Sammi: Good evening everybody and welcome to this evening’s Facing the Problem – Trigeminal Neuralgia and sinus disease in general practice. My name is Samantha and I am your host for this evening. Before we jump in, I would like to make an Acknowledgement of Country. We recognise the traditional custodians of the land and sea on which we live and work and we pay our respects to Elders past, present and emerging.
So I would now like to introduce our presenters for this evening. We are joined by Professor Marcus Stoodley and Professor Ray Sacks. Professor Stoodley is an Academic Neurosurgeon whose clinical sub-speciality qualification is in neurovascular surgery. In addition to managing aneurysms and vascular malformations, he is a leader in cerebral bypass surgery and is recognised internationally for clinical management of Chiari malformation, syringomyelia and spinal cord tumours.
Professor Ray Sacks has just retired as head of discipline and ENT surgery at Macquarie University Hospital after ten years in the position. He is still head of ENT at Sydney University and has published over 120 peer-reviewed manuscripts, 25 book chapters and the first text book on endoscopic orbital surgery. He is a past President of the Australian Rhinology Society, and was the Chief Examiner in ENT for the Royal Australasian College of Surgeons, and has been the invited speaker at sinus conferences and workshops in 35 countries on six continents. So, welcome Ray and Marcus, thank you for joining us.
Ray: Thank you for having us.
Sammi: No worries. And I would like to introduce also, Dr Tim Senior who will be our facilitator for this evening. So, Tim is a GP at Thurawal Aboriginal Corporation in South Western Sydney. Tim is also an RACGP medical advisor for the National Faculty of Aboriginal and Torres Strait Islander Health, and a Senior Lecturer in General Practice and Indigenous Health at UWS. So welcome Tim and thank you for joining us.
Tim: Thank you very much. It is good to be with you all this evening. So, these are the learning outcomes for tonight, which is the educational speak for what we hope to achieve this evening, so by the end of this activity, we should be able to identify the clinical features of trigeminal neuralgia, hemifacial spasm and glossopharyngeal neuralgia. We should be able to recognise the cause of trigeminal neuralgia and other cranial nerve hyperfunction disorders. List the treatment options for cranial nerve hyperfunction. Identify the pathophysiology of sinus disease and know the optimal management and rationale for chronic rhinosinusitis. So we have got a lot to get through tonight. So without further ado, we will move onto Professor Stoodley. If you do have questions, feel free to put them in the question box. We may not get to them all tonight depending on timing, but we will see how we go.
Sammi: We have actually got Ray up first.
Tim: Oh, I am so sorry.
Ray: That is alright, Tim. Thank you very much, we can swap our talks… So Tim, I am going to kick off and I am going to talk to you about the current understanding of chronic rhinosinusitis, and essentially what I am not going to be talking about tonight is rhinitis. And rhinitis is a very, very common presentation to general practice, and is commonly misdiagnosed as chronic rhinosinusitis. So I really want to specifically talk about chronic rhinosinusitis and just highlight the disease and its management. There are lots of factors that affect the outcomes of chronic sinus disease and I am going to touch on many of these factors and how as general practitioners, you can better your approach and your outcomes for these patients. So let us just look at patient factors. Well, if you have got a patient who has had multiple prior sinus surgeries, who has had multiple surgeries in the past, the likelihood is that they are a true sinus disease patient. Often they might not have started off as a true sinus disease patient and had a trauma from surgical intervention and have had iatrogenic sinus disease. But when you have somebody who has had multiple operations, that is considered a very poor prognostic factor for long term management. If there is a systemic disease particularly things like asthma, we talk about the ASA Triad which is asthma, salicylate sensitivity and nasal polyposis. Things like diabetes, the autoimmune conditions, cystic fibrosis. In fact any condition that will lead to abnormalities in mucocillary clearance and inability of the sinuses to function normally have got poor prognostic factors associated with them. And there is good evidence that smoking, allergy and also depression are associated with poorer outcomes. Depression, particularly in those patients where pain and headache is their major symptom. And often a patient walks into the GP practice and their major problem is facial pain and the GP palpates their sinuses still trying to work out why. They palpate their sinuses and they say they are tender and they diagnose them as chronic rhinosinusitis. The truth of the matter is, their chronic sinus disease very, very rarely has pain as one of its features. And in fact, the diagnostic criteria for chronic sinus disease in the conglomeration of the symptoms of nasal obstruction, post-nasal drip, anterior rhinorrhoea, loss of sense of smell, nasal congestion, together with either endoscopic or radiologic evidence of sinus mucosal disease. So if you do not have those latter two objective findings you actually cannot make the diagnosis of chronic rhinosinusitis on the basis of history alone.
When we talk about chronic rhinosinusitis, we essentially are talking mainly about polyp disease, because that is how it primarily presents. In much the same way as asthma affects the lower respiratory tract, causes bronchospasm, when you have inflammation of the upper respiratory tract we tend to get polyp formation. And there is a whole lot of polyp disease factors which affect our ultimate outcome. And I am not going to go through those in great detail with you today, other than putting a list up there so that we show you what we as ENT surgeons look for when we do assess a patient polyp.
So, I am going to take you back to this concept of the unified airway, because it is really, really important that you do not think of the sinuses as just a simple structure. They are very, very complex. It is completely inappropriate to apply simple concepts such as, he has a blocked sinus or unblocked sinus to the sinus, because it is really, really so much more than that. And there are also multiple pathologies of pure polyp in chronic rhinosinusitis. For example, this patient here who has got extensive polyp in their nose, on CT scan one can see that they have got very severe allergic fungal sinusitis. They have got fungal disease filling their sinuses and the disease is actually the host’s response to the presence of fungus with the development of polyps. And this is very different from the ears and the polyp that you see in the nose where there are just these simple inflammatory polyps on both sides of the nose. And again, very different to this patient here who has a unilateral right-sided maxillary antral mycetoma. One can clearly see these hyperdensities here, and that is always the diagnostic clue for the presence of fungus in the sinus. So this is a simple mycetoma.
When somebody has a pure obstructed sinus such as this patient here, you will see that all the other sinuses are absolutely pristine and healthy. Incidentally you see a little bit of mucosal thickening in the floor of the maxillary antrum here. It is of no relevance whatsoever. These are often odontogenic in origin and really if someone has got a mucus retention cyst in the maxillary antrum, it does not indicate or intimate disease in shape or form and should be absolutely ignored. It is like having a skin tag. But if you have somebody who has got an obstruction here, relieving the obstruction will obviously reverse the sinus disease.
But what we most commonly see and what you see in general practice is this type of picture, where the radiologist has reported a pansinusitis because there is involvement of all the sinuses and one can see the polyps hanging down in the nose here. One can see disease within the maxillary and the ethmoid cavities, but we can also see areas here of completely clean, healthy mucosa. And so this is not a ventilation problem. This is not a problem of an obstructed sinus. So we really need to think beyond a plumbing issue when we talk about sinus disease. And if we look over the years, if you fail to acknowledge the evolution of our understanding of sinus disease, and think of the sinuses and their pathology just in terms of plumbing, then you are doomed to failure in terms of long term management. And if you think of them, if you think of inflammation and mucostasis as being the major pathophysiological process and medical and surgical treatment is really a tool to try and break this process, you are bound for success. But it is important that you look at research and clinical practice and you make sure that you are following the pathway with harmony and not with a diverge.
So I am going to take you back a few years, because many of you were taught when you were at medical school, that sinusitis and nasal polyps were all a problem of infection and obstruction and require antibiotics and surgery to relieve the obstruction. And that was really the rule in the 70s and 80s. And then suddenly with electron microscopy and advancements in research in sinus disease, we realise that nasal polyposis has nothing to do with infection. There is no problem with bacteria and bugs. This is a problem of inflammation, and we thought the rest of rhinosinusitis was infection and obstruction. And it is only really in the last 20 years that we understand that this picture is very, very mixed and it is probably a combination of all of these factors with inflammation being a major factor in the production of sinus disease. And that is going to have significant implication on how we diagnose and manage it.
So when I look at somebody with inflammatory sinus disease, my real goals are to try and create a single neo-sinus cavity because this allows for easy removal of inflammatory hyper-secretory mucus. You all know that you put patients onto a saline irrigation bottle and they tell you they feel much better. And what that is effectively doing is washing out the allergen, washing out mucus that is stimulating an inflammatory response. So if they have got a large cavity, it is so much more effective. It also allows us to have topical access which is where the philosophy in the management of chronic sinusitis has changed so much in the last decade. We also obviously reduce the mucosal surface area and thus an inflammatory load reduction throughout, and we also promote this whole concept of mass mucocillary action and avoid secondary mucus trapping in the little nooks and crannies within the sinuses.
And so we ask ourselves, is delivery to all post-ESS cavities the same? And I have had lots of general practitioners say to me, oh my patient had a VESS, they were really no better off. Well these are all pictures of patients who have had endoscopic sinus surgical procedures. And there is no way that we can compare this type of picture in A who has had just some dilatation of an ostium to this patient in B who has had a big hole made in the posterior fontanelle on the maxillary sinus which is far from the natural ostium to this kind of complete neo-sinus cavity which we as ENT surgeons and certainly as rhinologists, strive to perform in our patients. And it was Richard Harvey who discussed, who published this paper looking at different delivery techniques and different surgical states. And what he actually showed was that in patients who use nasal sprays without surgery, you may as well, it would almost be like giving somebody with asthma a steroid mouth guard. It just does not get to where it needs to get. And so it is only this group here, the people who have actually had decent surgery and using decent volume of irrigation and medication who get good results.
So how do you go about predicting which patients are inflammatory? I am going to take you through Sally Wenzel’s diagram. The respiratory physicians have a huge advantage over us ENT surgeons in that there is a lot more financial backing and asthma research than there is in sinus research. And so we adapt a lot of our stuff from the respiratory literature. And this is looking at the basis of asthma and the evolution to how to manage asthma. And there are certain endotypic differences. But there are a lot of significant similarities. So I like to look at this first group here. The allergic group. The childhood and young adult group. These are the patients who have a strong association with asthma. They have a strong association with rhinitis, and this is probably much more related to common allergen exposure. These are the patients who present with early onset nasal obstruction, congestion. You can often see the rhinitis. They often have that darkening under the eyes, they have rhinorrhoea, and they often have rhino-conjunctivitis with itching of their eyes and watering of their eyes as well. And it is this group of patients who we really need to diagnose. And the easiest way of diagnosing them is look in the nose. Now we have the advantage of endoscopes, but you have an otoscope in your rooms. And if you just put the normal end of your otoscope and put it in the patient’s nose, you can actually see their middle turbinate. What you will see when you look in their nose, you will see the septum medially, you will see the inferior turbinate which is inferolaterally, and just above it you see the middle turbinate. And when you see this kind of polypoidal change and this mucosal oedema, over the middle turbinate. It is almost considered a diagnostic marker of inhalant allergy, because that is where all the allergens that have been inhaled hit. So the grasses, pollens, dust mite, cockroach. All the allergens that people inhale typically hit the inferior and the middle turbinate and cause this degree of congestion and mucosal oedema.
And we actually did a paper looking at middle turbinate oedema as a diagnostic marker, and we showed that it had a very significant positive predictor value when you had this oedema over the middle turbinate, and that the odds ratio, the likelihood ratio of having an allergic cause of the problem was extremely high. So you look into their nose and you see this and I realise that you see this in isolated pictures, I am showing a video here, but one can classically see nasal polyps when you look in the nose. But these nasal polyps are all arising from the middle turbinate and the rest of the nose is absolutely clear. This is inhalant allergy.
And we have defined and described a new sub-type of condition which is really important for you as general practitioners to know. What you see here looks like simple nasal polyps. But when you look at the CT scan what you can see is there is severe nasal polyposis all within the nasal cavity. But if you look at the sinuses, these sinuses are actually beautiful. As I said, the thickening in the floor of the maxillary antrum, about as much relevance as saying the patient had dark hair. It is of no relevance whatsoever. It is not sinus disease. This is a central compartment atopic disease. And you are going to hear more and more about this in the future. And this is best managed with intra-nasal therapy, with combinations of steroids and antihistamines. This is the most appropriate and best way of managing these patients, together with an allergist and immunological identification of allergen and immunotherapy is considered appropriate.
And this is a typical example of central compartment atopic disease, where you have got normal sinus mucosa and you have got a bit of obstruction because of the polyps within the nasal cavity. These are not sinus surgical patients. These are medical allergic patients. So let us go back to Sally Wenzel’s diagram. This was our childhood and young adult allergic disease. As we move onto adult onset, this is what we term eosinophilic rhinosinusitis. This often has a strong association with asthma and they typically have eosinophilic findings both on their blood and on tissue eosinophilia. And these are the patients that form the large bulk of our chronic sinus patients. And the St. Vincent’s Group established this histopathology report form which is now utilised throughout Australia and pretty much internationally. It was published by our research group here, but essentially what we can get now is a report that does not say the patient has chronic sinusitis. We knew that before we took the biopsy. What it shows us is that the patient has a significantly high eosinophil count. Somebody who has got significant basement membrane thickening and sub-epithelia oedema, and some people who have got Charcot-Leyden crystals and elements of fungal infection. And this gives us a much better idea of how to manage these patients long term.
So we have looked at serum eosinophilia. Is this a good alternative to tissue eosinophilia? And what we found was that there is a very, very good positive, predictive value, indictor, if it is positive for high serum eosinophilia, but not if it is negative. It has got a low negative predictor factor. Serum IgE was really not a predictor at all and it does not have any role in terms of establishing whether the patient is eosinophilic or not. And this is your typical patient with severe eosinophilic disease. Complete opacification of the sinuses, severe polyps. And one can see these bearded mucsun which is very, very classic of eosinophilic disease. This is a very, very classic eosinophilic chronic rhinosinusitis. And when we have these patients, we want to get them on to steroid, but we want to get the steroid up here and over there, we want to get the steroid into the frontal. We want to get the steroid into the sphenoid. And nasal sprays are exactly that. They are nasal sprays. They have excellent distribution in the nose and are fantastic for management of allergic rhinitis. They have no role whatsoever in the management of sinus disease, because I know you cannot read these, I do not intend you to read these, there are multiple studies, that is all the point I am trying to make here. There are multiple, multiple RCTs et cetera that show that the impact of the vast, the impact of the device and the surgical state are the two most important factors when it comes to management. Because where does our anti-inflammatory therapy need to go? This is your typical allergic rhinitis. This is patients who just have turbinate oedema. Who just have congestion of the inferior turbinate. Where we are talking about is out here in the sinuses. That is where we need to get our medical therapy. And we have a very, very good way of getting it. It is called steroid. It gets in there very, very effectively. The problem is when you are using systemic prednisone you are getting a great dose into the sinuses but you are also getting a fantastic dose into the bone and the muscles and the liver and the kidneys and the brain and the breasts and the genitalia and all the other organs. So what you really, really want to do is get our anti-inflammatory therapy directly into the sinus cavity and that is why we need a good surgical state and a good high volume irrigation with steroid in it in order to get there.
And myself and Richard Harvey and Larry Kalish and a couple of other ENT surgeons around, we did a randomised control trial and I am not going to take you through the whole trial, but basically what we really looked at were two groups of patients. All of these patients had full-house endoscopic sinus clearances. So they all had the exact same surgical approach. And then, we had two different interventions. One, who had placebo in the wash bottle and active ingredient in the spray bottle, and one who had active ingredient in the spray bottle and placebo in the irrigation bottle. And we compared them over a prolonged period of time. They all had a minimum of one year follow up, and we compared them using a whole lot of different techniques. We looked at all the patient outcomes. We looked at radiology. We looked at endoscopic scores. We looked at other factors and we looked at systemic steroid and antibiotic use. And what did we find? We found that our baseline demographics for both groups were absolutely identical. The disease burden and all symptoms absolutely identical. But when we actually looked at all our patients, we saw that all actually did very, very well which basically means that the surgery does work, and that irrigation with saline does work. And so if that is all your patients do, it does make a difference. But, when you look at independent symptoms such as the change in blockage of their nose, their endoscopy and their radiology scores, there are significant benefits over using topical steroid as opposed to a nasal steroid spray. And if you look at this graph, one can see the blue are the patients on Mometasone spray. You can see that everybody actually did reasonably well, but we did have failures on the Mometasone spray, whereas we did not have any failures in the Mometasone irrigation bottle. So essentially, we know that we can get a much better result in these patients with good surgery and long-term intranasal irrigation therapy with steroid. This was evident on endoscopy and evident on imaging as well. And so our whole aim is to take this patient here and make, this is the same patient, turn them into this patient here which had a good surgical approach and is now utilising the Pulmicort irrigation therapy with irregularity. And I say to this patient, they have asthma of their nose, and if they stop their therapy they are going to have an acute flare-up.
So finally, just for the last few slides I am going to take you back to Sally Wenzel’s diagram and show you this group of non-eosinophilic chronic rhinosinusitis. This is the much older group. This is the non-TH2 driven patients. So here is a good case. This is a 50-year-old female who has extensive polyposis, had a very good operation by a good ENT surgeon, and had a complete wide-open ESS and goes on a steroid irrigations, is really very, very good and reliable with the steroid irrigations and at three months looks like this. And so we have got to do something better for this woman. So when we look at her clinical mojo we see she is middle aged, she is female, she is overweight. She has got a low IgE and that is how we always define a neutrophilic non-eosinophilic chronic rhinosinusitis. But we need to be much more scientific and that is where this whole concept of tissue histopathology profiling comes in. And what you can see in this patient is a very low eosinophil count and so when we put her on macrolides, this is predominantly neutrophils. When we put her on macrolides one can clearly see that the polyps and the disease just completely melt away. This lady now has a nice wide open cavity and a healthy sinus and she is now completely asymptomatic. You can see the carotid artery nicely over here, optic nerve there, skull base. Nice, good case study for the neutrophilic. It has to play out sorry. This is looking at the other side now and again there you can see the nice wide open skull base.
So what are macrolide responders? These are patients who more than three months following on macrolide therapy have completely normal or near-normal mucosa on endoscopy. When we looked at who were our macrolide responders and we basically found that people who have very low serum eosinophil, very low tissue eosinophil and who have no squamous metaplasia. Those are the group of patients, because squamous metaplasia indicates that there is tissue remodelling. Those are the patients who really, really respond well to macrolide therapy.
So now finally, if we go to our diagram our first group of people are the allergic patients. Those are the patients that you as GPs should all be managing with intranasal irrigations, saline irrigation to wash out allergen. Intranasal corticosteroid sprays, intranasal antihistamine sprays or combinations. The eosinophilic chronic rhinosinusitis patients, these are the patients who are best going to be managed with topical steroid irrigations in a post-surgical state. And the non-eosinophilic patients who are best going to be managed with long term macrolide therapy.
So in summary, this is how we start off seeing our patient and that is what we want to end off seeing our patient, a wide open common cavity. We can see the frontal. We can see the skull base. We can see the optic nerve. We can see the carotid artery. There is the medial wall of the orbit. And we know that our philosophical approach to the disease has changed significantly. We now need to use high-volume topical therapies together with medical therapy and that tissue profiling really does guide our postoperative treatment. I want you when you think of eosinophilic disease to think of asthma and to consider all these factors when prognosticating. And overall, we all failures so be realistic. Thank you very much.
Sammi: That is great, thanks so much Ray. Tim, did we have any questions come through?
Tim: Yes. There were two questions that we could probably go over quite quickly. One came through almost right at the start, and you did certainly cover some of this, around the Pulmicort respule rinses and just wondering about the dosage of that and how we educate patients on using them effectively.
Ray: Yes. So you can use, essentially we use 1 mg in 2 ml of the nebulising solution and it is used off label and they come in a box of 30 ampules and you take one ampule and you put it into a 240 ml wash bottle. There are a whole lot of wash bottles out there at the moment on the market. There are flow wash bottles, there is NeilMed, and there are Fess bottles. They are all essentially the same. What you do need to warn your patient is that when you mix the budesonide into the water, the water needs to warm to slightly hot and it also needs to have the saline bicarb buffer in it, otherwise it makes it very acidic and it actually stings them. So always tell them to get from the pharmacy a box of little saline bicarb sachets. They come with these rinse bottles, to fill the water up to the line and then add the sachet and then add the Pulmicort. They only need to do this, because as you know, once they are under control our maintenance dosage is probably about three or maybe four times a week at most, but initially we would have them on irrigations on a daily basis until we had their disease under good control. Does that answer the question?
Tim: I think it does. Thank you very much. Can people have symptoms from chronic decongestant usage or other medications?
Ray: Oh absolutely. So, again we are coming to rhinitis. And Tim might be very happy to come in another night and talk about rhinitis, but that is a subject all on its own. But rhinitis is rhinitis medicamentosa, unfortunately a not uncommon condition where patients have been using decongestive vasoconstrictive therapy for too long. And what effectively happens is that you vasoconstrict the vessels to the mucosa. So you do get a really good and immediate result but you also deplete the cilia on the mucosa of oxygenation with vasoconstriction and you get ciliary problems, you get rebound phenomena and you get a lot of crusting and ultimately you end up with rhinitis medicamentosa which almost mimics atrophic rhinitis and the patient is more blocked because of the crusting and the loss of a normal physiological function of the nose.
Tim: Excellent. We will book you for another talk on that. And just another question. These pictures that you had of the tissue profiling, they looked like they were from biopsies. There is question about whether they are from a nasal wash or from biopsy?
Ray: No those are all from biopsies. They are all from biopsies and nasal wash unfortunately does not give us the information that we need. So they are all from biopsies. Unfortunately that is out of the general practice realm but certainly the diagnosis is not.
Tim: Excellent. Thank you very much. And I think thank you for answering those. We will move on to Professor Marcus now who is going to talk to us about cranial nerve hyperfunction syndromes.
Sammi: Wonderful. Thanks very much Tim, and welcome Marcus.
Marcus: Thanks very much and welcome everybody. Thanks for joining us. It is a tough act to follow. I am sure you are all familiar with the cranial nerves and you probably, I am sure you are, very familiar with cranial nerve palsies, meaning dysfunction or hypo lack of function of the cranial nerves. But the syndromes that I will be talking about tonight are really the opposite of that, where the cranial nerve function is increased and that is really the underlying basis for these conditions.
So, if we go through the cranial nerves that are involved, the most common one that you will know about is trigeminal neuralgia. So that is increased functioning of the sensory part of the trigeminal nerve. So that is manifested as trigeminal nerve pain, but it is the same underlying problem that causes hemifacial spasm. So that is increased function of the facial nerve where the muscles of the face go into repetitive spasms. We will talk a little bit about that. There is also reason to think that some patients who present with tinnitus and vertigo actually have the same underlying pathology of the cranial nerve VIII that I will talk about in a minute in that the function of that cranial nerve is increased. Similarly, glossopharyngeal neuralgia which is much less common that trigeminal neuralgia but has a similar problem where pain affects the distribution of the glossopharyngeal nerve which is at the back of the pharynx, the posterior part of the tongue and also if we remember back to embryology, in part of the ear canal. So patients will present with ear pain, throat pain and tongue pain. Very similar in character to trigeminal neuralgia but much less common. And there is also evidence to suggest that some patients, and this is not very common, but some patients with what might otherwise be called essential hypertension where there is no clear underlying cause, are actually suffering from increased function of the vagus nerve that is causing the increase in their blood pressure. The hypertension and the tinnitus and the vertigo are probably less well accepted than the other cranial nerve hyperfunction syndrome so I will not talk much about those. I will talk a bit about the history because I think that is interesting and the underlying pathology of these syndromes which we think is common to all them and then I will talk about the clinical features particularly of trigeminal neuralgia, how we go about investigating them, and how we treat them.
So, if we think particularly about trigeminal neuralgia, that has been recognised for many centuries. So, it was actually described by Gelan and then also by Locke in the seventeenth century and again by Fothergill in the eighteenth century. And they were considered a mental or nervous disorder rather than a physical disorder. The actual underlying pathology was recognised by Walter Dandy one of the founding fathers of neurosurgery in 1925.
What is really interesting for neurosurgeons is that it seems that medical profession outside of neurosurgery has not really caught on to the idea of what the underlying pathology is. So, if you look at your medical school text books, they will describe trigeminal neuralgia as an idiopathic condition with no known underlying cause. But neurosurgeons would generally accept that we do know the cause. And the cause is, if we look at this diagram on the right, is basically a short circuiting of the axons in the nerve. And typically in trigeminal neuralgia and these other hyperfunction syndromes, the cause of that short circuiting is – just hang on a second – the idea is that the - I am just bringing up a pen to draw with – okay so, the idea is that compression or pathology of the nerve of the axons that causes demyelination allows signals to short circuit across the nerve fibres. And in the case of trigeminal neuralgia if there is that sort of demyelination, a small sensory stimulus to the face then basically ends up causing firing off of all the axons in the trigeminal nerve and that causes severe pain. The cause of the demyelination is most commonly pressure from an artery. But it can be multiple sclerosis so patients with MS who have demyelinating plaque in the trigeminal nerve will have very typical trigeminal neuralgia because of the short circuiting in the nerve. It can also be caused by other compressive lesions such as tumours, particularly meningioma and vascular malformations and sometimes a bony spur that comes of the petrous bone. So, the vascular compression is the most common but it can occur with other lesions.
So, this is an intra-operative photograph demonstrating and I will just bring up the pen again. So this is in this case, the facial nerve running across here. This is a loop of artery which in this case will most likely be the anterior inferior cerebellar artery. But you can appreciate that there is a loop of artery here and that the facial nerve is kind of kinked by the pressure from the artery. Now of course what happens is as we get older, is this type of loop of an artery gradually gets longer, so arteries become more tortuous as we get older, and so it is just kind of a bad luck thing, that somebodies artery is placed in such a way that as the loop lengthens and becomes more tortuous, it causes more compression of the nerve. And that is why these conditions affect people more commonly in older age groups.
So if I just go through descriptions of the different types of – I am going to focus on these three types of cranial nerve hyperfunctions, and that is the fifth nerve, the seventh nerve and the glossopharyngeal nerve because these are the most widely accepted characterisations. This is the formal definition of trigeminal neuralgia from the international headache society and I will not read that out, but it is very typical for pain to be commonly brought on by what might otherwise be trivial stimuli. So particularly anything that touches the face, cleaning teeth in particular, talking. Patients will often complain that if they are driving and the window is open, the wind on their face stimulates their pain. The pain comes on like an electric shock. So it is very sudden onset and has intermittent electric shock type character. It is very typical though for patients who present with trigeminal neuralgia to have periods of remission. So it may even go away for several years. But almost invariably once a patient has developed trigeminal neuralgia then the older they get, the more severe it gets and that is generally because the arteries become more tortuous and there is more pressure on the nerves. It is common for patients with trigeminal neuralgia to not suffer from the pain once they have fallen asleep. So, we think this is something to do with the horizontal position just slightly altering the compression of the nerve from the artery and that is just one of the common features. It can be bilateral but that is very rare and it has to really be in the distribution of the trigeminal nerve, so in the first, second, third division or combinations of those. The first and second would be the most common but it can also affect the third division.
So it is similar as I have said here, the pain tends to get worse and then over time, rather than being intermittent with electric shock type character, it can change to a more constant and maybe even a burning type pain, and that is classified as a type 2, trigeminal neuralgia and one that is more difficult to treat.
So I will just go to glossopharyngeal neuralgia. It is very similar to trigeminal neuralgia. It is really just that the distribution of the pain is in the area supplied by the glossopharyngeal nerve, the sensory component of the glossopharyngeal nerve which is the back of the pharynx, the posterior third of the tongue and part of the external ear canal which you remember from embryology has parts of multiple cranial nerves. And this is often brought on by people swallowing, chewing and is of similar kind of severity to trigeminal neuralgia. These pains can become so severe that patients will contemplate and even commit suicide because of the severity of the pain. And before effective treatments for trigeminal neuralgia were developed many of these patients committed suicide because of the severity of the pain. One of the things that I will always tell patients when I see them, because generally I see them in the outpatient clinic and the pain is not necessarily very severe, is for them to recognise or understand that sometimes the pain can reach a crescendo where it is so bad that they are unable to swallow and so it can become an emergency if they cannot drink, swallow and sometimes in severe cases cannot even swallow their own saliva because it stimulates the pain too much. Those patients should understand that they can present for emergency treatment, because otherwise they are in real trouble.
Now hemifacial spasm is as I say similar pathology where there is demyelination and short circuiting of the facial nerve, but because this is not a sensory nerve, the manifestation is really by electrical signals travelling the other way, so that even small amounts of discharge in the fibres of the facial nerve result in contraction of the whole muscle groups supplied by the facial nerve. Typically this starts with contractions around the eye, so it will often appear as though the patient is blinking which reminds me of a doctor patient I treated who presented because the patients thought she was winking at them all the time, and so she was very keen to have treatment. So it is not a painful condition but is a very disabling condition because of the social importance obviously of the facial musculature function. As patients get older the muscles affected spread from around the eye to involve the whole face and can become very forceful contractions of the whole facial musculature. So although not painful and not life threatening, a very disabling condition.
So just talking about investigation. The imaging studies are not very good at demonstrating the common underlying causes of the problem. And this particular scan is one where we do have evidence and I will just highlight that for you. So these are both MR studies. On the left is an MR angiogram and this is the basilar artery here coming from the junction of the two vertebral arteries. And this is the common artery that affects the trigeminal nerve. This is the superior cerebellar artery and on the patients left hand side, you will appreciate that it loops down here rather than on the other side going straight across. And what the axial MR demonstrates is that on the patient’s left-hand side, that is the trigeminal nerve, and I will just erase that so you can see that. So on the patient’s right-hand side, that is the trigeminal nerve. Trigeminal nerve on the left-hand side. That is an artery on the patient’s right and here there is an artery wedged in between the pons and the trigeminal nerve, and this is the typical finding in trigeminal neuralgia. The problem though is that often the MRI is not sensitive enough to be able to reveal these abnormalities and so an MRI that looks normal may actually be a false negative.
This is just an example demonstrating an artery compressing the facial nerve. So it is similar pathology. And these are other types of pathology. So here is a small meningioma on the left with a T2 MRI contrast enhancement in the right panel. I think in the patient because it is compressing the trigeminal nerve it is causing trigeminal neuralgia. In patients with multiple sclerosis, it is possible to sometimes see demyelination just in the pons at the entry of the trigeminal nerve, but if there is demyelination in the nerve itself that is generally not very easily seen.
So for patients who present with the pain manifestations of cranial nerve hyperfunctions, so that is trigeminal neuralgia and glossopharyngeal neuralgia, the first line of treatment is absolutely medical. And Tegretol really is the first line of treatment. And these are all anticonvulsant medications and it makes sense, because we are trying to prevent the short circuiting between the nerve fibres in these nerves. So, we would always start patients on Tegretol. For patients who cannot tolerate Tegretol we can try Dilantin, but that has probably been superseded by gabapentin these days. So we try Tegretol first, gabapentin second. Maybe try Dilantin but if they are not responding well to the other medications then they are not likely to respond to Dilantin. But it is absolutely the first line of treatment for pain syndromes.
And the second line of treatment for the pain from trigeminal neuralgia is an ablative procedure. Now what is meant by that is that we try to damage, purposefully damage, part of the trigeminal nerve so that we reduce the amount of sensory input coming through the nerve and so we reduce the amount of short circuiting that occurs. And there are quite a few different ways of achieving that type of damage. So it can be with radiofrequency. These are all done with a needle passed through the face and coming up into the Gasserian ganglion at the base of the skull, and then damaging the ganglion either with radiofrequency lesion or by having a balloon at the end of the needle that we blow up and compress the nerve with, or by injecting glycerol. Or we can use radiosurgery such as the gamma knife to damage the nerve. Now these are generally effective in the short term, but what this graph demonstrates is that there is almost certain recurrence of the pain over time. So if we look over about a five or ten year period the pain recurs in the vast majority of patients. And so, whilst these treatments are reasonable to try in the short term and so probably useful for elderly patients and those who are unfit for more direct surgery, they are not really effective in the long term. There is not a similar type of treatment for glossopharyngeal neuralgia except for radiosurgery because the glossopharyngeal nerve is not accessible with a needle through the face.
Radiosurgery is where there is a single dose of radiation, so this is really just a schematic diagram showing that we can deliver a radiation beam from multiple different angles so that where the beams intersect there is a very high dose. And on the right panel is a treatment plan showing that this part of the nerve gets a very high dose of radiation and there is almost no radiation to the surrounding structures and particularly CSF which obviously does not matter. And that is an effective treatment but is an ablative procedure that damages part of the nerve.
Obviously hemifacial spasm is different and so the medical or the non-surgical treatment is Botox. And so, Botox can be delivered to the facial nerve in the face with just the right dose and this is very effective and I would be reluctant to consider surgery for patients with hemifacial spasm unless they have at least tried Botox. The downside of Botox is that again it is only short-lived and after multiple administrations patients tend to develop a degree of permanent facial weakness. And so whilst Botox is useful to try, I think there is a limit and certainly patients should be considering other forms of treatment if they start to develop any permanent weakness in the facial muscles.
So that then brings us to the direct surgery and here we are talking about the vascular compression. Obviously if there is meningioma or an AVM then those get treated. But here we are talking about vascular compression and I will just show, this is that same image that I showed before where the artery is compressing the nerve and the surgical treatment aims to relieve that compression on the nerve and here in this artistic illustration by separating the artery from the nerve with some sort of padding, in this case it will be a Teflon pledget and I will show you an example of that in a minute.
So I am showing a video here and I understand that that does not come through as a constant video. I will just go back. So what we are seeing here is the trigeminal nerve and that is an artery. And what I am doing here is dissecting out the artery and what we found was a little branch of the artery was wedged in that angle between the trigeminal nerve and the pons which you can push that there, and we have managed in this case to bring that little loop of artery out onto the other side of the trigeminal nerve. So the original problem was that this really beautiful little loop of artery was on the other side of this nerve, just constantly pulsing away and causing compression of the nerve in that acute angle between the nerve and the pons. And this is a fantastic surgical outcome which is to move the artery completely away from that location and it is no longer compressing the nerve.
This is another case where it is a hemifacial spasm case. I am showing you here the approach over the cerebellum. So we opened the dura. This is the dura over the petrous bone. And as we zoom in you will see the facial nerve coming into view. So this is the facial nerve here. The videos will be able to play on the recorded recording of this webinar. I know they are not coming across smoothly now but they will be available on the recorded version. And what we are doing here is just dividing the arachnoid that is around the facial nerve and what is coming into view here is a look at what is probably the AICA coming up and you will appreciate shortly, it is compressing the facial nerve. This is actually the eighth nerve and the facial nerve is just on the other side of that seventh and eighth complex. So here the artery is coming up. Just dividing the arachnoid here over the lower cranial nerves. This is nine, ten and 11 cranial nerves just here so we can see those. As the video plays I will just move it forward for you so we can bring it in. So here, this artery is too big to pull away from the nerve. If I did that I would risk pulling the perforating branches off it and causing a brain stem stroke. So here I have got just a little bit of Teflon felt that we have carefully shaped in such a way that I can put it between the nerve and the artery. So that will just keep them separated, and as the artery pulsates, that pulsation is dissipated by that Teflon padding between the artery and the nerve and the nerve will no longer get that short circuiting from the compression and the demyelination.
And just to compare this to the outcomes from the ablative procedures. So here on the right side, and I just want to draw your attention to the Y axis which is on the right side these are those ablative procedures that almost always recur over a five to ten year period. This is on the left, the results of surgical decompression. But here the Y axis only goes to 70%, so although there is a degree of recurrence over time, this is over 10 years. Over 10 years there is only a 30% recurrence. And even with the ones that recur, they are much more easily managed medically. So, the message here really is that surgical decompression although it might be considered to be a more invasive procedure and more for patients to go through, has clear advantages in the efficacy particularly over the longer term.
So just a summary of that is that medical treatment is absolutely the first line and should always be tried before going to surgery, but if medical therapy is not sufficient, and often of course this is elderly patients who develop unsteadiness because of high doses of Tegretol. But even in elderly patients it is quite reasonable to consider the type of surgery, unless they are very frail or if there are other risks with surgery. So that is the end of the presentation and I am very happy to take some questions.
Sammi: Fantastic. Are there any questions that have come through at this stage, Tim?
Tim: So the one which I think you covered, came in early and I think you have covered the majority of this. When are local injectable therapies for trigeminal neuralgia used, and how effective are they? I think you have covered that quite significantly but there are other injectable therapies like the specific use of Botox, and I imagine steroid is not very useful given that pathology of the direct pressure.
Marcus: Yes, not for trigeminal neuralgia. So it is only the anticonvulsant type medications that have any efficacy. I mean obviously when a patient comes in in extreme severe pain, we will use narcotics, but that would only be as a temporising measure before going on to other treatments.
Tim: Yes, and they are often not that helpful for neuropathic pain. Someone else asking, should we order MRI for all cases baseline?
Marcus: And the answer to that is absolutely yes because, not because we are trying to see the vessel which is the most common cause, it is really just to make sure there is not a meningioma or some other lesion that is causing the trigeminal neuralgia. So the answer is absolutely yes. But it is for that reason, not to try and look for the blood vessel.
Tim: Yes. I suspect that means we are referring to you many of our patients, I do not know that it would be on Medicare if we were directly requesting the MRI.
Marcus: I think so. GP requested MRI head, I mean I guess you can call it headache because it is in the head, would probably qualify. I was going to mention that, I mean I know you are all very adept, and I am probably teaching you to suck eggs a bit in a sense, but you are very adept at treating patients, but I do generally like to have a neurologist involved if we are ever considering surgery. I just would always want them to have seen a neurologist and making sure that we have exhausted all medical therapy before we go onto surgery. You know particularly when it comes to you know, have the right dose of gabapentin and so on. Just to sort of dot the I’s and cross the T’s before going to surgery.
Tim: We have got someone just asking, they often use pregabalin, Lyrica. Is that as efficacious as gabapentin?
Marcus: Ah, yes I think so. None of them are as good as Tegretol to be honest. I think Tegretol really should be the first line.
Marcus: They are certainly worth trying. I mean, as I say it is worth trying all those things before going to surgery, but my experience is that if a patient is not doing well with Tegretol, they do not, it is not common that they would be more efficaciously managed with others. It is only if they have got an allergy to Tegretol that the others really come into play.
Tim: Someone is asking if medicinal cannabinoids are at all useful for trigeminal neuralgia?
Marcus: I have not tried that. I mean probably. But I would probably put that in the basket with narcotic really, where it is not really going to be addressing the underlying mechanism and you know, it is not a life threatening condition. It is not a terminal condition. But, you know, I suppose we would be waiting for some sort of clinical trial. I will not be sending my patients for that, but would not object to it if they wanted to try it.
Tim: Someone else is asking about the role of acupuncture.
Marcus: Again, I think you know like a lot of pain syndromes, acupuncture is helpful in the short term. I have not seen it be effective beyond that for trigeminal neuralgia pain patients. It’s worth trying, it is not causing any harm.
Tim: We have had a few people asking about amitriptyline, whether that is useful?
Marcus: I have not seen that be useful, no.
Tim: And if medication is helpful, can that be carried on until it is not helpful? I mean I think we are learning that it tends not to be effective in the long term.
Marcus: Yes. I mean the best outcome is if the patient becomes well managed with Tegretol and they just stay on that for the rest of their life. I mean, they will often go through periods of remission of course. When a patient first presents it is may not be as severe and once on Tegretol the pain goes away. You take them off and they are okay for a couple of years. And then you put them back on again. And of course I obviously have a slightly biased perspective as I am seeing the patients where they exhaust that. But absolutely worth trying. I think it is better for a patient to have long term Tegretol than to have an invasive procedure. So it is only if they exhaust that.
Tim: Absolutely. There are a few other questions, but I note we have ticked over into eight thirty, so we may take those questions and answer them, but I do not think there is anything particularly major and you have covered an awful lot of ground there. So thank you very much.
These are the learning outcomes that we set ourselves at the beginning and I think we have covered these with some room to spare. We have identified the clinical features of trigeminal neuralgia, hemifacial spasm and glossopharyngeal neuralgia. We have recognised the cause of trigeminal neuralgia and other cranial nerve hyperfunctions. We have looked at the treatment options for cranial nerve hyperfunction. We have identified the pathophysiology of sinus disease and we now know the optimal management and rationale for chronic rhinosinusitis.
So thank you very much. We have gone through an awful lot tonight and I think it has been very useful. And thank you Sammi for operating all the IT system and guiding us all through this very well. Thank you very much and thank you every one for joining us this evening.
Sammi: Great. Thanks Tim and also again thank you to Marcus and Ray for presenting tonight and everybody online, we really hope you enjoyed the session and enjoy the rest of your evening.