumatic headache, as well as limitations and benefits to nerve block surgeries.

This is a 2-part interview. For part 1, click here.

Cranial neuralgias, common in patients with posttraumatic headache, may exacerbate underlying primary headache disorders by generating neuropathic symptoms such as lancinating pain and sensory dysesthesias. Treatment options for these neuralgias are different than those traditionally employed for posttraumatic headache without cranial neuralgias, which can include peripheral nerve blockade, neuropathic medications, and in some cases, peripheral nerve decompression surgery.

Despite the growing evidence of the benefits these surgeries bring, there is a lack of awareness among clinicians and patients to utilize these options, according to according to Paul Mathew, MD, DNBPAS, FAAN, FAHS. Mathew, an assistant professor of neurology at Harvard Medical School, has been a headache specialist for over a decade, with a passion for treating cranial neuralgias and expanding the research within the space.

He recently published a brief review of the literature and a retrospective report of 2 cases of posttraumatic headache with associated painful cranial neuralgias. One patient was diagnosed with auriculotemporal neuralgia, which responded well to auriculotemporal nerve block, while the second patient had supratrochlear neuralgia effectively treated with supratrochlear nerve block. Mathew sat down with NeurologyLive as part of another edition of NeuroVoices to get perspective on why these procedures are not well-streamlined. He talked about the lack of awareness, greatest unmet needs within this patient population, related research, and whether surgery stigmas play a role.

NeurologyLive: Are there a lot of patients who may be eligible for these types of procedures but are unaware of them?

Raising awareness among clinicians is important, but we can also harness the power of social media and patient discussion forms. I do have patients that specifically have come to me and said they were referred through Facebook. Attacking it from both angles and trying to educate clinicians as well as patients is a good strategy. Awareness on both sides strengthens that partnership and the opportunity to education people so that they may seek the proper diagnosis and adequate treatment for it.

What are the benefits to these types of procedures?

These nerve blocks are quick, in-office procedures. Sometimes afterward people feel a little lightheaded or dizzy. They may need to lay down for 15 minutes or a half hour and then they usually feel fine. If I’m doing both sides, I may suggest the patient have a ride to the office, but otherwise these are quick and easy to do. Coverage can vary from state to state, which may be a limiting factor, but the good thing is the fantastic risk-to-benefit ratio. There’s very little risk from injecting some anesthetic in this subcutaneous space and into the muscle and fascia area where these nerves run. You can tell from the data that the benefits are enormous. In many of my patients who receive both onabotulinumtoxinA for their migraines as well as nerve blocks for their neuralgias, it’s not uncommon for them to see me 4 times a year for their onabotulinumtoxinA injections but call me maybe once or twice a year to say that stabbing pain is starting to return. That will usually take care of it nicely.

What is the greatest unmet need for this specific patient population?

Like I mentioned, awareness it the biggest thing. I’m glad that more clinicians are realizing that this is important. Recently, I was invited to write a chapter that detailed how common these neuralgias are and the techniques for performing large volume injections. I’m in the process of writing the chapter in WOLFF, which is sort of the premiere textbook for headache disorders. I’m hoping that once things are referenced, the frequency of them, and how they can be effectively treated in these well-recognized textbooks, that it will raise the bar among clinicians. Maybe they will keep more of an ear and eye out for these comorbid diagnoses that oftentimes if untreated, will just exacerbate the overall pain levels of our patients.

Are there other types of related research that interest you?

I did do MRI studies in patients with bonafide occipital neuralgia doing fine cuts through the skull base region in the upper cervical routes. We unfortunately did not find any particular signal in terms of, "Yes, this person had occipital neuralgia. Yes, they’ll respond to nerve blocks." That unfortunately, was not all that satisfying. We did that for 6 patients and didn’t find much of anything. Larger studies may pan out and demonstrate that yes, these are imaging findings that are suggestive of candidacy in terms of nerve blocks, but ours was unfortunately negative.

The analogy I give to many patients is like having an electrical problem in the house. You can take all the pictures you want of both the outside and inside of the house, but unfortunately, it’s not going to show you the short circuit that’s causing the electrical problems. The other area of interest is for some of my refractory patients. They do a nerve block, get relief for days or weeks but not long enough to suggest doing this repeatedly. I have referred some of these patients for nerve decompression surgery with good results. Nerve decompression surgery is a good option for people who have refractory cranial neuralgias that do not respond to large volume blocks.

These surgeries have gotten a name because early on, some of our plastic surgery colleagues were performing these surgeries on patients who have garden variety migraine, where there’s no focal compression of any nerves causing this kind of lancinating neuralgia form of pain. Obviously, if you go in and decompress a nerve that doesn’t need decompressing, you’re probably not going to have a very good result. Sometimes, surgically altering the anatomy of someone who didn’t have any problems can create problems such as itching in the distribution of the nerve as well as sometimes worsening of the pain. Neurologists and headache specialists need to keep an open mind about surgical options in these refractory cases, but it certainly should not be a knee-jerk response for people with cranial neuralgias. I don’t think it should be considered for patients who have garden variety migraine, where there is no focal neuralgia component.

Do migraine stigmas hold patients back from getting these types of surgeries?

I don’t think there’s a stigma about the surgery per se. On the other hand, many patients will hear that a surgery can cure them, and, in that case, they will eagerly have the surgery without understanding the risks and benefits of it. Like all of medicine, nonsurgical positions such as neurologists and headache specialists need to do a good job of making the diagnosis, screening patients, and then appropriately referring people for surgical interventions when its appropriate. Performing these types of nerve decompression surgeries on people with garden variety migraine is irresponsible, and both positions should work closely with plastic surgery colleagues as well.

I have a good relationship with a colleague at Mass General and just about every patient I’ve sent him has had good outcome. None of them had just migraine. Nearly all of them have occipital neuralgia and 2 of them had suborbital neuralgia with decompression. Years later, they still do not have that lancinating, stabbing pain. I just saw the gentleman that was referenced in my piece. This is a man who’s in his 60s and while he was in Vietnam was thrown off a tower due to an explosion, fell 20 feet and suffered a head injury. For decades, in addition to migraineous and posttraumatic headaches, he had this stabbing, debilitating pain in the right temple. During his second visit with me, we did an auricular temporal nerve block. For nearly 2 years, he had been pain-free in terms of that stabbing pain. He has a headache a couple of days a month and he hasn’t needed to use a triptan in several months. That pain he’s been suffering with for decades is now gone. His migraine frequency has improved significantly because this trigger is now eliminated. All that from an injection that takes less than a minute to do in clinic.

Transcript edited for clarity. For additional segments of NeuroVoices, click here.