Welcome to this presentation on disc disease. And what's the latest with steroids and rest? We're going to talk a bit more about other medications, but what, what the role of steroids is currently, is going to be explained, hopefully, using, a few, case analogies.
We're going to talk about really medical the. For this for this disease. When is it warranted?
How successful is it? How long should we give it before we think about surgery? And ultimately develop some criteria for surgery.
What are the cases that we should consider surgery for immediately rather than giving them a medical option? First, let's start off reviewing some disc disease facts then. So when we talk about intervertebral disc disease, we're talking about these cushions or shock absorbers that exist between the majority of the vertebra from C2 cordially all the way to the lumbar sacral space.
These shock absorbers then, are made of two major components. One, centrally, is the nucleus pulposis, and this is a highly hydrated, jelly-like structure. 80% of it is water when you're born, surrounded by annulus fibrosis, and that is collagen, which is essentially keeping the vertebrae together and keeping the nucleus porposis in place.
So you're born with this nucleus porposis, piece of jelly. Which acts as a shock absorber between the the the vertebra, and as you age, then that nucleus porpois gradually dehydrates, very slow process. Unless you are a dog that has a predisposition for that disc, dehydrating at an early age.
There's the chondro. Dystrophic dogs, such as the Daxuns, French bulldogs. And then what happens is that disc dehydrates rapidly, the the nucleus pulposis mineralizes, and so it, it has a propensity to push outside now explode outside a little bit like this, jam inside the doughnut.
And we'll come back to this analogy a bit later. So you've got the annulus fibrosis around it, and then this jelly-like structure here is pushing out, and that is gonna cause the damage to the spinal cord. So just keeping you interested with a revolving doughnut.
OK. So here is a histopath, gross pathology section of nucleus pulposis and annulus, and we can see the canal up here. We can see the nucleus pulposis here, very jelly-like, that's your shock absorber.
And then around it is your annulu fibrosis. And note a very thin rim of that dorsally, so it's not a long way for that to go until it's inside the canal. Of course, if it did go ventrally, although there's a lot more resistance to that, we probably wouldn't know much about it because there aren't obviously any neurostructures here.
And such a small amount of material going ventrally, not gonna do too much harm. But dorsally, that's where we're gonna now cause a few neurologic problems. So when we have dehydration, we have several terms that we need to just use.
Sometimes they're used interchangeably, but just to get us on the same page. We talk about disc herniation, and that just means the disc has moved out of its current place. Doesn't really imply what type of disc disease it is, but it's moved out of its correct anatomic location, usually upwards a little bit.
And that's split into two types. There's a protrusion where. The annulus pushes up into the canal by hypertrophy.
We'll talk a bit more about that. That's in our larger breed dogs, and then extrusion. That's where our mineralized material, now dehydrates nuclear material, nucleus porposis.
Explodes out like the jam in that doughnut into the spinal canal and then impacts the spinal cord and the nerve roots. So that's extrusion. So just to get us on the same page with, with that terminology.
Extrusion then most common as a component of type 1 disc disease. Now disc disease is classically split into Hanson type 1, Hansen type 2, which we'll talk about. Nuclear extrusion is type 1, where the disc, as we said, has undergone this degeneration.
Ultimately becomes more mineralized through a process of chondroid metaplasia. And then the extrusion that results hits the spinal cord with some force. And ultimately causes a spinal cord concussion and residual compression.
So we've got those two processes going on. Spinal cord gets hit, concussion, and that ultimately leads to ischemia and, and a maybe progressive dysfunction over 72 hours, which we'll talk about shortly. And then a residual compression.
Of varying amounts of nuclear material. As you said, this is primarily in chondro dystrophoid dogs. So these are gonna be our dachshunds, French bulldogs type of type of breed.
Most of the time this is going to occur acutely. With some progression over a few days, but it can be a chronic deal. And many times, what this means is that the disc did actually extrude, may have been handled medically or maybe not too much problem at the time.
. But that chronic compression has left some, ability for that disc to cause some atrophy of the spinal cord, and can get an acute on chronic presentation of intermittent pain. That's gonna be more, likely with type 2 disc disease, which we'll talk about in a second. So, as you said, chondro dystrophic breeds, and, and these are genetically predisposed to have this disc degeneration at an early age starts at about 6 months of age, and by a year of age, 75% of the discs are dehydrated, nearly all of them by 2 years.
We rarely see clinical disease by that by that time. So that's important to note, if we got a chondrodystrophic breed. That was a year of age with back pain, weakness.
Of course, we should always think about disc disease, but it's not top of the list. We'd think of other things, inflammations of, of the spinal cord and of the vertebra, trauma, obviously, maybe congenital lesions. So other things would take priority of the differential diagnosis list in a younger dog.
But after about 2 years of age, now this is when we would start to see clinical signs. We have a very complex slide here, and so don't get too bogged down by the details. This is really just to show you a couple of major things.
When the disc extrudes, we see primary. And secondary effects taking place. The primary effects is immediate concussion of the spinal cord, damages blood vessels, may lead to local haemorrhage and compression of that spinal cord, which causes what's called conduction block, meaning the spinal cord just can't get its messages down anymore.
And this is what really is a physical issue. Sometimes we can do things about that by removing the compression. But we also get then a bunch of secondary effects.
It's a multiple . Set of biochemical changes, electrolyte changes. And this has been the target for much research over several decades to try to find a drug which will improve spinal cord injury.
What we actually have is a hypoxic environment. Which gives rise to so-called cytotoxins and free radicals, and these damage the spinal cord further. It's kind of the evolution of a bruise inside your spinal cord, causing ischemia.
We have, we have increased calcium within the cells. We have potassium going outside the cells. So we've got a change now of the electrolyte environment, which means we get some abnormal.
Conduction in and around the spinal cord. So we have a hypoxic environment, we have a lot of neurotransmitters and toxins, and then we have abnormal conduction. All of these can go on progressing for 72 hours.
So take home message of this complicated slide is, we have a physical problem, and then we also have this progressive medical problem that at this stage, we're not able to do too much about, and it goes on for 72 hours. Probably all seen the dog who had back pain last night and is now paralysed this morning. And that's because in most cases that we've got this progression of of a medical change within the spinal cord.
So type 2 disc disease is usually in our larger breed dogs, the non-chondrodystrovoid dogs. This is a, this is a type of disc disease that is similar to what we would have as, as, as humans. It's a more age-related change.
So now way into maturity, when we're talking about dogs, we're talking about maybe 678 years of age. And the dehydration that takes place is across the whole structure. So we not only get a change in the nucleus, which is this time called fibroid metaplasia, just again, dehydration, so that shock absorber's not working, but we also get annulus changing, changing just with age, like the rest of the body is changing.
As we get small movements of this nucleus porposis. Because it's become mineralized, you've got a small rock or or stone in between two vertebra now. As we get those movements, then the annulu hypertrophy is in response, and it's that hypertrophy that starts to cause the problems.
What we're getting is annular protrusion. So it's pushing into the canal here. And for the most part, because it is slow and because it is minor, we don't see many clinical signs.
And for any of you out there that have any neck or lower back disc problems, you'll know that you might be able to live, periods of time where it doesn't bother you, but then you'll get sudden onsets of pain and maybe even neurologic dysfunction. And that's what we see in these dogs as well, that they can live protracted periods of time, not have any problems, but They can have an onset of pain, potentially neuro disease. The longer this disc sits here, the more likely the spinal cord will start to slowly atrophy.
So once we start to see progressive neuroscience with type 2 disc disease, we know we're in a little bit of trouble, and in that case, with this type of disc disease, we would need to start thinking about surgery. Now there has been some discussion about a type 3 disc disease, and it's actually a misnomer because there were never 3 types of disc disease described by Hansen, but it's sometimes been called type type 3. What this actually is, is a nuclear extrusion similar to type 1, but this time, the nucleus is still healthy, still hydrated.
So it hasn't had time to degenerate, in which case it's usually a larger breed dog that we'll see this in. It can happen in any breed, but usually larger breed. And.
With some trauma, could just be jumping up and down, jumping off, off a, a bed, a sofa, down the stairs. So with some trauma doesn't have to be dramatic, then we'll get this extrusion popping out. And ultimately, because it's jelly, jelly like, hydrated, it's non-compressive.
But it hits the spinal cord and causes contusion again, right? So we get extrusion of the discs. So here's a nucleus pulposis in situ here, smaller than its neighbours because it's lost a piece, which is extruded upwards.
And it's caused within the spinal cord. This hyperintensity here. This is, ischemia now inside the spinal cord because of the force at which it's hit the cord.
And then outside, we see just a bit of a mess out here. Spinal cord has this. Bright white signal inside it.
That's the ischemia outside, a little bit of a mess, but not really compressive. Look at how round that spinal cord is there. So not very compressive.
So it's not technically a surgical disease. We'll see this in large breed dogs suddenly have an onset of neurologic dysfunction, maybe fairly very significant, maybe that they're severely weak or paralysed. With a little bit of pain at the start, they may yelp out at the start, and then with minimal pain, on examination, as, as, as, as time goes on, that's because again, there's nothing compressive here.
So many times this is dealt with as a medical disease and looks very similar to fibrocartilaginous, emboli, an ischemic myelopathy. How do we tell the difference? Well, the only way is really on MRI to try to look for a bit of material in this epidural space.
But if we don't have the ability to do MRI, We're faced with a large dog with acute onset disease that's not very painful, and top of that differential list would be both acute non-compressive nucleus pulpo extrusion and fibrocartilousembli, and both of them respond the same way to medical therapy. It's determined by your neurological exam. And so if they still have good pain perception in their limbs, good no deception, as it's termed.
Then they have about 80% chance of recovery with supportive care. So it doesn't really matter if you are an acute non-compressive nucleusorposis, or you are in a, an ischemic disease, then your recovery is about the same, so it's not essential for you to know what you're dealing with. Now, if you had a large breed dog who was acutely recumbent and was in a lot of pain, well, that's when imaging probably is going to be necessary.
Just in case this is a disease that would need surgery or needs a, more aggressive, specific therapy. So we have a grading system for our spinal dogs that varies depending on who you read, but we'll, we'll use this as an example of grade 1 through grade 5. And this isn't just purely some academic purpose.
What we have here is an ability to monitor a dog and also provide a prognosis to the owner as well as, as we'll talk about, determine whether medical therapy or surgical therapy is warranted. Grade 1 pain only. Grade 2 ambulatory paraparesis.
So you can still walk, but you've got a notable weakness. Grade 3, non-ambulatory paraparesis. So you've still got movement in your limbs, but you cannot stand up without support.
Grade 4, paraplegic. Sorry, grade 4 paraplegic. So you have absolutely no movement in your limbs.
And grade 5, the same paraplegic, but this time you've lost deep pain perception, sometimes called nosisception. So now there is no evidence of . Pain perception when you squeeze the digits laterally, medially, and even the tailhead area, you've completely lost the ability to feel, and that's the worst scenario.
So that shows us progression of our dysfunction from best to worst. And we'll show a few videos to help us out with that. Here's a grade 2.
Remember, ambulatory paraparesis. So, ambulatory paraparesis, you are able to walk, obviously, but little bit weak, and you'll see on the turn that that's often accompanied by a texture or in coordination there. So we have some weakness.
We have some ataxia, so that's more classic and usually if it's a trac a lumbar problem, your front limbs will be normal, your back limbs will be the ones that are affected. So that's our grade 2. Grading system is not perfect, because as you can see in this dog, he's worse than the grade 2.
But he's not quite a grade 3. Remember, grade 3 non-ambulatory paraparesis. You can still move, but you can't stand up.
So he can stand up a lot worse than that first dog. So, he kind of sits in between. So, so it's not perfect, but Get an idea of where these dogs sit in their progression.
OK, so that's edging towards a grade 3. You can still move more profound ataxia, more profound weakness in these patients. So we look towards then grade 4 or 5, and this is where you have no movement at all, you're paraplegic or paralysed, same thing.
Here we can see no motor function at all. Front limbs look good, back limbs, nothing. Now, this dog could be a grade 4 or 5, and it is crucial in this dog that we try to find out whether he's got pain perception.
The lack of pain perception gives us a grade 5, and that is a poor prognosis, as we'll start to talk about here. So we're really interested in this dog, the dog that's lost all motor function. So whether he can feel his digits.
So we'll really have a look at that in a second. Couple of things to also look at here, as well as this loss of function. You can see he's quite flaccid there, and he's got a lot of tone in the thoracic limbs, a lot of tone.
And when we turn him on his side, you'll see that he's very rigid in those thoracic limbs. That's sometimes called schiff Sherrington posture. And shifts Sherrington posture means nothing apart from the fact it's an acute.
Theracalumba lesion. Doesn't tell you what prognosis is. So here, look at that rigidity that we've got there in the front limbs.
A lot of tone there in the back limbs paralysed. That's shift Sherrington, all that means is you've got an acute thoracol lumbar lesion. It doesn't even really tell you what it is.
Just as acute. What we're interested in though in this dog is can you actually feel your toes, right? So we could pinch with our hands, and if the dog responds, gets a message up to that brain, and he turns around, tries to bite or screams, vocalises in some way, then we'll say, OK, you can feel.
But it's so important to test that if he doesn't do this with the use of fingers. We're gonna actually squeeze with a tool of torture. Now, he's moving his leg here.
That's a reflex. Ignore that because at this stage, we are now looking to see whether that message passes all the way up to his brain, and he turns around or vocalises. And we don't see any in this dog seems completely unaware that we're doing this, and we could pinch lateral digit, medial digit, tail head, and we need to see if there's any behavioural response.
What we're testing for is, does a message go from those digits, up the leg, up the spinal cord to the brain, right? So, two things happen when you put your hand in, in a, in a flame. You want is you pull your hand back quickly.
That's the reflex. The next thing is you go, Oh, that was hot, and that's your conscious awareness of, of the pain. That's what we're looking for in this test.
Conscious awareness. We don't care that the leg pulls back. Owners may say, oh, look, he's moved his leg, but that's just a reflex.
It's not voluntary. We're looking for awareness that you feel that pain, because if you do, that means some of your spinal cord is still working. If you don't, then we may have very serious amount of spinal cord injury.
Now, in that situation, grade 5, where you cannot feel your digits, it's pretty bad, and we'll talk about prognosis shortly. But it's not the worst, unfortunately, because that can get worse over the next 72 hours. That's gonna be our critical time, because we may have this dog experience progressive myelomalacia.
What that actually means is liquefaction of your spinal cord. So any dog who's paralysed. And cannot feel their digits.
And we have a dog who's at risk of progressive myelomalacia. It happens to be about 10% of those dogs will experience this. So if you have a dog who is paralysed or paraplegic, lost deep pain sensation.
Then 10% of those are at risk of this liquefaction. What does it look like? Well, it's an onset of profound pain, more pain than you'd really expect for this disease, and it doesn't really respond very well to our usual analgesics.
They're very hypothermic, they start to tip the scales a little bit above 40 °C. That's gonna be a worry with this disease because normally disc disease should not affect your body temperature. Your cutaneous trunci reflex ascends.
This is a, a, a reflex that we perform sometimes where we pinch the skin lightly up and down the back, and we'll see a ripple of the skin associated with that. And that can help us mark out where there may be injury. And so we'll see that actually move towards the shoulder blades.
And also, we'll see a loss of reflexes in the pelvic limbs, loss of anal tone, and ultimately a loss of continence and ability to breathe. So a respiratory drive, and some of these dogs will have a respiratory arrest. Some that progress will force us to make a decision about euthanasia on humane grounds.
Unfortunately, this is a permanent sign. If the if the mala malasia actually stops prior to causing a respiratory arrest, then this is something that has now permanently damaged the spinal cord, and there will be no improvement from that. Level of neurologic dysfunction.
So something to watch out for and warn the owners that if you cannot feel your digits, then that's a serious situation, but it may even get worse in 10% of cases. So just again, a quick review of type 2, this disease, because we've been talking about type 1, the extrusion, the acute scenario. Type 2 is in our larger breed dogs.
As we said, it may not be painful. This is because it's a slower, chronic protrusion, where The disc starts to push up, and here where we see a myelogram, where it's the best way to show us that subarachnoid space around the spinal column here. It thins out over the disc space because it's just been slightly pushed upwards.
Now, the more compression. The more likely we'll see some pain, the more likely we'll see some neurologic dysfunction. But many times, just like in people, they can live out their lives and not have too much problem.
This is a slow degenerate age-related change, but they can present with these acute on chronic episodes. So if they go out and decide To run around the garden or play frisbee, then all of a sudden they may come back in with back pain. And this can be just as in people, resolved with a few days of rest, analgesics, anti-inflammatories, just a few days.
This is different from our type one, which we're going to talk about shortly. . It's also the type of disc, type 2, also the type of disc that is sometimes accompanied in larger dogs by a type of narrowing of the spinal canal called virtual stenosis in the neck, that can be sometimes called wobbler's disease or cervical spondylomyelopathy.
In the lumbar spine, that can be called lumbar sacral degeneration. Again, a multitude of terms to describe disc disease as well as a stenosis of the canal. So sometimes not only is disc removal with surgery warranted, but maybe some type of stabilisation or, opening of the canal to take away the, respectively, the movement that's going on there, or the stenosis.
That's type 2 disease. So we get back to type 1. Many times we make a presumptive diagnosis based on who you are, how old you are, and what you're presenting with.
So if we see a 5 year old dachshund, for instance, then it's no surprise that if it has an acute onset of neurological weakness, and it's painful that we would put this disease way up there, #1. 95% of the time, at least, you're gonna be right. We have to think about is there a possibility of trauma, to any chance of fractal luxation, infections, inflammations.
This could be discosondylitis, meningitis, anomalous disease. So we'll see in a French bulldogs, for instance, that they have vertebral malformations. That might lead to stenosis of the canal, that might lead to kyphosis, so a type of deviation of the spinal column.
We see similar things in pugs as well. They rarely cause acute onset of pain, but they can predispose to disc disease, and they just complicate the clinical picture because, taking out the disc on its own may not be the only thing we actually have to do. And then ultimately, obviously, any older dog with back pain and weakness, we'd have to think about tumour.
But 95% of the time, we can make a pretty good dealing with disc disease. If we want a little bit more information, then we start to think about tests that we could do. And obviously, we immediately start thinking about .
Imaging and radiographs would be a good first start, if we're suspicious about, about this disease, but it's probably best to use them to rule out other things. So most of the time we're ruling out disco spondylitis, trauma, lysis. From a tumour, rather than disc disease itself.
This disease we may see show up on a radiograph as a set of signs that include mineralized disc, narrow disc space, maybe a more a pacified into vertible foramen. Sometimes smaller. Into our particular spaces.
Here we see a bit of a crescent moon that's a joint space here, maybe a bit smaller here. It's kind of in the eye of the beholder. Well, if this is in a dasund, it's no surprise that we're seeing signs of this disease because that's what they're genetically programmed to have.
So the fact that we see this on a radiograph isn't really helping us too much. 95% of the time we've guessed it's this disease and we'll be right. And so taking a radiograph.
Doesn't help us too much, because we're really looking to prove what disease is, is there, and also where it is, and, and radiographs on their own don't do a great job of telling us which disc is in the right place. Maybe 6 out of 10 cases, you'll be right. So you might have this disease here, 6 out of 10 times, that's the correct place in that individual dog.
Well, that's not good enough if you're ultimately going to take the dog to surgery. So we need better. Now, it's still performed in, in some places, we have myelography, where we're putting some contrast material in the subarachnoid space, and we can then see indirectly that there's something outside the spinal cord here, because we can see that contrast column lifted up over that disc space.
So we were right in saying that this is disc disease, and in this case, this is causing the problem. You can see it lifting up and over. The accuracy of myelography, varies really, anywhere from sort of 3/4 to just under 100% certainty of whereabouts in the spinal cord cord it is.
So here, we can see that we've got this is C6, C7. So we can see, OK, that's lifted up there on one side. So we'd be pretty confident that's the problem.
We're less confident in many cases, which side. And so in the rack a lumbar column, we need a bit more information as to what side it's on. Sometimes it can provide some prognostic information.
If you're deep pain negative and we see some spinal cord swelling that's 5 times the length of, of L2, then the chances of you recovering are minimal. And occasionally, in addition to swelling, we may see evidence of myellamalacia. An old paper here that shows that instead of two nice tram track lines, railway lines of contrast, we've just lost it completely and that contrast is now inside the cord, and this is indicative of a breakdown of the structure.
And so myelomalacia may be seen on this type of examination. Many times now we push advanced imaging to give us a little bit more of a three dimensional assessment, which helps us out. CT examination is obviously is obviously radiograph based, but gives us this transverse appearance that may help us lateralize the disc.
And because it's a radiograph, in essence, then we're looking for mineralized material and many times that The disc itself is mineralized with degeneration. So we can see in this dog, we have bony material within the canal. You can see that here.
And so we were able to see that we've got disc, in the canal, mineralized disc. We also did a myelogram in this case, you can see. Nice spinal cord there, and then the contrast doesn't get past this obstruction, which is the extrusion here and on the other side of it, we can see it coming back.
So sometimes myelography and CT will go together, if the extrusion is not particularly mineralized. But if it's mineralized, then CT on its own can do a pretty good job, often seen as the Poor relation to MRI. It's not quite true in many cases.
It can do a great job with this disease. It's cheaper, it's quicker, and you can scan the whole spine in a short period of time, as opposed to MRI where it takes you over an hour for just one section of the spine. But MRI, as we know, is very sensitive for depicting parental change.
So not only looking a little bit of the bone and the disc outside the spinal cord, but we can see changes inside the spinal cord. So here we can see nice image of the spinal cord surrounded by spinal fluid and epidural fat. And then we see this monstrous lesion here.
That's the same kind of density, or intensity as our bone. And so this is then disc extrusion pushing up on the spinal cord, and we also see changes inside the spinal cord which can be haemorrhage, which can be edoema associated with the trauma. If we do cross-sectional imaging using MRI again, just like the CT cross section gives us a better appreciation of just how much disc is in the canal and what side it's on, and so it can really help us with surgical approaches.
So MRI in this case shows us that disc is very lateralized and shows us that the spinal cord is really compressed quite dramatically so there. So can be very helpful. So, so we rely on that advanced imaging to tell us what the disease is, where it is.
In the spinal column and some lateralization, as well as how severely affected the spinal cord is. But the neurological exam is key, really. We're never ultimately going to rely on imaging to tell us how well this dog is gonna do.
We're always gonna look at the neurological exam. So we come up with then treatment options in these cases. 95% of the time, you are correct in guessing that it's disc disease.
And so we could move without imaging if the owners can't afford it right now to to determine should you go to to conservative therapy. Or surgical therapy, likely if they can't afford the imaging, probably can't afford surgery. And so we discussed the rights and wrongs of conservative or medical approaches here, and try to come up with some criteria for which dogs will benefit from it and which dogs must go to surgery.
So, when we talk about medical management strategies, there are multiple factors that get taken into consideration. primarily, neurological status, which we're going to focus on. And obviously the economics involved, so how much money the owners have.
There are other things, how long has it taken, for this disc disease to, to cause its signs or to progress? Has there been any other medical treatments employed? Have there been multiple episodes seen.
Over the last few months or years? Is it neck or back? What type of tests have you used?
So there are other, other factors to take into account if you're thinking about a medical therapy versus a surgical therapy, but primarily it comes down to how severely affected are you and how much money do the owners have. And we're looking, when we talk about, comparing medical therapy with surgical therapy, we're looking at. Which dogs will make a successful recovery.
So, so we really should define successful recovery. May go without saying, but it includes an ambulatory gate without assistance, so you can walk. But it's important to emphasise to the owners that there may be permanent damage.
Your dog may be able to walk and recover from this, but that you may see some changes in the gait, some weakness, some, some in coordination. But that should be non-painful. So they'll be functional and they'll have a good quality of life, non-painful.
And in addition, should have urinary and faecal continence. Right? So that's our aim.
There's a set of aims for success in these dogs who have disc disease. If we manage them medically or surgical. So when we say a certain percentage success, that's really what we're aiming for.
So let's look at that success with conservative management, a medical approach to this disease, based on the grade of dysfunction that you have. So again, this grade system we talked about, grade one is pain. You have a 90% success rate if you have conservative therapy.
Seems pretty good. And then you get a little bit worse, grade 2 ambulatory paraparesis, 90%. This is just across the board looking at the literature, and some, some experience that we have, grade 3.
You can't walk now, but you do have still some motor function in the limbs. We'll treat you medically 70% chance of success. Grade 4 paralysed, paraplegic, 50% success, 50/50.
So if an owner doesn't have any money and their dog is paralysed, they still have a reasonably good chance of having a successful recovery. However, if that dog has lost deep pain perception or no susception, then with medical therapy, less than 5% chance. So there is a concern there, and this is our first criteria really, that starts to develop for, for indications of surgery.
And you'll see this when we hop over to surgical management here. Again, grade 1 and 2 have a 90% success rate with surgery. So similar to conservative, why would we really do surgery on dogs that have back pain or just are weak?
So we must be missing something there. We'll talk about that shortly. Non-ambulatory paresis, a little bit better of a prognosis.
Remember with medical therapy, it's around 70%. If you can't walk, 90% here, if you do surgery. But paraplegia, this is where surgery comes into its own 80 to 90% success rate with paraplegia.
Compared to 50/50, if you're medically managed. And then if you've lost deep pain perception, time dependent, some, some contention in the literature here. But many times, people will say, 24 hours, maybe up to 40 hours, 50, 60% here.
After 48 hours starts to dip down, maybe to less than 5%. When does it become zero? No one really knows, but Most of us would be comfortable saying, if your dog has had no pain perception for 7 days, the chances of a good recovery now are extremely low, as close as they could be to 0.
1st 24 to 48 hours then is vital if you're gonna go to surgery. So, criteria number one for surgery would be if you're paralysed, because surgery obviously does do a better job of improving your function. However, if you still have motor function, medical options are still present for you.
Criteria number one, you're paralysed, you must go to surgery. So let's move on. When we talked about medical therapy, we've got to try and articulate what this is.
And it used to be, high doses of steroids, for spinal cord trauma, for disc disease. So it's worthwhile mentioning where did that come from and why we don't use this anymore. High doses of steroids means, we used to give parental IV, methyl prednisolone, sodium succinate, sodium-Medrol, so, variations of this.
And we'd give them at 30 milligrammes per kilogramme, so 30 times an anti-inflammatory dose. And this was because in the, in the 80s, 1980s. In humans, it was shown that methylprednisolone has qualities, outside of just being an anti-inflammatory medication.
It was shown to mop up all of those chemicals that we pointed out in earlier slide that include the oxygen radicals, accumulation of calcium. And some of the neuro excitatory transmitters. So it was shown to do a great job, and it did that at 30 times the anti-inflammatory dose.
So in people that had spinal cord injury, they were given this protocol where 30 mg per gig was given within 8 hours of the injury, was repeated at 15 mg per gig at 2 hours, 15 mg per gig, 6 hours, and then every 6 hours. And they were given various types of protectants. And so this protocol made its way into veterinary medicine as well.
But there are some problems with it. Problem number one is if you didn't give it within 8 hours in people. It was actually, deleterious to your function.
It actually made things worse. And that was meant to be because it interfered with your healing mechanisms. So if you didn't get there within 8 hours, now as a person, many times it's going to be easy to Articulate when that injury started.
But in a dog, when does that clock start ticking, especially when you may see a dog who had back pain last night, it's paralysed this morning. So the 8 hour time frame is a tough thing in dogs. The second thing is, is that it was shown that improvement that was gained by the administration of this in people was minimal.
It resulted in you moving your fingers and toes at 6 months and 12 months after your injury compared to not being able to do that if you didn't get this medication. Well, that's great if you're a person moving your fingers and toes. Particularly if you're a teenager, you can now tweet, Snapchat, TikTok, all of that, and you'll be fine.
But as a dog, you cannot, really function if it's just going to enable your digits to move. And then thirdly, it was shown that people that got this medication spent longer in intensive care with respiratory problems, pneumonia. Secondary to the use of the drug, and although we don't see that in vainary medicine, we do see gastrointestinal issues related.
And so it became really a problem that with lack of functional recovery seen in humans, further investigated in dogs and shown that really didn't benefit dogs in any functional way. And cause problems where the risk benefit analysis said, no, we don't use high doses of steroids anymore. That has sometimes been misinterpreted to suggest that we should never use steroids with spinal cord injury and this disease.
And that's not quite true, because there is obviously inflammation present, and especially 23 days after the injury, inflammation takes a massive role in the pathophysiology of spinal cord injury. And so inflammation should be addressed in some way, shape, or form. So we do think about using either nonsteroidals, or if you do want to use steroids, low doses of them are where we would go, half a mg per gig per day, so anti-inflammatory, up to 1 mg per gig.
And for a short period of time, right? Because when we're talking about inflammation, we're talking about it resulting from a hit to the spinal cord. So this isn't going on for weeks.
This is going on for several days at most. So we think about using these anti-inflammatories for just a few days, whichever one you want to choose, we're obviously not going to combine NSAIDs and steroids. It's whatever you would like to do.
Sometimes some dogs are not responsive to non-steroidals, so we may think about going with low dose steroids. But we use one or the other. And then we also go with muscle relaxants, muscle relaxants, are vastly underutilised for back and neck pain in dogs.
But if you've ever had, neck and back pain, then you'll know that a lot of it can come from muscle spasm. So muscle relaxants can be very helpful as part of the cocktail for treatment. In addition, we may use something like gabapentin or even pregabalin.
As it becomes a bit cheaper on the market, which is a miscellaneous class of analgesics, helps with neuropathic pain. And we've got various types of pain going on in these back dogs. We have no ciceptive pain, which is where something is really pressing on the spinal cord and irritating the meninges.
We have neuropathic pain where the nerve roots are involved. We have inflammatory pain. So we, all of those causes of pain need to be addressed.
So, we often will go with a muscle relaxant, an anti-inflammatory, and maybe gabapentin or pregabalin. Occasionally, if the pain is really severe, we may think about going with an opioid. However, all of these things, have to be used in conjunction with a period of strict rest.
And the reason for this is that there is a lot more of that nucleus still in, in situ, in many cases, and some of it can come out of the hole that is in the annulus. So, in those cases, strict rest is to enable healing of the annulus fibrosis. We need that healing to take place so that we don't get further extrusion.
So if we come back to that donor analogy, we need that hole to heal up, otherwise further jam is gonna come out of the centre, and it needs to be 4 to 6 weeks. And this is a problem because these dogs may look great after 2 or 3 days on this medication, but unfortunately, they need strict rest for the healing to take place. So this is our medical therapy, and we know that it's going to be successful in some cases, and we then have to question, well, why would we ever do surgery?
Because, you know, we have some cases which, are either back pain only or some paresis and ataxia. Why with 90% improvement on medical therapy, would we ever consider surgery. And so we come with this now analogy, of 4 Daxunds and what happens, statistically speaking, with these Dachshunds.
However, we've turned them into pigs. So it's the story of the 4 little pigs, but this is the story also of the 4 dachshunds, and, and this is statistically roughly what happens when we treat them medically. Because we're always gonna get a question as to how we should treat these patients.
We know a cri criteria number one for surgery is if you're paralysed, but we need to develop some others. So this is the story. 4 of them come in, they all have back pain, and you decide that you're going to treat them medically.
So, pig number 1 gets medical therapy. That's the strict rest and medicine cocktail. And we treat that that dog or pig medically.
Any girl leaves your practise, goes off into the mountains, lives forever, does great. 25% will never recur. Positive response.
Pig number 2 and 3 say, oh, we would like a little bit of this. And so they get treated medically, and they also do great. Cause remember, up to 90% of dogs will do great on medical therapy.
So they run off and come back, unfortunately, within a period of time, so one, within a year. Within 2 years. And this highlights the problem of medical therapy long term, and that is that 50% of cases will recur.
Now they may recur with just back pain, and maybe you want to manage them in a similar way, but they may recur with more severe neurologic dysfunction. So that is the problem. And then we've got the final dachshund or pig here, gets treated medically and walks, tries to walk out, he's paralysed very quickly, unfortunately.
Within 72 hours, because remember, ischemia within the spinal cord can progress quickly. And so this is a a dog pig that comes in to see you. And has back pain and gets treated medically.
And whereas the other three did great, this one doesn't do great. And unfortunately, we don't know which one it is, right? Oh, that's inappropriate.
But, we don't know which one it is. We can't tell the owner, your dog will be #4, will not do well. And so we've developed a few other indications for surgery here, and those are, in addition to paralysed patients.
There's those that are recurrent. So if you come back within a few months or a year, we should start thinking that you might need surgery, because this could go on and you could have then a deterioration in your clinical signs. If you don't respond to medical therapy.
You remain refractory, so your back pain, for instance, stays, present, you need surgery. And like pig or dog number 4, if you start to deteriorate over the course of your medical therapy, particularly in the first few days, you need surgery. And so are the criteria.
It's difficult if an owner says, well, Still don't have any money. But if an owner says, well, I'm prepared to go either way here, then, absolutes really are, if your dog is paralysed, should have surgery. If it's recurrent episodes should have surgery.
If it's refractory pain, should have surgery, and if you're deteriorating neurologically, you should have surgery. That's not to say that a dog, first time offender with back pain, shouldn't have surgery. That's the owner's decision.
But they should be appraised with all of these facts, and then can determine what's right or wrong for them. Important to note that part of your medical therapy, whether you've had surgery or not, is always going to be the supportive care, the bigger the dog, the more effort that needs to go into this to try to prevent the dog, from picking up things, from getting things which it never had, at the time of presentation. And these can include urine scold, urinary tract infections, aspiration, pneumonia, contractures, and the like.
So we try to do several things to prevent those things. We try to make sure we're providing, obviously, a lot of bedding to stop them getting pressure sores, their cubital ulcers over bony protuberances, try to make sure they're turned regularly. Put in a non-slip mat in there if they start to try to stand up.
Sometimes we'll use water beds, again, trying to really cushion them because they're spending a large period of time down. This is most important in our larger breed dogs. .
We might have to assist them with feeding to prevent aspiration pneumonia, and also bladder management. This becomes important. If you can't walk, you can't urinate voluntarily and efficiently, and so we may need to help you out with that.
That may be light expression, but if expression causes pain, It's difficult to do, and medication doesn't help relax the bladder anatomy to help us. We may put an indwelling urinary catheter in. And for the first few days, I find this essential.
It really helps out nursing these patients. It takes some of the workload off your team. And makes them feel a lot better because they're not being pressed on all the time, particularly after a surgery.
And in the first few days, say 3 to 4 days, it does not seem To cause or predispose to urinary tract infections. Any longer than 3 or 4 days, yes, we start to see a rise in the potential for urinary tract infection. But if you cannot walk, you are now predisposed to a urinary tract infection regardless.
We don't want to put one of these in place if they're on antibiotics, encouraging a resistant antibiotic growth in there. But it is important to stress that if you can't walk, you can't urinate efficiently, you will develop a urinary tract infection. And so that's gonna be part of our focus of medical management.
Physical therapy, hydrotherapy, so rehabilitation therapy, always gonna be important. Some evidence that it may speed up. The improvement may not change the overall outcome, but may speed up the improvement and enhances quality of life and comfort and improves muscle mass circulation to support the regeneration that has to occur in the nervous system.
So in summary, this disease can be acute or chronic. And that classically is type 1 or respectively type 2. Different path physiologies give rise to these clinical signs, and it's the type one disease that we struggle with the most, because we have to make a decision as to whether you are medical or a surgical.
And unfortunately, our medical approach is really more of a supportive symptomatic. Approach, rather than anything more specific, because we haven't got any medications that will specifically target those pathophysiologies yet to help us improve our outcome with spinal cord disease. Always need to remember ruling out other diseases is essential, and that's the reason for sometimes we'll go to advanced imaging, but most of the time, we're in our chondro dystrophic dogs, we're going to be correct in assuming it is disc disease and that We can start having conversations with the owner about medical versus surgical management.
Ultimately, whatever tests we do, the prognosis is determined by the neurological exam. And so we can give some ideas to the owner about what a successful recovery is, and the chances of that being achieved with medical and with surgical therapy. And that's the end of this session.
I thank you for your attention and would be happy to take any questions. Thank you.