Hello, everyone. Today I'm going to be presenting about the equine neurological examination. But particularly this time I'm gonna be focusing on neck pathology and what that might look like and what we can do about it, in with our patients.
Mhm. Through this book, we're gonna have a look at theological examination. Both a static and a dynamic form.
What further diagnostics we can be using, both imaging, and various other forms. Then we're gonna look at neck pathology that we might be coming across, and then look at particularly surgical and non surgical interventions. And a big thank you to Rachel Tucker, who's one of the surgeons here, who has provided some of the images and some of the slides and also for promoting this side of the business.
And, some really new surgeries, which I I'll go through shortly when we think about neurologic disease, that it moment, zeitgeist is very much the neck. And that's the bit that everyone's interested in. But also we can't forget the ongoing sort of medical reasons that leading to neurologic true neurologic disease.
When we look at our our medical face. Brex is often AAA common one that these horses are going to be presenting with mild neurologic deficits. Trauma.
And then we start to look at the cervical, cervical diseases, osteoarthritis, CBM, and things like that. Also, EHV one is always one that we should be considering. If there are any concerns about pyrexia, then we should be testing for EHV one in each and every one of those cases, especially before referring.
And if you are thinking about referring neurologic cases that are acute, always take talk to your referral clinic before they come in. Just in case they are worried about EHV a whole bunch of others that we start to get into the more and more infrequent. So, Halili, which is the, the the worm, the parasite that can get into the brain meningitis, neoplasia, THO.
These are all things that we see and come across and are on our differential list. But ones we're not really gonna talk about we stepped into the ones that are at our door most of the time. The Borno virus is one that we eat very occasionally in the UK causing viral encephalitis.
And then if your horse has been over in Argentina, or America you might be talking about E PM. But it would have to have been transported, from those countries and West Nile virus. You know, we're we're seeing blue tongue, definitely making a big old impact at the moment in, the farm world.
And so you can imagine West Nile virus, can't be too far behind, especially with, changes in in global temperatures. At the moment. You think about FS as a separate group, that's all we sent.
We're definitely not talking about that today. But it's a whole another set of neurologic diseases and processes that might, go on. And then I'm gonna connect.
You have Medicare and the other programme, at at the separate degree. When we think about a neurological examination, it's essential that we do a static neurological examination in this because it's very easy to go straight to the diagnosis of the neck pathology, even though actually there could be a central lesion that could be causing very similar symptoms. So always do this as pass the neurological examination to start with and then move on to the dynamic part later on.
I used to link all of these in as 1 to 1 to 12. But more recently, I now sort of group them in groups. Because it makes the examination so much easier if we look at the ocular examination, we talk about the the ocular motor, the trochlear and abducent.
And I'm gonna go through each of these in turn, in the next couple of slides. We then look at our facial examination, and we're looking at the trigeminal and the facial. And then finally, we're left with swallowing.
And it leaves a few outliers. I in that group so we can talk about those individually. If we group them like that, then you always get those, well covered in your examination.
We're talking about our, beginning of our cranial nerves. If we think about, olfactory often I just hold a little bit of food in one hand and see if they can sniff it. Very crude.
But it's the only way that we have that we can do it. We then think about, the eye examination. We're doing an optic.
We're doing a minute examination. And this is looking at cranial nerve, two going in and then cranial nerve seven coming out to lead to the blink reflex. It's essential that you don't touch the, the eyelashes or cause enough air movement that you might be causing a sensation on the cornea.
Because that will obviously change which nerve we are involving in the cranial nerve examination. If we then look at a, PLR so pupillary light reflex. We're also looking both at the constriction of the pupil, but also the dazzle reflex.
So we're talking about, optic nerve going in and oculomotor coming out to cause the constriction of the pupil. But also, we should be seeing the facial nerve reflex of the, eyelids closing. And it's important to note that we can have the PLR without a visual ability in the horse, because it could be short circling and missing the visual and, centre of the brain and leading to just the PLR.
You should also be assessing the consensual re reflex. So when you shine in the left eye, you should be getting some degree of, constriction of the pupil in the right eye as well, and vice versa. And we should always be assessing those when we consider trochlear.
We're looking at the movement of the eye and the same as with the abducent. So we should be seeing, trism with it. So when you lift the head up, you could see that a reflect down and keep horizontal.
And we should also be doing, nystagmus, which should be normal when you move to the left. You should see the fast face to the left and then the slow face to the right and vice versa. So you move to the right, you get the fast face to the right and the slow face to the left.
And that is a physiological nystagmus that we all have when we turn our heads. And Abu is going to do your as well as some of the eye movement is also going to be doing the retract of bulby. So when you put the gentle pressure on the eye, you should feel that eye retract into the back of the globe.
When we do any of the sensation ones, it's really important that the same person does it each time. Because everyone's touch is a little bit different. So it's really important that, you you do both eyes at the same time and then trigeminal at the same time with yourself.
These are some images that, I borrowed from, University of Georgia. And they just sort of show that the important optic, cranial nerve arc, that's that I've just talking about a moment ago. So with the PLR, we're looking at a a cranial nerve, Two optic, and then coming out as a cranial nerve three with the ocular motor dazzle is a two and a seven.
So cranial node two in set and, facial out. And then when we look at a menace, we see a cranial node two in and seven out. This is where we have to make sure that we don't involve the palpebra reflex when we're doing the menace.
Because if we do, we start to involve cranial nerve number five, trigeminal with seven out, which can definitely alter the interpretation of a cranial nerve examination. If you have a positive set of five, but a negative two following is a whole group of of nerves your glyco anal, your hypoglossal and your vagus. Some of them we can test relatively individually.
Others We sort of lump together until we have a a significant problem. So Glossop anal, is gonna be doing a lot more of the tongue so you can move that tongue to the left and the right, See if the tongue tone is equal on both sides. Hypoglossal and gloss angle I normally test with just food is the truth of it.
Unless I have significant concern, then I'm gonna start looking in there and and being a little bit more critical, but just allowing them to eat, do they swallow? Do they quit and have no dental disease? When we look at the vagus again, it's all part and parcel of swallowing.
But we can be a little bit more specific. We do two things. One is the slap test.
So you hold around the base of the larynx and then you hit over the withers area and you should feel the contralateral aino, flutter under your fingers at at the larynx and then you swap to the other side and do the same thing. Easy in a thoroughbred with a nice thin neck, much harder in a cob with a big, thick neck. So you can then obviously scope and have a look down there and see if you've actually got any abnormalities and any movement issues going on there that might might be involved, obviously of note is that you can have recurrent angio paralysis, which is not a central lesion that is a peripheral lesion and something completely different to what we're talking about.
If you think about the facial examination in itself, this is sort of diving into, cranial nose five and seven. So five is our trigeminal, and this is sensation mostly to the face. There are three branches your maxillary, your mandibular and ophthalmic, and it's important to test each one of those individually.
Remember, though, that your mandibular is often pretty attenuated the response. And so, poking down on that lower jaw is I. I don't even in the video you can You can blink over the ham and over the, man maxillary.
And then you sort of go down into the mandibular and you're getting very little response. If you're genuinely worried about a mandibular branch disease process, then you can always use a needle or something like that, which they will respond to, obviously being very careful. The other thing that it does is that it does the motors motor to muscles of mastication.
And so it's important to assess each of those muscles in turn. So the mass is on either side. I normally look and then feel in comparison to your temporal, temporomandibular joint.
You've got your, temporalis up underneath the forelock. So move that forelock out the way and then also your terabits, which are behind the, eye and so you can get syncing. There are others, but they're the ones that we can generally assess from the outside of the horse when we look at the facial nerve itself.
This is motor to the muscles of expression. So we can see this in this picture. On the right hand side, we've lost, the facial nerve on the left hand side of that horse.
So we've got an ear droop. We've got some Tosis, and we've also got muscle deviation to the right because of the in inherent tone of the muscles on the right hand side. Seven, though, is also important in a couple of other things.
So it's involved in salivation. It's involved in LA cremation and also taste to the proximal third of the tongue. I don't think I've ever managed to diagnose the last one.
But theoretically, they they would lose taste and sensation there. Salivation, Lac Cremation particularly, can be important because not only are you going to be have is the horse going to be unable to blink, but also so you're gonna get a linear ulcer because of that. And it's also gonna have much less lack formation.
Which is going to mean that this horse is far more prone to ulceration and might need a tar or ify to keep that in place. I mentioned olfactory already. It test, very crude, but it's it's one that we try.
Vestibular. Cochlear is one that is involved in temporo hyoid ostro temporo hio osteoarthropathy. So we see it, semi commonly with our older horses.
And there are two parts to this. So the cochlear is you're hearing you can do clapping and things like that to try and test it. Very crude again.
Or if you're lucky enough to have excuse me, that that Excuse me. If you're lucky enough to have somewhere with, brainstem auditory evoked response, test a bear test, then you can actually assess whether or not there is hearing in either of the years. Very few places have that available in the UK.
And there are more places in the US do have it. The vestibular side of it, though, is the one that we're often more in interested in. So you're gonna get vestibular signs.
And in most horses, we're talking about a peripheral disease rather than a central disease. So once that nerve is exiting the skull, that's where we sort of start to to worry. In most cases, we do see central vestibular disease occasionally.
But not very often. What you're going to be assessing for is is there any sagus? It should be physiological and stags, as I mentioned earlier.
Whereas, you know, this has, abnormal nagma. And you can see that blink often seems to go with it. When we talk about a peripheral lesion, the, the nystagmus the fast phase will be away from the lesion.
So if the temporal hy osteoarthropathy is on the right hand side, that fast phase will be to the left. If we then have a central vestibular disease, that nystagmus can go either way horizontally, it can go vertically, and it can go rotatory. So if you start to see a vertical or rotatory, you know you're into a central lesion rather than a peripheral lesion.
The horizontal, though, is much harder, and you have to work that one out. Through further imaging and things like that, these horses will also circle because you've lost the vestibular disease. Sorry.
Vestibular response on that side and a head tilt. So their their body is saying if the if the vestibular side is knocked out on the right, that we're pushing up with the left hand side, keeping it nice and straight and upright against gravity. The right won't be responding appropriately, So you're sinking into that side circling and the head tilt towards it.
The final one is your accessory. Which does, some of the muscles of the shoulder and neck. So again, when they're standing nice and square, you assess down the neck, and into the chest.
Assuming that's all looking pretty if we go to our dynamic examination, and it's really important that we consider the concept that sometimes neurologic disease can look like, sorry. Lameness can look like neurologic disease. So the first question I always ask in these cases is Is this horse actually lame?
And if the answer is no, then we carry on great line, walk and crop. Part and parcel of that is, is the lame man, but also, you know, starting to get that feel for this horse, of what it might do. And this is a lovely video where you can see the way you can see that tail swinging a lot.
That nor slightly abnormal pelvic movement, would say that this horse isn't quite normal in its preception and and and its movement. It's just giving you that little time to start to have a look. Always do a head up straight line, walk a different horse.
And what you're looking for here is to try and take away the the visual acuity. And therefore, if there is any vestibular disease, you're going to make it much worse because horses are far better at looking where their feet are going and you stop that. And then the clinical signs get much worse.
So it's just gonna exacerbate these mild neurologic diseases. A little bit step and pine is, a useful tool. And we can sort of highlight it a little bit more when we get into the tight turns.
And what you should be trying to do is a quick, sharp turn left and right as as you go along, we often do it on and off surfaces just to try and trick the horse into making a mistake a little bit just to try and exacerbate any neurologic diseases. We're looking for circumduction in the hind limbs. Stumbling, incorrect placement, particularly when you're stepping over the curb that we can see in there pose the fines can be very difficult.
So more and more now I place the poles in a very random distance between each of them and I get the horses to turn in and out of them. Often. I make a sort of a bit of a square or a CR and make them walk in and out round and round to get the the handler to move them in very random directions.
Often, horses who are quite lazy will be quite happy to hit these poles with their back legs and sometimes with their front legs, and that that is a symptom, that I. I don't really pay attention to much as long as it's not severe. It's more if they start to step onto the pole and slip and roll that pole, that it becomes more interesting.
The tool is one that very easy to over fabric. I think you have to do it with care, and what we're looking for is we're trying to decide. Is this horse normal?
Is it a toxic or is it weak? If we think about a taxi as you do that tail pool, the footfall should start to become abnormal. So instead of being a nice, gentle rhythm, it's gonna stumble and trip, and it's gonna that foot rhythm is gonna change.
Weakness is going to be that they're willing to come with you, but their footfall stays regular one thing with some of these horses. They're very compliant. So care with the weakness side of things to say, Is this really a low motor neurone disease?
Or actually, is it just that the horse is compliant? And a lot of what I would deem would be relatively normal. Horses have a relatively weak tail, so if we have one abnormality, don't take too much notice of it within reason.
Hills are really useful because they exacerbate symptoms. And as we go up the hill, we'll often see the fore limbs and or both, but particularly for limbs. Sorry Abbing into the ground.
And then as we go down, you'll see that sort of slightly floaty hypometric gate in the fore limbs as you go down. One thing if there is pain in the hind limbs, particularly if there's any orthopaedic pain, they'll often sink as they walk down a little bit. And that's not a neurologic disease that is just discomfort in them trying to deal with the slope.
So that's why we need to know if these horses are lame before we start. The soles are the best ones for giving you a lot of information, ensuring that the horse is always walking forwards as you move as you're spinning them. You're gonna be looking particularly at those hind limbs.
Are they C conducting? Are they crossing over? Are they stumbling, swaying in the fore Limbs?
Are they crossing over willingly? And also are they interfering at all? And then you do it both ways, obviously, and it's quite good to do a slow and a fast phase of that turning because you're gonna show different things.
I'm not a big believer in hopping because A If it's found in neurological, you're putting yourself and the horse at significant risk. And also it's something that horses aren't used to doing. So they often act very weirdly and secondly, with placement of feet on top of feet.
Great. If they're profoundly neurologic, you'll get the answer you want. But probably by then you already know the horse is, clinically abnormal.
But also, we see you know, a lot of the Polo pony a lot of the dressage horses that they are willing to do whatever they're told. And so sometimes we'll stand there because the human has told them to do so. Whereas I find this is something Monica Aleman put me over in America.
My residency is if we pan and stop and we do that repeatedly and give them a chance to correct, they should correct into a fairly natural position. I'm not saying these horses should have all 4 ft in exactly the right place, but they should be at a point where they're able to run away. And if they're facing left right there's one miles behind.
Then we know there's something wrong and we should be looking at that if you're talking specifically about neck. But this is also just part of the whole, examination. We could be doing neck sections, which is a very good horse, is willing to quit.
But if needed, you should put them against the wall so that they can't swing their butt away from you. And we should be seeing that head come round in a vertical plane without any twist. If they start to twist, you know that they're starting to cheat, then also a neck down examination.
And if you can do a neck up, then then do that as well. I also palpate the neck at this stage, knowing that what we're trying to find is any random discrepancies in the size of, say, the, a PJS the, the joints within the vertebrae, Or is there any asymmetry? Is there atrophy?
Is there hypertrophy? Is there increased tone? Is there increased sensation pain all along the neck?
It's important to note that you you can't feel many of the A PJS throughout the neck in a nicely muscled horse. It's only as they get thinner and it becomes more obvious. And also it's really good to feel around each joint and really palpate to see if there's any deep pain.
Finally, some of the other bits are curbs. This is obviously a profoundly neurological board, and the The Curb is a really useful way to support them into making mistakes. So this one obviously becomes hyper metric behind.
It actually clips its feet as it goes over the curb. But not not everywhere has it. It's a nice little extra, and this is just an example of bad pen I.
I got the nurse to do it on purpose. You can see we're not walking forwards with those front legs aren't moving forward. And actually, the horse starts to look neurological.
This is a normal horse. Who I just was forcing it to do it wrong. So if that's happening, correct them because you cannot interpret any turning when it's done like that.
And finally, the blindfold, is a great addition for vestibular disease. Should all be wearing hats nowadays. So I apologise for the for the video on that front.
Normally, I do it with something like a coat where we can whip it off nice and quickly, or a towel. And then we just try and walk them in a normal horse. They will move in the end, although they'll be reluctant and there won't be any problems.
You know this one? Although it's not moving forward, it moves well backwards. It does not have a vestibular disease.
It is now exacerbated by the blindfold. If you genuinely are worried about a vestibular disease, then be very careful when you do this cos they will collapse onto the floor. The whole point of this examination up now is trying to decide the neural localization so that we can start to investigate further with dynamic imaging or whatever it might be.
And so the understanding of where these things are is critical. First question I always ask the interns is Is the horse mentation normal? Yes or no?
And if the answer is yes, then we can move on from the cerebrum. The central part of it Are all cranial nerves normal? Yes.
No. Yes, OK, The brain stem is normal so we can kind of rule out the head. The next question I ask is What are the differences in each leg?
Is it unilateral? Is it bilateral? Is it front?
Is it hind? Because then we can start to say which part of the vertebrae it might be. And also we asked the question.
Is it upper motor neuron or lower motor neuron? So is it truly ataxic? Or is it a weak pais sort of thing?
Because that's again going to really narrow that that localization down. And when we think about most horses we talk, most lesions are gonna be within the neck, within the cervical vertebrae C seven C one to C seven. They might go into the first thoracic vertebrae and so we can have an effect on both the four and the Hinds.
If we start to just have high NS. Theoretically, it could be the neck. Or it could be further back, again, still with the common sense and most of the time, it's just the neck.
Kidding is essential, and it's really important to remember that grade Everyone can have a one difference grade that's been shown in, in a good study. So if you're saying one and somebody's saying two, it's absolutely fine. As long as we're not saying one and five, we're all good.
This is the modified Mayhew scale for a taxi, so it's a really good, simple way to look at it and and from my perspective, I. I simplified even more for when I'm talking to owners, so five is lying down. Four, as you can make them fall over three is it's really obvious, in walk and in all phases of the the examination.
Two is that you have to do tests, but it's consistent and it's fairly obvious. One is you have to do tests and it's, often inconsistent and or very difficult to see and obviously zero is normal when we think about where it might be in the sort of the upper motor neuron versus lower motor neuron. So C one to C six we've got and C seven You're gonna have upper motor neuron disease.
So elongated Stride Neu Neurology Circumduction pivoting all those sorts of things. Whereas if we start to involve the one P two, you might get some lower motor neurone disease in the fall. And so, profound weakness, Short, choppy stride those sorts of things.
So if you're seeing a truly at toxic hind limb disease but a low motor neurone disease in the four limbs, you might be saying, OK, are we falling into that little window of C six T two? And obviously all the rest are are here just for information. What do we do then?
We decided that, OK, we we we're at a certain location and we're going to examine it further. What further diagnostic should we be doing? If you're worried about a cranial nerve deficit, do an ophthalmological examination.
Make sure there isn't a a globe disease that might be leading to blindness, et cetera. If you think you might have something like temporo hyd, osteoarth osteoarthropathy or a swallowing de deficit endoscopy of the guttural pouches of the pharynx. Even, an overground endoscopy To watch the horse swallow, might be helpful.
Blood work is useful to make sure we don't have liver disease. If we're talking about the central disease, A and so always worthwhile considering in these cases. Otherwise, we start to get into our imaging modalities of CT MRI and radiography Go to each of those individually CS F sampling.
If we're doing AAA CT and then if you in a sort of slightly weird and wonderful Sometimes you end up being muscle cases, you know, these some of the the BS SM type two, and things like that. So muscle biopsies might be warranted, but probably doing muscle enzymes during the examination. Post exercise, et cetera to to prove that point, you can do EMGEEG all those sorts of things if people have the ability again.
Really not very easy in the UK. So not something that we'll talk about, but specifically Now we're gonna talk about neck and and their pathology. We're gonna talk about Firstly, how do they present?
What are we gonna be sent by the owner or by the referring vet? Sometimes they have overt neuro neurologic disease. So that's an easy starting point.
You know, the the vets decided that this horse is is stumbling, tripping, and we know what we're doing. So we investigate further. Maybe there's neck pain.
You know that on flexion, et cetera, the horses is painful, But remember that neck pain doesn't mean an orthopaedic dis disease. Sorry. A skeletal disease could be muscular or tenderness, so it's always worth looking at new ligaments.
Bursas et cetera. That falls into the sports medicine world, far from where I feel comfortable. But that would be something that I would involve another person in.
Quite often, though, these are now the poor performance cases, the ones that just aren't quite doing what they're doing. They might be stumbling just occasionally or tripping occasionally catching that front foot or they're just not willing to get into the outline and jumping as they should be doing. Overt neck pain obviously can be a thick, low carriage.
Difficulty eating cos they're not willing to bring that head down or reduced range of motion. But overt neck pain is relatively uncommon, I would say, whereas subtle, other times we're talking about performance are willing to work in a bit. Maybe these gate deficits are mentioned.
Changes in behaviour, and often a very nonspecifi signs of pain and discomfort. And the horse just isn't quite right. Imaging.
Once we've decided the neck is the problem, imaging is the next stage. Radiography is very good as a starting point. In these cases, lateral radiographs are a great point, and it's starting.
It is important that these are truly lateral. Otherwise, interpretation is pointless because you will get abnormalities when these are not lateral. If you've got the facilities the, powerful generator, et cetera, then obliques can add a lot into your investigation of the joints.
The A PJS DVS are a wonderful thing, but are very difficult. Unless you have a quite a small horse, you then can add synth grey, ultrasound, CT and myelogram. But if we look at radiography, what we're sort of looking at, This is what I'm talking about.
This this one is not very lateral in this image right in the centre. So, you have to be careful about interpreting the, a P eight and also the size of the vertebrae and the size of the vertebral canal. What's also important to note is that as you sort of go out to the outside of the, the image on the right hand side, you start to see what looks like a small for Raymon.
and that is only because you've got diversion, distraction of the image right on the edge. And so you're definitely not getting a nice lateral Pointer, point at that point. So just down here is where we're sort of worried about, these ones are again looking at your foramen and you'd say, OK, a relatively normal one.
And this is at our edge where we could that is that clearly abnormal or not? Because you say OK, it's probably not completely lap at that point, so looks like an abnormal and large a BJ. We'd want to repeat the X ray and you know, we we can that on the right hand side, where we're now far more lap over that But you can see that joint is enlarged and sort of, shrinking the foramen.
That's for coming out so important to make sure that we get the the area of interest within the centre of the image. Otherwise, you can't interpret it appropriately. Leaks are a very useful thing.
It's difficult to interpret, especially when they're not done. Quite right. But these are ones where you're going to be having the the nice, obvious joint sitting out, away from the spinal column.
It's just giving you a little bit more information so that you can give it a better view without AC T we can grade changes. In the particular process joins a PJS And so it's a useful thing for if you are referring, but often we do say that they're just enlarged rather than giving a grade. And this is a a lovely paper.
That just gives you from 2009 that gives you those values, gives you some images and how to work through it. So if you're looking to do that and send stuff in, then just pull that paper up and, and use it as a guide. What's important to note, though, is that there is can be normal variations in the shape and the size of these vertebrae.
So cervical thoracic junction anatomical variation is something that we see. And it's important to note that this is not the myelopathy. This is not CBM.
This is not that we're saying, OK, there is a true stenosis or a, an increased movement between the joints. It is that the vertebra vertebrae are not normal. So B six can have un or bilateral dysplasia in the cad vertebrae laminate and that can be graded.
E Seven can have very similar and it can be moving from C six and then 71. You can have very a in the cap of the P, and even have dysplastic ribs. If you start to see any of these sort of slight, weird changes in the vertebrae, it's important to have a look back at these papers and say, OK, are they normal, or are are they abnormal?
And in one study, they found that 11 to 39% of C, of horses multiple breeds, particularly all bloods and thoroughbreds had these abnormalities and 50% of the variations had no clinical science. And there was no objective evidence in any of those studies that the anatomical variations were causing any of the symptoms or the TJ D. So, you know, the these slight variations are probably just normal, and not something that we should worry about.
Although we are constantly learning when we talk about the these sort of disease processes in tgray is obviously a very useful tool. Useful modality. It's gonna highlight where there is increased turnover, of bone.
And so it's a really good general investigation for poor performance and pain. It doesn't always highlight pain, but it it highlights an area of increased tenor which often is associated with pain. It's relatively insensitive, along the cervical spine.
But it can give us a hint. So, you know, in that bottom middle pitch, you're starting to see one joint that is looking particularly hot. So you would then say, OK, let's let's work on that a little bit.
It's really important that you do both a left and a right if your if your practise is doing these, and The important thing is that it's always gonna be essential to do further diagnostics following this imaging. This is not going to give you the answer. This is going to give you OK, We are going to look at the neck rather than the other location that we might be worried about in itself.
It's not helpful with giving you a diagnosis. It is just guiding you. So it's an expensive tool, to point us in the right direction.
And we often get to that point of just trying to decide. Do we go to synth Grey? Because this is quite a nebulous case, and we don't know where to to really highlight Or do we go down the CT with a myelogram, and use our money wisely to get that that good imaging modality.
It's obviously very useful, both for treatment, so that we can be, medicating them. Can look at the new ligament and bursa. As I said that that is definitely a Rachel comment.
Not a not a me comment, because I, I wouldn't know what I was looking at. In reality, when you're looking at these joints, you're looking at the the the joint margins are Are there osteophytes or anything along those lines is the synovitis is there thickened joint capsule? And we can get samples obviously from those joints to see if they are inflamed.
So it's a useful addition. Often, we already know which joints are abnormal from CT or X. Ray.
So often we're just assessing it as part of the treatment. No doubt. CS F.
I've mentioned it is a separate slide, just in case we're talking about a more central disease. Three locations. Now that we can take it from your Atlantic occipital.
Probably the easiest because you've got a horse under general anaesthesia. It's a nice big hole. We do it for myelograms.
We're very used to it, and it's and it's quick. Once horse is down, the problem is, obviously you need the horse recumbent. The LS lumbosacral is what we've been doing for a very long time.
You need to have good sedation. I generally have a a nose twitch on them in stocks because they often will kick rear. Well, not often.
They very occasionally kick rear or launch forward as you go through the Jura. The problem is that we know that when you take samples from the LS and the A O tap, they are very different in their cell population. So if we talk about a proto cell, my, my encephalopathy, you might have a near negative result when we do an LS tap, but a clearly positive result when we're doing an a O, we've been doing a lot more C one C, two standing approach to the, the CS F and getting, CS F samples.
That way, it's actually a very easy technique. Once, that's not true. It is a very difficult technique, but it is a very, reliable technique and one that actually, I'm I feel very comfortable now doing on a regular basis.
Definitely not something to be doing in the field. It needs to be in stocks. It needs to be safely done and with somebody who is very used to it.
But it means that we can get those framing those rostral samples without having to do a general anaesthetic. PT computers. Demography has become the imaging modality of choice.
If if we're allowed to we You know, thanks to our imaging team, our surgery team and the medicine team, we We are managing to get some really amazing images now, obviously, it requires a general anaesthetic and, total intravenous, anaesthesia to maintain them. You can't. At least not with our set up.
You can't do inhalational. And the reason for that is that the the machine is moving in and out so much that you wouldn't be able to maintain the, I inhalational anaesthetics. We, we were using GGE and, ketamine and everything like that.
Now we're using a dazzle ketamine infusions, and they're working a bit fantastically. And we're very comfortable with that as a technique with the whiteboard gantry. Our 80 centimetre one and a lot of shoving and pushing, which we've mastered over time.
We are able to get pretty much the whole neck in the in most horses, and in some way you're getting down to T one, T two and sometimes even further down. If they're they're small, we can then do a 3D multi planar reconstruction, removing all the tissues to to give you, to get rid of super in position, which is giving you a nice view, especially for the surgeons. When we start talking about movement of fragments from the A PJS.
And the question often in these cases is should we just do a plain CT or should we do a myelogram? And we've come to generally the conclusion I know other practises will always do a myelogram in every single one that gets put through. But we've come to the conclusion that we should do planes when we're talking more about a painful procedure and myelograms when there is any question about neurologic disease.
And that's because myelograms don't come without risk. PT has. We've found a wide range of findings up to date, both in Bo and soft tissues.
We're unable to diagnose any, neuritis myciti, and early in, vertebral disc disease. The thing is that we're learning constantly learning in this in this area. So a lot of the stuff we're we're diagnosing is based on common sense.
And hopefully the papers are coming out more and more. Of which, you know, the the team here have published quite a few myelography is is a fantastic tool because it's going to be a if we think about a lateral radiographic one, you can only see the DI column both dorsally and vent. You cannot see any of the lateral compression.
And so the myelogram gives us that whole picture all the way around the spinal cord. The one problem with the CT is that these horses are generally in a relatively extended head position rather than a flex position. So we are always now doing AC T myelogram and then followed with neck radiographs in a flexed position to increase our sensitivity of our system.
If we look at this image and you know, if you look at it, on the left hand side we can see the DI column going in the dorsum of ventral and it looks at a quick glance pretty good. There's no areas of compression. Then we look in the right hand side one, and you can suddenly see that there is compression on the right hand side of the image from the a PJ including some of the the DI column on the right hand side.
Without myelogram CT myelogram, we wouldn't be able to diagnose that. We would say that is a completely normal drug cos there is nothing going on, in the dorsal and ventral di columns. So it's been shown to correlate well with post mortem findings.
So we are fairly confident that what we are seeing is real. It allows us to examine the sub arachnoid space looking for cord compression circumferentially rather than just dorsally. Eventually, as I've mentioned, we're getting greater and greater anatomical information, which sometimes opens more questions than answers.
But what it does is that it gives us the ability to surgically plan If, the surgery is gonna remove, a fragment or do for an anatomy. And also, if we're going to treat any of the joints, it tells us exactly which joints we should be really highlighting, but not without risk, as I mentioned, so sometimes we see worsening the pre-existing ataxia, and some of the other Sequels Celle, which will go into I said, we're not gonna get a dynamic view with CT. We're only gonna get that slightly extended view.
And we're constantly learning. What are the risks? What what are we seeing?
In one study, there was an adverse reaction rate of 95 out of 278. With some of them increasing neurologic grade afterwards, some having seizure activity and some actually having to be PTSD. Because they didn't sound or persistent seizures or or or other disease processes.
And then we shouldn't do this without lightly. And we should make specific plans for handling the cases. If there are changes subsequent to it, myelogram technique really hasn't changed over time.
You know, we we've nuanced it over how long we inject and how long we withdraw. But that's kind of it that the drugs we use are exactly the same. And so the these are two more studies that showed, a 7.2% in 100 and 80 or it's about a 36% in a smaller group in 2019, so that works out as about a 24% complication rate.
What are we seeing, though, in reality, we are seeing complications. But most of them are temporary and ones that we don't we do worry about. But we, we work with seizures is probably the most common and assumed to be because of the contrast going, with a cranial vault.
So sometimes if we see significant amount of, of, omnipaque within the brain of the on the CT, then we'll increase our midazolam doses just before recovery. And and be ready for that. Sometimes it happens for 24 hours after, so we've had to do midazolam CRIS, in some horses for 24 hours to keep them from SEIZURING.
And we're we're really aware of these really partial seizures before they become grand mal seizures. So eye twitching, muscle twitching, sort of muscle twitching, all those sorts of things. And we, the team, are very good at picking those up very early on so that we don't allow it to progress.
We've had worsening a taxi we had one in recently that was sort of grade one, a taxi and then became a grade four. A taxi afterwards and sadly, never got better. That neck was truly horrendous on CT, and interestingly, the horse compensated well up until that point.
And rarely, but we do sometimes get it as an inability to stand following the procedure. And and those ones, sadly, obviously have to be PDF. And there it it's definitely the ones that are worse before you start that we worry about that occurring.
So what are some of the pathological conditions that we're looking for? So, we could be looking for osteochondrosis. So we're looking for some Some fragments.
We could be looking for osteoarthritis with, reduction in the the frame we start to get into the slightly more weird the osteomyelitis, abscesses, subluxations things like that that are are options, but far less common. So we're gonna talk about the top few in in this presentation. Not really.
Gonna talk about CV M too much. Just, we've obviously got to highlight it. There's a There's definitely a genetic PVI.
This is two horses that I saw in America, brother and sister. Exactly the same age, through, embryo don, implantation. And you can see just quite how severe they were.
The these were PTS because, they were they were quite as severe as they are. Remembering that there are two different forms. So either compression, consistent compression.
Of the, of the spinal column or there might be increased movement. And often they will get worse between dynamic examination. Get these diagnosed.
You're talking about radiography with myelogram and IG BC T with, myelogram. Now that we are able to do that, treatment obviously has been the basket surgery historically, with the, when you've got that increased movement between the bet brain kno if there's just a S synodic bete Braine The problem with basket surgery is that you often just get a grade one improvement. So if you've got a grade four horse like those ones, at best, you're probably gonna get a grade three.
And so it's helpful to stabilise things. But it often won't give you the horse that everybody wants. Treatment.
Otherwise, it is pretty limited. And, so normally, we give a pretty guarded prognosis for return to normality. Arthritis is something that obviously is far more common.
And we see sort of spurs forming enlargement of the joints, inflammation. And often it's not actually the osteoarthritis that is compressed in the spinal cord. It is the soft tissues.
So these are ones that are responsive to treatment and should be considered for treatment. The next sort of stage up is that we can be talking about fragmentation and loose bodies. and they they can be associated with osteoarthritis.
They might be separate to osteoarthritis. And it appears that in some some cases, these seem to be clinically insignificant and are just there. In some cases, they are absolutely, clinically significant.
And so there's a hypothesis that is going on. That is, these are synovial osteochondroma Tosis. But the long and short of it is that if they are surgically accessible, they can be removed under arthroscopy.
So, Rachel Russell, and the team here have been doing that surgery. And you know, some of these horses have gone from significant neck pain, and and arthritic issues to doing much better following the surgery, and it can all be done. Arthroscopically and with good possess, this is just one sort of case that Rachel provided a five year old event horse with neck pain and and pretty low grade ataxia in the hind thems.
And when we look at the CT and looking at the C 67 facet joints. We can see that the a BJs are very enlarged and irregular. So we we've got a real curvage determinate spurs at either end.
But also that we're starting to see intra eval for Raymond that are markedly narrowed. And this is something that, you know, we're we're definitely sort of. We're starting to really fully understand that this narrowing, if you look at this one particularly is clinically significant.
And there have been some nice studies looking at Can we measure this? And can we actually work with it to know if horses are abnormal? So, this group looked at 21 bloods and they've started to measure the framing, on CT and with excellent repeatability.
And there's different sizes, in each of those joints, and that's something that we can really look at. So in intervertebral frame and narrowing in frame and narrowing, was defined as a reduction of 50% in the the frame and height when compared with the widest part of the same interval frame. And so it's important to note that in some views it may look normal.
But then if you look at these, ones down at the bottom, you can see that the front is com. The roster aspect is completely included, whereas the back isn't. Then you've got this spur.
So if you were to look across here into this view, you might see a relatively normal bit. But then you scroll forward and you start to seeing this abnormality here. And so when we compare this side to this side, we can see absolutely that this is con considerably different as long as we are, looking at it correctly.
And that's something that's very important when you review CTS. So maximum degree of narrowing was most commonly in the cranial aspect. And then the middle as, middle third, Middle Third, particularly of the of the in in Intervertebral foramen and C 67 was most commonly narrowed.
And we didn't see any at T one, T two. The problem is that we don't know what the degree of narrowing is. That is significant, but it does seem that treatment is is helping these faces.
And what about what are the symptoms of sort of compression and opathy? That we're seeing around that nerve so you might have local pain or decreased S sensitivity at that specific location. You might have neurology.
Diseases consistent with the peripheral neuropathy is affecting the brachial plexus. In other words, stumbling, tripping falling all due to four limb deficits, they might have a reduced protection of the for limb. So during all phases at war counter, trot and canter, they might not be willing to bring that for limb forward.
Often, these are you are unable to localise the lameness. They might have this idiopathic weird hopping lameness that Dyson has talked about previously might be just restricted movement. It might be that it might be more severe.
It might be un rs. It might be bucking because it's the degree of pain. The problem is that often these symptoms may be intermittent.
They may vary with head position, and also they might be subtler. And so often it becomes a a case of trying to treat and seeing If we get AAA change, does it have a radiculopathy? So that's the frame and coming out.
Number three is the the the the nerve coming out as it exits from the spinal column and if that's being squeezed, is it causing inflammation? Is it causing, a decreased ability to put that nerve to function? And Andrew here, study looking at perineural injections of the cervical spine.
So rather than trying to fix the primary problem, which is the shrinkage of the framing, can we reduce the inflammation of the nerve at that point? So he on cadaver studies looked at, whether or not the site could be injected and the answer was yes. Under ultrasound guidance.
The point is, it's only been reported in cadaver studies at the moment, but on the we have used it on a number of horses and have relatively good improvements in a lot of them. Not all of them risks are that there's some big blood vessels, where you are going to be injecting, and also you are going pretty close to the spinal cord. So you have to be careful with this injection.
This is not one to be undertaken lightly, and it's not one to do without knowing how to do it. But what are we doing now? And this is where Rachel is really sort of pushing the forefront in the UK.
There's a new technique called percutaneous full endoscopic for for a menotomy for the treatment of these cases of for a menotomy. And we are at Liber one hospital, the only practise who are offering this as a surgical technique in the UK. And Rachel is the only person who is doing it.
It's been sort of pushed by a team over in Germany and then started over in America as well. And we they are starting to do relatively high numbers of these cases. And we have Now, we've done our first one as a clinical case here, I in the last couple of weeks, and that horse is doing very well.
The goal of the surgery is to remove that bone that is compressing the spinal column there by releasing the nerve and hopefully making it much less compressed and much less painful. So these are images of of cases that have been done. So what we're trying to do is reduce this bone here, increasing the hole so that you start to get a much bigger, much happier hole that the nerve can go through.
It's a very it's a minimally invasive procedure. So what we're trying to do is we are going to be doing this. This is, it's all, via equipment.
So you're only going through one small stabbing carefully, until it's open. And so it's actually, as a system, a very minimally invasive procedure. When we look at the cases, there's been over 200 cases now, and, in in those the the team over in Germany, they were reporting an 87 partial or complete improvement, and 75 or 73% of them are returned to full use.
13% have no improvement. That's pretty significant numbers that we don't have the long term follow up on that one because this hasn't been going on on, for X number of years. Complications, obviously.
General anaesthesia. There could be excessive bleeding because obviously it is a highly vascular area which might stop the surgery being completed. And because obviously you're working very close to a large number of nerves.
There can be local nerve damage so they can theoretically be worsening of symptoms. Although it hasn't really been reported. Going forward post opera postoperatively These cases actually don't have a lot.
So, some box rest and then some hand walking and a return to, turnout and then a gradual rehabilitation exercise programme. It is possible if there are two sites to operate on a second site after two weeks, and then reassess after about 4 to 6 months, to see how they're doing. So is it possible that you can combine with injections?
If there are multiple joints that need in, treatment finally what? So sorry. Going back.
One step. Actually, this is there's a surgery that we're very excited about. And actually, I think we're seeing more and more cases that are going to be, positively affected by this as a surgical technique.
And I think without it, we are very much just sitting at steroids. That's it, which isn't curing the problem. It is only postponing the ongoing pathological changes.
So I think if you've got these cases where you are worried about neck pain, then it is always worth trying to get them into the CT if we possibly can, so that we can assess this fully and then decide if surgery might be an option, even though otherwise, if we're talking about neck pain, neck pathology, obviously oral nonsteroidals can help. The problem is, if we're talking about neuropathic pain, where there's a radiculopathy, they then they're not very good. Nonsteroidals, you need more neuropathic pain relievers such as gabapentin.
But again, that's not all that effective when you've got a squeezed nerve. You can control it for a little while, but it's always gonna get a bit worse. Systemic.
Steroids have very little effect in in experience. So local steroids in perineural or into the a BJs are very sensible. Bis phosphates might help.
So there are a couple of reports on that, but again, they're sort of slightly fallen out of favour. They have risks, with limited responses. And then obviously your a B, joint medications.
If you've got arthritis in those, the last slide is just that question with neurological disease that I think we always have to ask is should these be ridden or not ridden? The first question is, obviously what grade is it? So you know anything in 34?
No question. No, you shouldn't be writing those 12. You start to get a bit of a A question one.
I feel fairly confident that people can ride them. If you look at most dressage horse is let's be honest to you. If you were critical of them, you would say they're grade one.
Do under eighteens ride it. I would still push that back to the parents. Because of the human health risk, grade two would very much be a consenting adult only, who understands the increased risks.
Also, what's the diagnosis if this is something that is not going to get significantly worse? So you know, osteoarthritis, it's gonna sort of grumble along and you're not gonna suddenly have a horse that goes clinically, severely abnormal, whereas E PM will suddenly go abnormal. Then you can be a little bit more comfortable also, what's their intended use?
Are they a hack or are they meant to be jumping? Are they meant to be cross country? All those sorts of things.
It's always worth if possible, getting a referral for these cases so that we can get the imaging. We can get a full understanding of the disease process and often in those really low grade ones. I.
I will involve another vet within our team, one of the surgeon one medics to have another opinion as well, because I think it's always good before you write those reports to decide that. So in summary, from a net perspective, I think imaging is really progressing, and I think we need to be pushing to do more and more advanced imaging the risk of generality. The risks of TV are so small, that I think we are doing a disservice to not try and put most of these into, into the CT for further imaging.
And then we are now able to provide surgical interventions that will change the outcome rather than CT being a a reason to euthanase we we We're really now pushing for these CTS to be done so that we can treat differently. Thank you very much for listening. And obviously, if you've got questions, then please, do send them through to the team webinar vet or or through to my email, which is on the lip book website.
Thank you very much.
