Hello, my name is Louise Starwood, and I am a large animal emergency clinician at New Bolton centre, which is the large animal hospital for the University of Pennsylvania, and I just like to to thank everybody for the opportunity to present this lecture. So I'm gonna be talking to you about management of wounds and lacerations in horses and other than colic, this is one of my most favourite topics to talk about and one of my most favourite types of cases to see. So I'm just gonna start with an overview.
Of emergency management of lacerations, and some of these aspects I'm going to go into a little bit more detail with as we go through this lecture. The first and foremost thing is to stop any severe haemorrhage. Now haemorrhage is fairly uncommon in distal limb.
But it can if the animal is allowed to bleed for a long period of time, they can have issues with blood loss. And we're going to talk a little bit more about that, how to stop the haemorrhage, how to decide if the animal at some point needs a transfusion, and, and what that might look like. Once you've got any sort of potentially fatal bleeding stopped, you want to assess the animal for any lameness or gait abnormality, and it's important to do this before you go ahead and block them because if the animal is severely lame, or if have some sort of tendon or ligament injury, it's important to know that ahead of time.
And examples might be a non-displaced fracture can make the animal be disproportionately lame compared to the laceration. And another example is animals with transaction of their deep digital flexor tendon, you'll often observe that they will flip their toe up or hyperextend, I guess their distal in a phalangeal joint, as they're walking. Before you do, go ahead and sedate the animal give them any drugs, go ahead and do a physical examination.
While blood loss may not be, necessarily immediately fatal in these cases, they can have some degree of blood loss, and early signs of shock, and also a lot of times these animals are in a lot of pain, they've been sweating, and so just briefly at least assess the cardiovascular system, before you go ahead and sedate them. If I'm dealing with anything other than a very, very superficial wound, I go ahead, after I've examined the patient, I go ahead and sedate them and then infiltrate the area with local anaesthetic, and this may be a regional nerve block or it may be actually infiltration of the wound, specifically. What I've found is if you start evaluating.
And probing a wound, the animals, the animal becomes painful. And even, and then when you go ahead and sedate and block them later, they still respond. And so it can be more difficult, to manipulate that wound, kind of, even once they're sedated and blocked, they'll still kind of, withdraw the limb.
And so I think getting analgesia on board early. Getting, the area desensitised, then you can do a proper evaluation of the, of the wound. What I do is I put sterile lubricant in the wound.
Yes, most of it falls off, but it still puts a nice coat over that, deeper tissue to prevent hair sticking to it, which can be incredibly difficult to get out of the wound, if you don't do that. And then I go ahead and clip and prep, clip and prep the area, clip and prep the wound. You wanna avoid any soap, any, any alcohol, being, put in the wound.
And then usually what happens at that point, if the wound has been bleeding, once you go ahead and clip and prep it and get it all cleaned up, what actually happens is it'll start bleeding again. So then often, you may have had the bleeding, stopped, with a bandage, or the owner may have had the bleeding stopped, with a bandage once you go ahead and start manipulating it. Or it can often start bleeding again.
So we'll talk about a little bit more about how to stop the bleeding, once again. And then I, I spent quite a bit of time, exploring the wound, palpating the limb to try and work out. The goal with this is to work out what deeper structures are involved in any time.
You have a laceration of the distal limb, there's almost always some bone, tendon, ligaments, something, joints, synovial structure, involved, and I'm gonna go into a little bit more detail with that as we go through this lecture. Once you've assessed the deepest structures, you know, and once again, this is just an overview, go ahead and lavage to bride the wound, and I almost invariably close the wound, except if it's, you know, a chronic wound. I do think that they heal quite a bit better, even if a synovial structure is involved, and even if the wound, quite frankly was quite dirty, I still go ahead and close, do a thorough debridement and close it and.
We're gonna talk a little bit more about approaches to wound closure, but I will tell you, I spend a lot more time debriding the wound than I do closing it. I make sure that at least to the best of my abilities that that wound is thoroughly debrided. I usually do a piecemeal debridement, which, I, I almost never remove any skin unless it's clearly dead, especially from the distal limb, but I go ahead and remove.
Any tissue that's contaminated or severely traumatised, I go ahead and remove that using a piecemeal approach. And it's really important to make sure you get into any pockets in the, in the laceration and make sure there's not, dirt, packed into those, pockets. And sometimes what I'll do is I'll very, very gently get a curette and just, gently curatete those pockets to make sure I've removed all, the contaminating debris.
Then we usually bandage it, animals with especially distal wounds, distal limb wounds, but really any wound should be confined to a stall or a stable, until, that wound has healed. Antimicrobials, a lot of the lacerations we see, have, some sort of synovial structure involvement. However, really think about for some of these wounds, that don't involve bone or any synovial structure, You know, for example, if it's a wound on the upper, on the upper limb or the upper body, that really, maybe it's not particularly deep, does the animal really need any microbials?
What are the consequences if it does develop an infection, what are the consequences, of that infection occurring? A lot of times the wound's gonna heal. Anyway, might take a little bit longer.
And so really think about does the animal need antimicrobials? And I've really tried to decrease the duration of antimicrobial drugs, that I use on my wounds. And typically, I keep them on therapeutic antimicrobials until that wound, stops draining.
Non-steroidal anti-inflammatory drugs either Floex and meglamen or phenybuasone. Obviously, at least in the emergency situation, we're going to use them for analgesia. I do think, and they're an important part of wound management, to decrease the inflammation and, to provide the animal with some pain relief.
However, I do think you need to be careful as I, I don't. Leave these animals on for a particularly long period of time, because especially if a synovial structures involved or bones involved, I want to know sort of at that 4 or 5 day mark, am I getting an infection, you know, do I need to, do I need to be doing something else such as reculturing, the wound, reculturing the synovial structure. doing some sort of, arthroscopic, tenoscopic procedure, to further treat it.
So I'm pretty conservative. I want to provide analgesia. I want to decrease the inflammation, at the site of trauma, but at the same time, I don't, I wanna be able to assess the animal, the animal's level of pain.
We've also got to be careful, I mentioned some of these animals can be fairly, you know, can have signs of shock, and so you've got to be Be careful with non-steroidal anti-inflammatory drug use in animals shot because it can cause renal failure and so, I should say acute kidney injury. And so monitoring that really closely and, and, monitoring, for example, creatinine concentration is, is important. We're gonna talk a little bit about radiographs.
They can be obviously important for assessing bony damage, but it can also be really useful for assessing whether or not they're synovial. Fluid involvement. And one of the key things for prognosis, I think a lot of these animals, depending on the degree of, injury, can actually do really well.
And we'll talk a little bit about if a synovial structures involved, it's absolutely critical, to recognise that early and treat that animal appropriately early, because if it's left to wait till an infection is established, the prognosis for survival and especially athletic performance goes down quite a bit. So I've already talked to you about haemorrhage a little bit, in the overview, but it's obviously really important, you know, to stop haemorrhage. And even though life-threatening haemorrhage, it's fairly uncommon, in animals with distal limb lacerations.
Obviously, if there's a laceration of the, the neck and the jugular and carotid artery is involved, that's a lot. More serious, but the distal limb lacerations, which are a lot more common, can, usually it's life-threatening haemorrhages uncommon. However, if that animal is allowed to bleed for a long period of time, they can develop signs of hemorrhagic shock.
So the, best way to do it is, apply digital pressure or a bandage, some sort of pressure over that, the site of haemorrhage over the wound, is often very effective and especially in an emergency situation until you can get the animal to a place with better light, or maybe have it anaesthetized and . And, you know, and evaluate to be able to see the vessels, to ligate the vessels better. And this is, this picture here, these, these are the type of lacerations that can actually bleed a lot of these distal limb lacerations.
You got a plexus around the coronary brand, you've got your palmadigital artery and vein that can also bleed. This animal here, with a past the laceration, It, it, it wasn't, it was bleeding at the time of presentation. And, however, we, had a nice bandage on it.
We took this animal to surgery and it wasn't bleeding during surgery. I do, I do not use a tourniquet at surgery, so, it was not fun. And then this is what this animal looked like, in recovery.
Obviously, it started bleeding again, from a relatively, relatively minor laceration. So, and what I do in these cases, we've already done surgery on this animal. There were no obvious vessels to ligate.
Obviously, there was what was, and, we didn't find it. What I did, it was obviously bleeding through this bandage. I went ahead and put another bandage on and I, and I put layers and layers of bandage until that bleeding, stops.
And usually you can get it, usually you can get it to stop bleeding in this case. We did not re-anesthetize this animal, but the bandages and we, we got this, to stop, and, the animal ended up healing the wound, and was fine. And so vessel ligation is obviously ideal.
A lot of times, you know, this is a heel bulb laceration that may or may not involve the Palmer digital vessels. A lot of times what I do is if I've got one of these lacerations, you can put a tourniquet on. What actually works quite well, for ones below the fat like is you can get some 4x4 or sponges and roll them up and then just put them over.
The abaxial aspect of the sesamoid and wrap them around with some vet wrap, and that can give you enough hemostasis so you can actually identify the vessels and ligate them, and you can ligate them with some sort of 20 absorbable suture material. Sometimes you actually have to, unfortunately, make the wound bigger to get access to a vessel, . Because what happens when that vessel is transected, at the time of trauma, it retracts.
And that's part of, you know, the, the, response to vessel injury is to contract, to try and provide hemostasis, and, and that can make it the vessel difficult to access through the wound. So usually we do this with the animal and the general anaesthesia and it's usually cases that, you know, are persistently haemorrhaging, but just be aware of that sometimes it's not always that straightforward. So obviously ligation is ideal.
Ligation is, you know, is the, is the best method, but at least in an emergency situation, if the digital pressure, sometimes just putting pressure on it or bandaging, can be ideal. So one of the challenges is that whenever an animal bleeds, it looks like a lot of blood, and especially to owners, . Just making them aware of how much blood the horse actually has, it can help them think more rationally in an emergent situation and get a bandage on that animal, and not be overwhelmed.
So the 500 kilogramme horse, 8% of the body weight, they've got about 40 litres of blood. The thing is, which is a lot, the thing that is concerning is they, only the clinical signs of blood loss to, to be seen, so the signs of shock to start to develop, they lose about 25% of that. So that's about 10 litres.
Which is also quite a large volume, however, they can bleed a lot quite quickly, or they can bleed a modest amount over a long period of time and, and you can get to that 10 litres relatively quickly. The thing that's always concerning to me is death can occur when you're approaching, you know, about 40% of that blood volume. So that's only an additional 6 litres.
So that's about 16 litres in a 500 kilogramme horse. So the reason to present this, the key thing is horses do have a lot of blood. They need to lose a lot of blood, before they start showing.
Clinical signs. However, when the time between when the onset of shock, starts and the clinical signs of blood loss start to when they could die, it's, it's, it's a relatively small, small volume. So it's obviously, important to monitor them closely, to stop the bleeding, monitor them closely, and think about, does this animal need a transfusion?
And so here's some transfusion triggers, PCV less than 20% in 12 hours, PCV less than 12% in 1 to 2 days, ongoing haemorrhage, and that's when your, haemoglobin gets less than 50 grammes per litre or 5 grammes per deciliter that, you decrease your tissue oxygenation, oxygen delivery, and we talked a little bit about that in the lecture of assessment of the emergency case. Just remember, even though we've got these, PCVs as transfusion triggers, early on in the course of blood loss, because they're losing red cells, they're losing protein, and they're losing water altogether, PCV is not, and total protein is not always a good indicator of blood loss very early on, so that's kind of 4 in that 4 to 12 hour range. And actually sometimes the PCV can be even a little bit high because of splenic contraction.
So just keep that in mind. So then, in that case, you've got to try and assess the degree of blood loss, which can actually be quite difficult. And then you look at other signs that can trigger a transfusion, and so they're your signs of shock.
So we're talking tachycardia. Often horses with a laceration might have a heart rate in the, high 40s, 50s, but if they've got a heart rate, persistently have a heart rate of 80, I would be concerned about signs of shock. Weak pulse.
Pale mucous membranes, and one of the things that's really important is animals with blood loss are often really dull. And then the other thing that obviously we do measure PCV total solids, like I said, that's not always reliable in those first few hours after haemorrhage, but one thing that you will see is an increase in, your blood lactate concentration, and remember that's the end product of anaerobic glycolysis. And so like I mentioned in the lecture of assessing the equine emergency patients.
If you have not got enough, if you haven't got enough haemoglobin, you're not delivering enough oxygen to these cells. And so, they're gonna use anaerobic metabolism to generate ATP and you're gonna have an increase in your blood lactate concentration. So that can be an indication of the need for a transfusion.
In some of these patients. The other thing is hypertension as well, if you can put it, if you've got a a blood pressure, means you can go ahead and put a tail cuff on the animal and measure blood pressure, as well. So all these, you've got to look.
The whole picture, when deciding whether or not, to transfuse an animal. And you may start with some intravenous fluids and then, reassess. One of the things over the past, you know, several years that I've been practising is I tend to, be, if the owner, you know, with the owner's permission, obviously, I tend to be more willing to do a transfusion.
Than what I have, say, 2025 years ago. The other thing that a transfusion can offer you is it can provide some coagulation factors. So if you've got an animal that has lost a lot of blood and maybe potentially has some ongoing blood loss, that those coagulation factors can really help the animal, clot.
So we always debate whether we should do a crossmatch. I think most of the animals that we transfuse now, we do not crossmatch. You can take up to 8 litres of blood, from a donor.
And then, collected into a bag with anticoagulant, and often I, when I'm transfusing an animal, I often give them 6 to 8 litres, or you can give them 50% of their estimated blood loss. Monitor them very closely for a transfusion reaction, so you're looking for urticaria, you're looking for tachycardia, increased tachycardia, you're looking for. Increasing rectal temperature.
I've used diphenhydramine a couple of times per odds in animals, that I have seen have a transfusion reaction, which is actually very, very uncommon. And I've never had to use epinephrine, but if they're having a severe reaction, that would be the drug of choice. And obviously, the key thing is if you do observe a reaction to stop the transfusion, right away.
And don't forget, even these animals, sometimes they've got some modest blood loss. They may benefit from intravenous fluids, you know, if they've got all, you're concerned about coagulation, you know, plasma can help by providing some coagulation factors, and then sometimes the animal really Haven't bled, but they've been, they've sweated quite a bit. They're painful.
And don't forget the enteral route for administering water and electrolytes as well. And I mentioned in another lecture that you know that these these animals' primary problem is their laceration, but sometimes Yeah, I'm secondary. Gastrointestinal complications such as inaction or ileus and so providing with in water and electrolytes can help keep them hydrated and help keep moving digestives through their gastrointestinal tracts.
So don't forget, these other sources and roots of fluid therapy can be helpful. So I mentioned one of the main things, we're always concerned about primarily with distal limb lacerations. It's synovial cavity involvement, and obviously there's bones, tendon, ligament involvement, but a lot of these lacerations involve some sort of synovial structure.
And I mentioned, you know, the prognosis, can be excellent for these animals to, to return to athletic performance, if they're treated early and appropriately and unfortunately, if they're not treated early and appropriately, it can be fatal and this is OK, so I had a long time ago during my residency that locks up here, the hoops down here. It had this, this is the Palmer aspect of the limb. There was a very small cut to the back of the foot and the owner managed it, put some, put some salve on it, put some ointment on it, and unfortunately, the horse presented to us 7 to 10 days later, it was non-weight bearing lame.
It had support limb laminitis, and we ended up needing to euthanize that horse unfortunately. And it had severe septic, digital sheath. And you can see this is the wound, and this, this is obviously the hoof, you've got your fatlock joint, and this is the wound that went straight into the digital sheath.
And this is a nice, picture because it shows you an unfortunately, a nice outline of where that digital sheath, actually is on the leg. So like I said, metacarpus. 1st, 2nd phalans.
So the digital sheath extends from, you know, the pastton area about a third of the way up the metacarpal or metatarsal region on the palm or plantar aspect of the limb. So, you know, if this animal was treated appropriately 7 to 10 days earlier, the prognosis could have been, could have been excellent, but unfortunately the animal did not survive. So key things when you're evaluating lacerations and you're trying to determine is synovial cavity involvement or any other deeper structure, it doesn't, I'm focusing on synovial cavity, but any other deeper structure, you got to know anatomy, and I would tell you a lot of times, we're now an ultrasound services, ultrasounding, a distal limb or even an upper limb, you know, they have the anatomy textbooks open to try and work out, you know, exactly which structures, which structures are involved.
Limb palpation is critical and not only palpating the affected limb, but also palpating the contralateral limb just to compare and what I'm feeling for is, Obviously feeling tendons, ligaments, joints, but often, even early, you know, even shortly after the injury occurs, that you can actually feel, distension or thickening of the synovial cavity. And a lot of times that's the synovium that's, become edematous, and inflamed. And so you can feel a difference to left versus right, and that can give you a clue that maybe a synovial structure is involved.
And then I take some time. I already mentioned, go ahead and clean the limb up, you know, sedate the animal, block the limb after you've evaluated it, but then go ahead and take some time to explore the wound, and that's digitally, or you can use a probe. And what I'm, I'm looking for there is to feel their bone involvement.
Can I feel cartilage? Can I slide a probe up or down, suggesting, say the digital sheets involved, I cannot feel any tendons or ligaments that may have been even partially transected. Just keep in mind if you're palpating in the past in the palmma or plantar Pasin area, and there is even a small defect in the deep digital flexor tendon.
Yeah, just by, just by definition, the digital sheath is involved even if you can't, don't feel like you can completely assess the digital, the digital sheath. I always take radiographs, one, we're looking for any sort of bony abnormalities, any sort of non-displaced fracture, which can actually take a few days, you know, up to 10 days to, reveal, to be revealed radiographically. The other thing I'm looking for with radiographs is that any air in the synovial structure.
And a lot of times if you look carefully, you can actually see air pockets, you know, actually within the synovial structure. And so look, look very, very careful. Wait for that, and that can give you some sort of idea of synovial structure involvement.
So radiographs and then ultrasonography, I'm not great at ultrasound, but I can tell you a lot of times we will get our ultrasound service to evaluate any sort of distal limb wounds, a lot of times they can trace the wound, you know, see where it goes, whether it goes to bone, and they can actually see whether it actually enters the synovial structure. So that can be helpful. The, you know, if an emergency comes in a last comes in in the middle of the night, I typically do not, you know, call it our ultrasounds to ultrasound.
Call about whether it's synovial structures involved based on my ultrasound, but what I do do is I do synovial centesis, get a sample from the synovial structure and go ahead and analyse it. One of the first things I look for, I look at the colour and I look at the viscosity. And if you've got a, if you've got a synovial structure that is not a standard, so it's nice and, you know, flat.
Against the underlying bone and cartilages, there's no distention, and it's got nice viscous fluid. It is unlikely, I wouldn't say 100%, but it's unlikely to be involved in the injury. And these are some values that I think most people use, to try and decide, is the synovial structure septic, essentially, is it involved in the laceration.
And then, I, I usually take, I will take a sample for bacterial culture and sensitivity testing. I have to say I am doing that a little less frequently, now because a lot of times, either I'd say about half the time you don't grow anything, and then the other half of the time isn't really representative, especially in the, when it's very acute, so. A wound that's less than 24 hours old, is it going to be really representative of any type of an infection?
And so, you know, I'm doing that less try to save the client, some money. However, if it's a, if it is a septic structure that's been going on for a week, I would definitely get a sample for bacterial culture and sensitivity testing, but the acute ones, I'm not sure how beneficial, it really is. And then a key thing, so I've got my physical exam, I've got my radiographs, you know, depending, maybe I've got my ultrasound, I've got my, the appearance of the synovial fluid, you know, I've measured some, done some analysis, looked at the protein, the cell count, and the percentage of neutrophils.
And then what I'm gonna do is I'm gonna distend the synovial structure with some sterile saline and see if it actually communicates with the wounds to see if I get fluid out and some of the key things I'm looking at with that. When you gotta make sure you are actually in the synovial structure, and not in the subcutaneous tissue. What I am looking for is any, even a little drop of fluid coming out of that wound.
And so, you know, a lot of times we end up, you know, if we're highly suspicious that a synovial structure is involved, we'll anaesthetize them and do this with the animal down, which I think provides for a better a better evaluation. And it's a little bit easier on your back. It's obviously more expensive.
But you want to take the, the limb through a range of motion as you're doing that, just to make sure that, because the tissue planes can shift, from when the animal was injured, to when you're doing your evaluation, and so you wanna make sure you take through a range of motion to line up the tissue planes properly to look for any fluid leaking. From the synovial structure. The other thing that I do is I get a 4x4 and I, and I dab the wound, and then have, if I've got an assistant, have them go ahead and, distend the synovial structure, you know, cause I'm, you know, if it pours out, it's obvious, but sometimes it can be a very small amount leaking out, but there's still communication.
The other thing that we do, we use an extension set, a 30-inch, extension set, which gives you a little bit more latitude when you're, when you're actually, you know, from the needle that's in the joint, to the syringe. To, to, to, you know, so, you know, if the animal moves, it gives you a little bit more flexibility. And then, the final thing is, what you're really looking for with this is you, distend the synovial structure.
If it does not communicate with the wound and you take your finger off the plunger, the, fluid should come back into the syringe. And that's something really important that I'm looking for. So I put all those things together and then decide.
Do I think that synovial structures involved, or not? So just briefly, you know, I've talked a lot about inserting needles into synovial structures, what does that look like, there's plenty of reviews in the literature. One of the things that's important is to know multiple sites.
For, synoviocentesis. And because a lot of times you, if you only know one site, your laceration might be right over the site that you typically use. And that can be problematic because you want, it's really important that you go to a remote site, to insert your needle.
And like I said, there's several reviews, on arthrocentesis or synoviocentesis sites, and it's good, if you have an opportunity, on a horse. It's been euthanized or horses in knee cropsy, go ahead and practise and practise. That's the way you get good at it.
So for example, the crop and joint, this is the type of laceration that might involve a coffin joint, might involve the passing joint, might involve the digital sheath, and so often we check all those, all those structures, you can inject you You can go on midline, about 1 centimetre up from the coronary band, you can go on midline and you just insert the needle straight down and you should get in the coffin joint, or you can go off midline at an angle like this, also perpendicular to the ground, and then there's also a planter approach as well that's shown here. And then what you do, inject, the sterile isotonic fluid. So for a coffin joint, I might use 20 mLs.
You want to make sure the volume is large enough that you're actually going to distend the synovial structure. Go ahead and, and then you take it, like I said, you take the needle off the plunger, see if the fluid comes back, take the limb through a range of. And see if there's any fluid coming from the wound and you can see with this wound it might be difficult to ascertain if there is fluid because you know there's quite a bit of blood and so I make sure the wounds clean and dry and I dab it again with a 4x4 grow sponge, you know, and pull that flat back and really look to see if there's any fluid leaking into the wound.
Similar to the passing joint, once again, there's a dorsal and a palmer or planter approach that's been described in the literature. The other way to get into the passen join is sometimes I'll go on midline and once again have my needle somewhat vertical to the ground and just walk off the distal aspect of the first phalanx into the passing joint. And it's similar procedure, similar to the fat lock.
I think most people are comfortable with multiple approaches to the fat lock joint, but for example, this, this laceration involved the dorsal aspect of the fat lock, and so obviously if you're used to using a dorsal approach, for example, you're not going to be able to use that to the joint, you're going to have to use one of your palmer or planter approaches that have been described. And the cars, I think most people are comfortable with. And then the tossis.
The digital sheet can be challenging and I it can be challenging to assess and I would say most of the time, at least in my experience, if the digital sheath is very, if there's absolutely no distention, absolutely no filling of . The digital sheath, then it's probably not involved in the wound. And when I'm trying to stick a needle into the digital sheath, obviously you're limited to where you can insert a needle based on where the injury is, based on where the laceration is.
So if it's a if it's a a palm planter, past the laceration, you're going to have to insert a needle above the ella joint and vice, if it's an injury like this, you could go immediately above the ella joint or you can go in the palma plantapain region. And usually what I do, just remember the sheath, surrounds envelops the, the deep and superficial flexor tendon, and so when you're inserting a needle, a lot of times what I do is I try and go either in between or run if it's proximal to the fatlock joint or run parallel to those tendons, and then if it's in a passing region, you can either go straight or in or you can go on an angle, just palm or planter to the deep. Flexor tendon.
It can be difficult and like I said, radiography can help you determine if it's in the digital sheath by looking for air specifically in the sheath. Ultrasounds can be helpful. Don't forget your physical exam, and this is an example of contrast radiography.
I do not do a lot of contrast radiography, but once again it's a nice image of showing you exactly where that digital, where that digital sheath is. So it can be somewhat difficult, it can be somewhat difficult to assess, but most of the time if the digital sheets involved in the laceration, there's some sort of swelling of the digital sheet, some sort of effusion, so, you know, it becomes, it becomes. Fairly obvious.
The other thing is, don't forget you can probe the wound if you've got a wound in the passion area concerned about the digital sheath. A lot of times you can insert a probe and it will slide right up right up the digital sheath versus if it's just involved, if it's just in the subcutaneous tissue, it will not. So what do we do at this point we want to lavage it, you can do this standing for sure, or on the general anaesthesia.
The thing that's nice about standing, it's a little bit cheaper, but I really don't think you get as good an evaluation of the limb, and I think you can do a better job with the animal anaesthetized, and that may be. You know, a quick anaesthesia in a recovery stall or in the field, or it may be proper anaesthesia with wound repair, one's a bit cheaper than the other. We've already talked about clipping asepticically repairing, you know, if you're doing it under anaesthesia, there's some sort of draping, it doesn't have to be elaborate.
A lot of times I'll put something, some sort of sterile glove or something over the over the hoop. And so then you want to insert your needle into the synovial structure. I used to use when I was impatient, I used to use a 14 gauge needle which is very large, and the problem is, is if that needle slips out of the synovial structure, you end up with a big hole and you can get extravasation of fluid from the synovial structure and subcutaneous fluid accumulation.
So now I tend to use, often use an 18 gauge needle. This is for lavage. I might replace it with a larger needle, 16 gauge needle, once I've got the lavage started and I've got I've got the synovial structure distended.
I mentioned, we've already talked about culture and sensitivity. A lot of times when it's acute, I don't really bother. I'm doing that, however, if it's more chronic, I definitely do.
And then lavage as much as you can, through the synovial structure. I've done as little as 1 or 2 litres and up to up to 6 litres. And usually what I'm doing while I get the lavage started, aseptically, and then I go ahead and bride my wound, .
While I am lavaging, so I do both at once and it's kind of nice cause the lavage fluid sort of is, you know, bathes the wound and washes the wound as you're removing, taking your time, removing or any sort of contaminated, you know, you know, subcutaneous tissue fascia, anything that's really badly traumatised, that's gonna delay wound healing. Like I said, I spend more time debriding wounds than I actually do closing them. I'm gonna talk a little bit about wound deposition, some different techniques, that can be used.
I would tell you, even with the synovial structures involved, I usually, go ahead and close the wound. The worst case scenario is that the wound's going to be here, so we'll talk a little bit about that towards the end of the lecture. I think.
If you can close the wound, it protects it, it prevents retrograde infection, so infection coming in from the wound into, you know, contamination, I should say, coming in through the wound into the synovial structure or bone if bones involved, and it provides a good, a good bandage to help at least get healing started. Local antimicrobials, if it's a synovi structure, I usually just use intra-articular. I'm going to briefly mention regional limb fusion.
I think some people are still using that. In our hospital, it's quite expensive and it's very time consuming, and I'm not sure if there's any benefit to it versus just intra-articular animicrobials. I'm going to talk briefly about drains.
I don't like to use drains a lot unless I've got a lot of dead space. I'm really concerned about the degree of dead space. Bandage cast, we talk a little bit about casts and splints, but some sort of bandage, especially if the animals anaesthetized, just make sure there's adequate support for recovery, and then we've already talked about non-steroid or anti-inflammatories and and always remember if the animal is not vaccinated for tetanus, you should give them a tetanus a tetanus booster.
So regional limb perfusion, like I said, we used to do it a lot. I think we're doing a little bit less, in our hospital. I hope you noticed based on some literature from our hospital, this tourniquet is inadequate.
You need a thicker tour tourniquet to provide adequate occlusion for the technique to work. And then you just identify any vessel distal to the tourniquet and use a 22, 25 gauge butterfly needle and then go ahead and a lot of times we'll give like a third of the dose of the daily dose of Amicain or gentamicin, and if it's, if it's a distal to the carpets, we'll use 30 mLs if it's, it's higher up, higher up the limb, we'll use 60 mL. And there's been quite a bit of work on regional limb perfusion comparing doses of antimicrobials, comparing volumes.
A lot of time you need to leave the tourniquet on for 30 minutes, you know, that people have compared, you know, how long you need to leave the tourniquet on, you know, how long you need to inject it. There's quite a bit in the literature actually on that topic. So this is just an example of a case that was yelling Thoroughbred gelding, it was owned by a veterinarian sister and she actually noticed that this was had this tiny, you can hardly see it, this tiny, it almost looked like a scrape, but it was a small puncture wound to the cranial aspect of the tibiatasal joint, and this occurred about 24 hours prior to admission.
So on physical exam was largely unremarkable except this was very, very lame. This is another thing that I always pay attention to this animal had quite a bit of periarticular edoema and cellulitis. So not only a lot of times you'll have joint effusion, you'll have edoema and inflammation of the synovium which can be palpated, palpate similar to synovial structure effusion, but if there is an infection, often you'll have that peri-articular edoema and cellulitis.
We went ahead and got a sample. Clearly based on this, it was, septic, there was yellow cloudy fluid, it had more viscosity, and like I said to me, I pay a lot of attention to that viscosity because normal joints, it's very viscous, versus a joint that's septic or involved in a laceration, and it loses the viscosity, and it had almost 100,000. White cells per microliter and a total protein of 55 grammes per litre of 5.5 grammes per deciliter.
So this, we didn't look at the percentage neutrophils. I mean, this was clearly an infected joint. Fibrinogen was also high, which is actually a little surprising considering this really was supposedly only 24 hours duration.
So, this was done on an outpatient. Basis, as I mentioned, her brother was a veterinarian and was out of town, so he was gonna take care of this animal once he returned. We did a standing lavage.
A lot of times I really don't like doing standing lavages on tustacrural or tibia tassel joints, because, I worry about the pockets, but this lavage went very well. We were able to lavage 3 litres of fluids through we treated the joint intra-articularly with amihesin, and then also did a regional limb profusion, and then the animal was discharged with an intravenous catheter in place on penicillin, gentamicin. And like I said, I'm fairly conservative with my non-steroidal anti-inflammatory drugs, so I was kept on that for 2 to 3 days.
I did get follow up on this case, and it still was quite a few, . The joint was still quite a fused, but the the the fusion was better, the swelling resolved, and the horse was not lame, and the horse actually did quite well. So even though this injury was at least 24 hours old, it was still acute enough that we were able to, you know, to get the infection resolved with lavage and antimicrobials, and the animal did fine.
So I'd like to talk some a little bit about basic wound management. And as Of getting wounds to heal. It can definitely be challenging.
The whole system of the trauma can be quite severe. And so, you know, actually being able to put it back together and do everything you can, to get, I usually aim for a primary closure. It is ideal.
So primary closure is just basically the incurs and you close the wounds. Delayed primary closure is when you usually more heavily contaminated wounds, but you delay closure for 48, 72 hours while you get that wound debrided and clean and then you go ahead and close it. So that that delayed primary closure is when you close it prior to granulation tissue formation.
Secondary closure, so you're still closing the wound, but you do it after granulation tissue has begun to form. And so these are really wounds with heavy contamination, a lot of tissue damage that you're going to take a couple of days to debride the wound, . And, and get the, get any sort of necrotic tissue, any contamination wound before you go ahead and close it.
And then second tension healing is when you leave it open, and just, you know, allow the wound to heal by epithelialization and contraction. In horses, a lot of times it's fibre into contraction and obviously this can be challenging in the distal limb, and I've got a couple of case examples I'll show you at the end to demonstrate this. So most of the time, I would say in equal equine wounds, we are aiming for primary closure.
And so this is what this might look like, this is this laceration. It's, I, I describe it as a partial degloving, obviously it's not a complete deglobing, but it's a pretty extensive laceration, obviously there's a lot of dead space, and this is how I close a lot of my wounds. There's obviously several different ways to go about this.
But usually what I do, and I'm going to just kind of hit the key points, I put some very, very large vertical mattress sutures using, you know, some sort of 2 polypropylene, 2 nylon. If it's an animal that's going to be well, actually you need to remove these sutures. A lot of times if it's an animal that's gonna be really difficult to remove the sutures, then I might do some sort of absorbable suture, but usually I do non-absorbable monofilament sutures.
So this is, this is, number 2 proline. It's, I use vertical mattress sutures and I place these stents. So basically these stents, there's several different things you can use.
It's basically a 30-inch extension set that's just cut up into little pieces. And usually what I do, if I can, I set these very large sues back. From the wound.
It's not a great example in this case here, but I set them back from the back from the wound. And so they're your tension relieving sutures. Some people also use near far, far sutures.
The reason I like vertical battress better than near far far near is you can use the stents, which take a little bit of a little bit of tension off the switches, they distribute the load over a greater surface area in the wound, and the other thing is some of you near far far near suture sometimes they can cause the skin edges to invert versus your vertical mattress tends to have it, if anything, event a little bit, which I think can facilitate healing. A lot of times what I do, not necessarily in this case, is I've got these very, very large suture set back from the wound and then a lot of times what I'll do is I will use either interrupteds or actually my favourite is, is vertical mattress again, and you can either even split the thickness, so do a split thickness vertical mattress where you split the thickness of the skin at the, at the cut edge to get really nice position and so I will do those along the skin edge as well. You notice with this, .
You know, there's several options for drainage. You could place a drain in this when this would be a good wound. The other thing that I did, and I do with these lacerations is actually penetrate the skin.
That does two things. One, it provides drainage, and two, it takes some tension off that wound edge so you can actually pull it across, and get the, get the wound edges together under less tension. So I mentioned drains.
Like I said, I don't use drains a lot. I always worry about, you know, retrograde infection, coming in from the drain and it's a foreign body. However, if you've got extensive dead space, sometimes you don't have a choice.
If I'm going to use a drain in most wounds, I would use a Penrose type drain. The key thing, if this is your wound. You do not want to have the drain directly under, directly under your wound.
You want to have it off to the side, because for that wound to heal, it's going to need to have nutrients from that subcutaneous tissue and it's got a drain under there, it's not going to heal as well. So set the set the drain off from your suture line. I was always taught, I know some people do it differently, to have no stab incision at the most, proximal or less dependent part of, the drain insertion site.
I just, blindly suture it there. If when you're suturing your drain in place, the key thing is use different suture material to the suture material you've used to close your wound or do something to distinguish it because at some point, in a couple of days in 24 to 72 hours, you're going to remove that drain and you want to make sure you're cutting the right sutures. So either different suture material, different coloured suture material, leave the, leave the tags of the suture material really long, so that you can identify.
And similar, the. Secured in place distally at the dependent part of the wound as well, and once again, make sure that you have you have sutures that are distinguished from the other sutures so you're cutting the right thing. And so if this is my wound, for example, this is my dead space, I'll blindly suture the wound proximal and then have the brain exit at the most dependent part of your dead space so it can drain adequately.
So just moving on, so that's drains, just moving on to special considerations. These are just some other type of, these are just some other type of injuries that we see. This is a case that I had as a resident.
This horse had a puncture wound, it was a roofing nail, so the nail was Only about 1 inch long, it was at the apex of the frog. We thought, obviously that one of the main concerns anytime there's a puncture wound to the hoof, you worry about the navicular bursa, this is the navicular bone, this is the coffin joint, this is the distal phalanx, second phalanx. Or middle phalanx, this is your navicular bursa here.
So anytime you have a puncture when you're worried about this, this, this wing was nowhere near the navicular versa, the horse end up with persistent lameness, radiographs can be normal. And you can see here this horse ended up with severe septic osteo osteitis osteomyelitis of the distal phalanx and was obviously euthanized. And so for me, this is a reminder anytime, you know, it took us a long time to diagnose this because the radiographs, this is the first one more take home message.
Radiographs are not sensitive for picking up lysis, especially early on, it can take, you know, several weeks, and in this case it was over a month to identify any lysis, and then that these nails can actually cause septic osteitis, osteomyelitis of the of the distal phalanx. It did, the other thing about this case, eventually we were able to diagnose it because it did, that osteomyelitis did lead eventually lead to, septic, cough and joint arthritis. This is the more classic one, when you've got this is the frog here, you can you can tell the middle third when they get a puncture to the middle third of the frog, so that's the apex, and this is the base of the frog, that it pretty much goes directly to the navicular bursa, and this is a horse with a septic.
Navicular bursitis, right here, navicular bone, septic navicular bursitis, you can use contrast radiography. I don't use it a lot, but this is a type of case that actually can be helpful because it can be difficult to diagnose these. This one obviously has a lytic lesion.
Audits of vicular rose I'd say in the acute phase, we really don't see that very often, but it's worth taking radiographs. I mentioned contrast radiography can be really useful in these cases. It used to be that traditionally you do a street nail procedure and some people might still do that.
However, more recently, people have been doing arthroscopy or I should say burstoscopy, which, and the results that we've had in our hospital and also the results that were reported in the study from Several years ago were really excellent. And so if you've got a horse with a puncture wound, anytime you got a puncture wound to the sole of the foot, I think it's important to get it thoroughly evaluated and if the owner can afford it, doing some sort of burstoscopy early on can not only save the horse's life, but can also allow it to continue to be an athlete. Briefly, flexor tendon, flexor tendon lacerations, we definitely see these, if it's, if it's just, what I would call a nick or, you know, the tendons just minimally involved, a lot of times these just need a splint, maybe a cast.
They don't need, you know, they don't need repair. When it's completely transected, there's some surgical techniques, . You know, to repair them.
Remember, these are flexitinon lacerations, your extensive tendon lacerations, they do really well with conservative management, so these are the tendons that run down the front of the limb. A lot of times the horses will knuckle initially, however, You know, with splinting, they tend to do really well because it usually just heals and it's not a problem. Versus the flexor tendons, that's a weight-bearing tendon, they need that tendon intact to be able to weight bear, and so if it's more than 50% involved, they probably should be repaired.
We already talked about these types of declotting wounds. This is one that's obviously a lot more extensive and in this case, I would definitely be concerned about the viability of definitely the skin, but just the viability of the distal limb. In these cases, and on an emergency basis, I think one of the important things, and that I was always taught a lot of people don't do this is, the early phase of wound healing, the skin retracts back, and so if you've got a Really extensive laceration, especially on the distal limb and you're a primary care veterinarian, consider attacking that skin together to try and prevent it retracting back, you know, prior to the animal being able to be referred to a referral centre.
Some of these large lacerations, these look terrible, but they can heal. I mean, obviously you want to assess the abdominal thoracic cavities, go ahead and block it, and then just suture it. And this is something that, you know, so long as the abdominal cavity is not affected, you know, so long as there's not any major haemorrhage, this is something that you can definitely divide and suture in practise and This is what one might look like.
This is not the horse that I've just shown you, but this is one that a large laceration, I think the horse ran past, you know, a door that wasn't properly opened or a fence that wasn't completely opened, and you know it's an extensive laceration that we put a lot of drains in and we sued it up and you can put an abdominal bandage on these you know, to provide some pressure as well to help with dead space as well. So the other type of lacerations lacerations of the axilla that often look like this, these can also look extremely bad, but eventually they can do very well. Considerations with these types of injuries, you want to assess the thoracic cavity penetration, pneumo.
Pneumoed sternum, any rib fractures, any sort of foreign body that may have entered into the thoracic cavity that may end up forming a pleural ammonia, an abscess. I had one horse several years ago, it wasn't this horse in this picture that actually had a penetrating wound to its thorax had punctured its heart, and so obviously that didn't go well. So, acute blood loss, jugular vein laceration, esophageal or tracheal penetration, obviously wound infection, and then I'm going to talk a little bit about subcu emphysema that can be quite extensive in these wounds, and sub-cu emphysema can lead to cellulitis, thrombophlebitis, and it can also lead to pneumothorax and pneumo mediastinum if it's not managed carefully.
So how do you rule out these things, the key thing is physical exam. So this horse that I just showed you the picture of before, it was quiet, but it was very alert and responsive. Heart rate, it was a little bit high, but it wasn't too bad.
There was no arrhythmias, no murmurs, so I was pretty sure this animal was fairly stable. The other thing is the respiratory rate was 12 breaths per minute, so it was completely normal, and it had a normal respiratory pattern. It did have a little bit of an increase in the rectal temperature, but its oral mucous membranes were pink and moist, and its capillary refill time was less than 2 seconds, and this animal had good gut cells as well.
So based on my initial assessment of this animal in the emergency. Comfortable, that it probably didn't have a pneumothorax, that it probably, it probably didn't have significant haemorrhage, etc. And then this was, this was a lab work.
So it potentially a little bit dehydrated. You know, its protein was a little bit low, and, this is important as well. It had a little bit.
Creatinine was slightly increased, although it was a poor horse. They tend to run a bit higher, but I'd want to keep an eye on that creatinine concentration, for, you know, if I'm going to administer an amino glycoside, and also any non-steroid or any inflammatory drugs, so I don't give the horse acute kidney injury. So what we did, we placed an IV catheter, we did give this horse IV crystalloid fluids, we did start it on procaine penicillin and gentamicin.
A lot of times I use potassium penicillin if I've got a catheter in, however, if I'm trying to save some money, I will use procaine penicillin, just be very, very careful to make that. Sure that that does not go in the vein. I did start this animal on enbuzone for analgesia.
Once again, if you're using gentamicin enbutazone, always be careful, you know, don't forget the kidneys. And then we lavage the rider patched the wound and put the animal in a stall. So this animal did develop subcutaneous emphysema quite extensively, and it did develop a pneumo media stinum, but you know, it wasn't problematic for this case.
He also had some cranium medialspinal haemorrhage, which we did, we were able to diagnose that on, we were able to diagnose that on ultrasound examination, and other than any microbials, it did not end up being problematic, and he did have azotemia, so we had to stop giving him his gentamicin and phenobuasone, and I had this case a long time ago, several years ago. So, and I will tell you I've gotten, become a lot more careful with my gentamicin and NSAID use even in animals with a slightly high, even with animals with slightly high creatinine or you know, I'm concerned about any sort of blood loss because I have had several animals end up with significant acute kidney injury, . From aminogly probably mostly aminoglycoside but also NSAIDU, so be careful.
I mentioned this animal develops its significant subcutaneous emphysema and this is not uncommon for these axilla wounds. They end up with, they can be all the way, you know, to the gluteals all along their thorax and abdomen, very extensive subcutaneous emphysema, so that's why it's really important that you pack it, you know, if you can cover it with some sort of adhesive, plastic drape, that would be great, and definitely keep them confined to a stall because the more they move, the more subcutaneous emphysema they're going to it just becomes the wound becomes a one-way valve and a sucking sucking type wound. This was healed great.
He ended up doing really well. Long term and has been used, he has a little bit of gait deficit, but he has been used for Western pleasure. So just briefly, in the interest of time, chronic wounds, I do not deal with a lot of chronic wounds.
Like I said, I'm an emergency clinician, I primarily deal with the acute wounds, but some of the things that's in the literature, cost application, I'm going to show you a case in the end where we are. A cost and eventually it did really well. Manuka honey, or medical grade honey, it doesn't have to be manuka honey.
There's been a little bit in the literature on that calcium alginate activated proteins, I don't have a lot of experience with. I do have some experience with the medical grade honey. Negative pressure wound therapy, if the animal will tolerate it and if you can actually get a good seal of the wound, it's something else to consider, and then if it's really chronic and you can't get it to heal, some sort of pinch or punch grafts are things to be considered.
So like I said, I've got some experience with using manuka honey, sorry, medical grade honey, not necessarily manuka honey, we're actually involved in a study of prevention of infection following celiotomy, following a celiotomy incision, evaluating medical grade honey. This study did look at manuka honey, and these are the wounds that were the controls at the top of this graph, and these were the wounds that were. With honey, and you can see the healing time was considering, considerably shorter compared to the controls.
And this is an animal we actually had in the hospital recently, that had, it had a wound over its butt lock. This was a she was a young Billy, and she was not well behaved and would not stay quiet in her stall, and so the wound was repaired. She was discharged from the hospital.
And then she came back in and the wound had completely, completely dehissed. And I think we first saw her at the beginning of October, and you can see this, and we treated all we treated it with this honey, topical, medical grade honey. We did not treat it with any microbials, we did not treat it with NSAIDs, and, and this is just the healing progression and the wound is healing, it's taking a long time.
She's not the best patient, but we, we applied medical grade honey to try and at least get that healing on, on its way. Like I said, it's not just manuka honey, there's different types of honey. This paper, I found, actually showed that Scottish heather honey, was actually the most antibacterial and was the best.
They did warn people that do not use non-sterile honey, you should use a sterile product. And I mentioned this paper here out of the University of Coret, Dr. Kilmers, the senior author, is looked at it honey and wounds and that their results suggested that the medical grade honey did improve wound healing and prevent infection.
So I'm just gonna finish up with a case I had. This was a this was a Philly, I believe she was a healing. We went ahead and repaired the wounds like I described with some large, stent sutures and then some skin edge sutures, .
It de hissed, unfortunately, and then what we did is we put her in a cast. She tolerated the cast very well, which is obviously an important factor to have when you're managing these animals. This is when the wound came out of the cast, we could probably have left it in the cast a little bit longer, but the thing that you can do with casts.
If you can bivalve the cast and use it as a as a splint as well, especially if you do a bandage cast to start with and so this is the wound and it progressed to heal. I was able to follow up with the honour at 6 weeks. The wound was very, very small and the filly was actually doing quite well, and this is her, and, and the wound was obviously, obviously into the joint.
So she was actually feeling very, very good. So, I think the take home message of this case and and this wound from the start was in the joint, the felt love joint was wide open, but they brought it in right away. We were able to anaesthetize the animal to bride the wound.
We got a good lavage on the joint, even though Wound dehest, we were able to keep it clean. You know, I think casting really, really helped get this wound on its way, on its way to healing, and then, you know, a couple of months later, the wound's not completely healed, but the feeling is sound and, you know, getting ready to start training. So with that, I'd like to say thank you for the opportunity and my email address is in my notes and if you've got any questions, I would be happy to answer them via email.
Thank you.