Podcast: Surgical Decision-Making in Veterinary Patients with Dr. Hayes

Galina M. Hayes, BVSc, DVSc, PhD, DACVECC, DACVS, Cornell University

VideoAudioApril 2024Listen
Print/View PDF


In this episode, host Alyssa Watson, DVM, is joined by Galina Hayes, BVSc, DVSc, PhD, DACVECC, DACVS, to talk about her recent Clinician’s Brief article, “Quiz: Surgical Decision-Making in Veterinary Patients.” Dr. Hayes guides us through four challenging surgical cases—highlighting hemorrhage, wound management, respiratory emergencies, and mass excisions. Don’t miss her expert advice!


Episode Transcript

This podcast recording represents the opinions of Dr. Watson and Dr. Hayes. Content, including the transcript, is presented for discussion purposes and should not be taken as medical advice. No guarantee is given regarding the accuracy of any statements or opinions made on the podcast. The transcript which was prepared with the assistance of artificial intelligence is provided as a service to our audience.

Dr. Watson [00:00:10] Hi, everyone. Thanks for joining us for another episode of Clinician's Brief: The Podcast, where we give you a backstage pass to the conversations behind all of your favorite Clinician's Brief content. I'm your host, Dr. Alyssa Watson. And today we are going to be talking about surgical decision-making in veterinary patients. I am so excited for this conversation. It is based on an article that was a case-based quiz. And the quiz questions were a little difficult for me, and so I'm excited to be talking about them. It was a fun quiz to take. And joining me for the conversation the author of this quiz, Dr. Galina Hayes, is an associate professor of small animal soft-tissue surgery at Cornell University. She's going to talk to us about these cases, and some of them are emergency cases. Some of them are elective scenarios and give us some insights on how to get the best outcomes for our surgical patients. So thank you so much for taking the time to sit down with us and talk with us, Dr. Hayes. Before we jump into these cases, if you could just introduce yourself to the audience and tell us a little bit about your background, we would really appreciate it.

Dr. Hayes [00:01:18] Yeah for sure. So firstly, thank you so much for inviting me. It's wonderful to be here and, and have the opportunity to talk about my favorite subject in the world, which is, of course, surgery. But, yeah, I graduated in 1998 from the University of Bristol. Worked in mixed practice for a year in Carmarthenshire in Wales. Then small animal practice, then did an internship, then ER practice for a while. So over the, over the years, I've certainly seen my fair share of emergency surgical presentations. But, eventually I pursued advanced training both in emergency and critical care with Dr. Carol Matthews up at the University of Guelph, and her team and, and then a surgical residency. So now I'm, blessed to be boarded in, in both specialties. And I spend my time at Cornell University in upstate New York, trying to hopefully train the next generation of veterinarians in how to manage their surgical cases. So, yeah, that's me in a nutshell.

Dr. Watson [00:02:29] I think it's wonderful. And I think it's great for your students that you kind of bring that wealth of in-the-trenches knowledge that you had before, you know, you went on to pursue those residencies. So let's talk about these cases. There's four cases that we're going to talk about today. And the first one is the case of a young dog, a young labrador, I believe that, or this might not have been the labrador that might be the next case, but a young dog.

Dr. Hayes [00:02:55] Rottweiler, I think.

Dr. Watson [00:02:56] Yeah, yeah. A young dog that actually presented in hemorrhagic shock after a gunshot wound. So when you have an animal in shock, what are the immediate priorities that we need to think about managing? And can you talk a little bit about how we can distinguish arterial bleeding?

Dr. Hayes [00:03:18] Yeah. Of course. So, hemorrhagic shock typically it's going to present with the classic characteristics of hypovolemic shock. So tachycardia, pale mucous membranes, often a kind of very sharp water hammer type quality pulse in the early phases. And that those clinical features really represent the body's physiologic response to dealing with that depleted effective circulating volume. So you get this strong catecholamine drive, an adrenal activation, catecholamines surge, vasoconstriction, tachycardia, really just trying to maintain perfusion to heart and lungs. Heart, lungs, and brain. Now that something to bear in mind is that if you continue to bleed and your effective circulating volume continues to deplete, then eventually you reach the limits of compensation and that tachycardia reverts back to a normocardia and ultimately to a bradycardia. And typically that ticking down of the heart rate is a signal preceding arrest. And so if you see a patient that looks very shocky but is normocardic, then that should really alert you to, okay, I could be at the decompensated end of this process. Now, how do you differentiate arterial bleeding from capillary bleeding or venous bleeding? Because the arterial system is under higher pressure, the escalation of shock tends to be much faster. The volume loss is much faster. And so similarly, clinical decision making needs to be fast. And our interventions, quite aggressive. And if they're bleeding externally, then typically you're going to see pulsatile bleeding of bright red blood, and a lot of blood volume. Yeah. And those are your sort of big triggers to, oh my God, there's an artery down at the bottom of that wound. We need to jump on that guy right away.

Dr. Watson [00:05:36] Yeah, and that, I guess, is the thing you really want to focus on, too, is that if you see that pulsatile bleeding, you want to stop that right away before you try to, you know, get your IV in and fluid resuscitate and all these things that are really important when we have an animal in shock. But the first step is, if you can stop that bleeding, stop that bleeding. Right.

Dr. Hayes [00:05:59] Yeah, just because arterial bleeding can be so rapid. And so even in the time that it could take you to place an IV catheter, or do you sort of basic assessment tests, that's, you know, blood loss that you can't get back. So if you can get a pressure wrap on there or get a clamp in there, get a tourniquet on, then trying to hold that for the blood loss is is critical.

Dr. Watson [00:06:26] I want to talk for a second about this concept of lethal triad. Because this is something that I hadn't really if I was taught it 20 years ago, I didn't really remember it very well. So could you just walk through that for our audience as well?

Dr. Hayes [00:06:43] Yeah. For sure. So, yeah. I can't tell you exactly how long this has been around, but it's certainly been a hot topic in the sort of trauma literature for a little while now. And I think it's a, it reflects our increased understanding of some of the maybe more negative physiological events that can occur with trauma and with aggressive fluid resuscitation in trauma. And so the lethal triad is a feedback cycle, consisting of a coagulopathy, a metabolic acidosis, and hypothermia. And if we just kind of work through that a little bit, if you have been bleeding profusely and in a shock state, then hypothermia very quickly will kind of come into the setting as part of that. And all of our coagulation proteins are enzymes. They have a temperature range within which they function effectively. And as soon as you drop below that temperature range, so that would be around 36.5-36, those coagulation proteins stop functioning optimally. And this, of course, isn't something you're going to see on a PT/PTT test, because a PT/PTT test is run at a 37.5 degrees controlled environment. Yeah. So just know that you're hypothermic patient a lot, a lot of times he's not clotting well simply because of the hypothermia. So then they bleed more, and you get a coagulopathy due to the hypothermia, but you also get a coagulopathy due to platelets loss and fibrinogen loss. And if we're resuscitating with crystalloids, we're often diluting out that fibrinogen quite a bit. And our crystalloid load will also often be delivering a lot of chloride. The patient may be producing their own lactate, just as part of being in an anaerobic metabolism shock state. And so they'll have a lactic acidosis and then a chloride load sometimes superimposed on top of that. And metabolic acidosis also inhibits coagulation protein function. So you start to see this sort of round and round spiral of hypothermia, worsening coagulopathy, resuscitation, metabolic acidosis, worsening coagulopathy, and it's called the lethal triad because if you start to spiral down and all of those things worsen and worsen and worsen, and then, unfortunately, your mortality risk increases reflecting all of that. And so with that sort of improvement in knowledge, there's been a little bit more of a focus and shift in the paradigm to aggressive early warming of shock trauma patients, switching to resuscitation with blood products rather than going really super high volume crystalloid. And for me, I really start to worry about the crystalloid coagulopathy once you're getting above sort of 60 mil, 80 mil per kilo, total dose. So, whole blood resuscitation, and then watching that metabolic acidosis and just being aware that that may be compounding your coagulopathy and kind of not always as helpful as you might hope it would be. So, yeah, that's the lethal triad in a, in a nutshell.

Dr. Watson [00:10:25] Well, it's really important to know about. And the other thing that really struck me about it, you know, as a general practitioner, if I have a trauma patient come in, I don't have blood products available for me, you know, right there. I'd have to refer that out to our local specialty center. But I have a warmer, you know, and that we use all the time in surgery. And it never occurred to me that doing something, you know, as quick and ineffective or inexpensive as putting, you know, a bear hugger on might actually help, you know, decrease the morbidity, morbidity there. So that's really neat. Let's talk a second about when these animals come in and they're just so critically ill, they sometimes they don't even need sedation, you know, for this initial stabilization because they are so, so sick. How do we, you know, how do I, as a clinician, determine when I need sedation with my shock patient? And how do I balance that with, you know, the urgency of treatment?

Dr. Hayes [00:11:28] Yeah. No, that's a great question. And so, I think at least for me, typically I rely on the patient to tell me if they are obtunded, poorly responsive, laterally recumbent, then that's a patient that's clearly not well compensated. Sometimes trauma, sometimes sepsis. And there I would be maybe a little cautious with sedation type and dose, and think quite carefully about what's needed there. Whereas, you know, if it's your two-year-old pitty mixed with a face full of porcupine quills that you can't even do a physical on because they're bouncing up and down so hard, then obviously you need sedation to, to get in there. But, for this patient that was, had arterial bleeding. They had clamps on that before any kind of sedation was administered or an IV access was, was obtained. And that was simply because the dog was already in decompensated shock that you were able to intervene and do that, without needing said sedation on board. Similarly, if you have a tension pneumo present that is severely respiratory with severe respiratory compromise, recumbent, shocky, that's a patient that you're probably going to put a chest tube in without sedating or sometimes if you need it in really fast without even administering local anesthetic. And you can always top up with those things later. So if you, after they are resuscitated, if you get the sense that they need adjunctive analgesia or something like that, then that's definitely something, you know, never to withhold. But it's just figuring out what your immediate action needs to be and whether the patient can tolerate it and whether sedating them might put them at increased risk. And certainly for patients in any kind of respiratory or circulatory shock situation being very careful of the alpha-2 agonists, just because they can have some systemic effects that are not always super helpful in that sort of situation.

Dr. Watson [00:13:46] Sure, sure. Then for this particular case, the last thing I want to talk about is how this wound was managed. Because, you know, this was a gunshot wound. It was very contaminated. And so can we talk a little bit about how you make the choice between open wound management and primary closure when you have wounds like this?

Dr. Hayes [00:14:11] Yeah, absolutely. And so I think, I think we all want to see wounds closed. Right, I know, I do, you know. Yeah. And, owners generally do too. And you kind of feel like everything's wrapped up in a nice, neat, tidy package if the wound is together. And I think what we what I still have to remind myself is my limitations in converting a wound quickly into a sterile and healthy environment. Yeah. And a wound that is closed prematurely will often dehisce and a dehisced wound now becomes a very expensive wound because you kind of have to sit back and start all over again with the financial burden inherent in that. And so the, the things that would give me pause in primarily closing a wound are heavy contamination because even if I take all the bits of twig and dirt and road goo out of there, I know if I put that tissue under a microscope, there would still be a lot of heavy debris and bacterial contamination. But I can't control no matter how much debridement and lavage I put through that wound. If it's really heavily contaminated, then you have to give it time and let neutrophils and macrophages push that microscopic debris out. And use your debridement dressings, and really an open wound is the best setting for that decontamination process to complete. Similarly, there are some mechanisms of injury that generate a lot of tissue necrosis where, yeah, I can debride first time around, but that necrosis may be a moving target in the first 24 to 48 hours. And so I'll do my initial debridement. Think things look good. Late tissue death occurs. More necrotic tissue occurs develops now in the wound bed that's been closed. And that then sets the stage for infection and dehiscence. And so injury mechanisms that really commonly kind of go in that direction are crushing bite wounds. And we sure see a lot of those in emergency. But any situation where a bite has occurred, the wounds themselves may not be terribly dramatic, so it may be more a puncture situation than anything else or a little bit of tissue ablation, but the level of crush to the tissue will often cause ongoing devitalization that manifests over a couple of days. So crushing bite wounds, high velocity wounds so, rifle bullets, things like that. Again, you'll get a burden of tissue injury that takes a while to declare. So those probably the biggest ones. So a heavily contaminated wound, crushing wound, a high velocity wound. They are the ones to really take pause and go, okay, maybe we need some open wound management here.

Dr. Watson [00:17:24] So as you say that, it just ticks off in my head. I had kind of early in my career, I had a dog that actually was hit by a train. And so it was high velocity and it had kind of torn a whole flap away from the dog's flank and also rolled, you know, the dog had rolled. And so you're going through these things and I'm just going, yes. It was highly contaminated. Yes. It was high velocity. Yes. I never should have closed this, which is what I did. And I spent, I think, an hour and a half lavaging and closing. And it looked so beautiful. Yeah. And it completely died and opened up again 48 hours later.

Dr. Hayes [00:18:07] Yeah. Some of my most spectacular failures of wound management have been doing exactly what I'm advising you not to do right now. So, yeah, I remember a lab that was hit by a car that had a huge flank flap, open, heavy contamination. And I was so overcome by the beauty of that wound after I finished debriding it that I closed it over a drain. And, yeah, the whole thing fell apart like 48 hours later. Pus everywhere, a complete mess. I never should have closed it. So even as you watch yourself in the moment doing these things, sometimes, you know you shouldn't, right? But it's just trying not to succumb to that temptation.

Dr. Watson [00:18:51] Thank you. I don't feel as bad knowing I'm not the only one.

Dr. Hayes [00:18:54] Yeah, yeah.

Dr. Watson [00:18:58] Let's move on and talk about the second case. All right, so this is a lab, and this is an older lab that came in with clinical signs of airway obstruction. And of course, when I first read this case, I, you know, the history and everything, I thought this was going to be larpar or I guess now they call it geriatric onset laryngeal polyneuropathy.

Dr. Hayes [00:19:23] Polyneuropathy. Yeah, a lot of us still call it larpar.

Dr. Watson [00:19:31] However, this did not end up being that. So what were some key clinical signs and diagnostic finding that in this particular case that led you to pursuing surgery?

Dr. Hayes [00:19:43] Yeah. So yeah, this was a fascinating case. So similarly to you, you know, we all do it. We kind of typecast our patients on presentation. Labrador upper respiratory stridor. There has to be a larpar, right? But fortunately, the very astute referring veterinarian had taken a cervical radiograph which came along with the dog, and, and sure enough on that view, you could see quite clearly an obstruction in that upper tracheal area. Other kind of clues that maybe went along a little bit with that with it, and you can't really relay this in an article, but the quality of the tone of the stridor was a little different. It was a little squeakier than you might expect with a, a classic larpar. And, the dog was showing all those sort of signs of chronic progressive airway obstruction and compensation. So she was quite calm, would stand with the neck extended, you could see him kind of trying to work to keep that airway open. He wouldn't take more than a few steps just because he knew he couldn't really cope with anything that needed a lot more ventilation. So he was really trying to manage his compromises as best as he could. But, yeah, we we took a look at the, the film there saw the kind of mineral density, almost obstruction within the airway seemed to be associated with a tracheal ring. Quite smooth in its outline within the tracheal lumen. And so we knew there that we were dealing with a tracheal mass. And you don't have a huge number of options. It's either going to be between surgical resection or putting some kind of stent in there and hoping that the stent might push the mass out of the way. But for a chondroma they tend to be quite firm. And so they don't always respond to stenting as well as you might hope.

Dr. Watson [00:22:03] And then you said this dog really was in a difficult situation when it came in to you. It could really not take more than a few steps without, you know, not being able to breathe. So you had to do something about that, you know, right away. What factors really influence your choice between are you going to go ahead and attempt standard endotracheal intubation or when you're going to jump into that emergency tracheostomy?

Dr. Hayes [00:22:30] Yeah. And I would say, if I think back over the years, the only time I have done a true emergency tracheostomy was a dog that was brought in in respiratory arrest because of a ball stuck at the back of the throat. And this was working ER, and owners literally rushed into the building. The dog was blue. Not breathing, but still had a heartbeat. We took one look in the mouth, couldn't move the ball, and went straight into a slash cut and straight into the trachea. But the times in which you're required to to do a true emergency trach are probably limited to that presentation, i.e. respiratory arrest, heartbeat still present, airway obstruction that you can immediately bypass with an endotracheal tube. Most other times, it's a situation where you have a patient that's been managing their upper airway obstruction for a while, and now you're contemplating anesthetizing them, and you don't know how easy your endotracheal intubation is going to be as you go to intubate as they go under anesthesia. And most times there, we'll have an emergency trach kit kind of available to us. But we're aiming for a standard endotracheal intubation, maybe with a smaller size tube, if we can possibly get it. Now, if you've induced, you've tried 3, 4, 5 times, you've tried with a stilet, you've tried with a small tube, you still can't get in there, the s are ticking down. Then sure, you jump to an emergency trach at that point. But the time we have to do that is is pretty rare. Yeah. So for most, most of the time for us, the need for a temporary tracheostomy is at the end of a procedure when you're trying to recover them. The airways swollen, they're not extubating well and then we'll put a temporary trach in, but it's more of an elective temporary trach, meaning that there's an endotracheal tube already in place. Their airway is maintained. You can kind of take your time. And do a more careful and sort of focused approach.

Dr. Watson [00:24:53] Sure.

Dr. Hayes [00:24:54] I don't know if that answers your question.

Dr. Watson [00:24:56] No, it did. It absolutely did. And then, you know, in this case or in other cases where you actually have to do surgery on the trachea, how, you know, what are kind of the the things we need to think about, the difficulties that we need to manage when we need to have them on inhalant anesthesia but we need access to this area of the body?

Dr. Hayes [00:25:21] Yeah. No, that's a great question. So for me, at least, it breaks down to is the procedure that I'm contemplating something that I can work around an endotracheal tube, or is it going to have the endotracheal tube in the middle of my field? Is that going to really prevent me being able to do what I need to do? And if the answer to that is yes, then I'll start thinking about how to bypass that. When you, there's a couple of other priorities you kind of have to think about. Number one is limiting exposure of the surgeon and the surgical team to inhalant gases. So it doesn't really help anybody if I'm getting a face full of isoflurane for 60 minutes because I probably am not going to perform my best. And, but the patient needs a cuffed airway in place so that if they become apneic or need positive pressure ventilation, they're able to get that. And so, just switching them to injectable anesthesia often isn't really the answer because if you can't maintain a positive pressure airway, then that could be dangerous for the patient at some point. And you also want to prevent any blood or secretions kind of ending up going down that trachea during the procedure. So for this guy, we just, we did an initial endotracheal intubation, put the patient on his back, and then placed a temporary trach tube with a cuffed tube, caudal to where I knew my surgical site was going to need to be. And that kept anesthesia happy, they had their whole little closed system, they could use inhalants, fake a positive pressure ventilate, the cuff on the tube prevented any blood going down there. And it kept me happy because now I had no endotracheal tube in my field. Yeah. And so most times you can achieve something like that. If it's caudal cervical trachea that you're working on, you might have to actually open the chest to get an endotracheal tube in below that. So it just depends how far downstream you are.

Dr. Watson [00:27:34] And then with that temporary tracheostomy tube, what factors are going to dictate how long I leave that in place? Are you taking those out immediately postoperatively or leaving them in for a little while?

Dr. Hayes [00:27:48] Yeah. So for this case, we actually took it out immediately, mostly because we considered after that mass was out of there and the tracheal anastomosis was complete, he had a great lumen. There was no reason to believe that there would be ongoing bleeding or major swelling. He's a lab, so they've got a big trachea, kind of like a big tunnel anyway. So you've got plenty of real estate to work with. The situations I'm leaving a temporary trach in with are more the English bulldog that has had a big palate resection that presented may be in some kind of hypothermic crisis with a lot of laryngeal swelling. And now you're waiting for that swelling to go down, and you want to manage their airway safely through the postoperative period. And typically, there we will keep it in for 24, 48 hours. And with the patient awake and off all sort of anesthetics and sedatives, you can test very easily whether they can maintain their own airway simply by either occluding the temporary trach tube or just taking it out and putting a light wrap over the site. You stand and watch, walk them up and down the room, make sure that they're coping well with that. And if they're not, most of these guys will let you just take your t stay sutures and pop that temporary trach back in again without needing any propofol or sedation or anything like that. They seem to tolerate that standard exchange of a trach tube very, very well. And so that kind of gives you the bandwidth to assess whether they still need it in a very physiologically appropriate situation.

Dr. Watson [00:29:33] Absolutely. I'm not too surprised that they they let you do that. I'm sure we've all had that situation where we've recovered some of those brachycephalics that just sit there with their tube in for like an hour.

Dr. Hayes [00:29:46] They like it.

Dr. Watson [00:29:47] They're like we're good.

Dr. Hayes [00:29:49] Please let me take it home. Poor guys.

Dr. Watson [00:30:06] Veterinary medicine would be a whole lot easier if we had all the time we wanted to work up cases. But sick patients, impatient clients, and stacked schedules mean we're usually feeling pretty pinched. Meet your new best friend, the revolutionary new Plumb's Pro, a powerful, all-in-one clinical companion designed to help you tackle your toughest cases with confidence. Plumb's Pro combines concise and practical content to guide your work up with a library of pet owner resources and, of course, accurate, continually updated drug information. You'll find all you need without cluttered search results or a pile of dusty textbooks plumbs.com.

Dr. Watson [00:30:23] So we're going to talk about another case. Okay. Let's switch gears. And we're going to talk about a case of a of a nonhealing wound. So this dog had a wound that had been surgically closed multiple times and had multiple rounds of antibiotics. Some of them even guided by culture and sensitivity that just then kept opening up. So what is you know, how did that help us getting a diagnosis? What's the significance of repeated closures and reopenings of a wound when understanding the etiology?

Dr. Hayes [00:31:31] Yeah. So I think, as with so many things in surgery, you know, hindsight is 2020, right? And by the time a wound has dehisced and reopened on its third or fourth occasion, you're pretty much getting the sense, you know, that all is not normal at the bottom of this wound. And it's probably not just a standard dehiscence kind of situation. And so, generally, a recurrent dehiscence on a wound is implying that there is something there that the body is not able to cope with. And the two sort of top candidates would either be a chunk of foreign material that's just causing a persistent nidus of infection and inflammation in the wound bed. Or a heavy burden of necrotic tissue. But if you've opened that wound, flushed it out, everything looks great, you've cultured it, recloses and then it dehisces again, then yeah, I'm probably thinking hidden foreign material and some kind of draining tract is top of the list. And, over the years, I mean, I think the the challenging part is the wound can be quite a long way away from the foreign material that it represents. And so, in this particular case, the wound was right down between the toes, but the foreign material was up the back of the antebrachium. And, we had another case recently with a flank wound where the foreign material was right up mid thorax. So, you know, these things can be 12, 14, 16in away from from where the wound is. And, yet not always the easiest thing to locate.

Dr. Watson [00:33:22] Sure. Yeah. We have that situation all the time where we live. We have those grass ons, called foxtail sometimes. And and you can be amazed how far they migrate. You know, classically, I think of them between the toes, but I've seen them, I've even seen them in an animal's bladder where we identified on ultrasound. So that was the next thing I wanted to talk about. There are some really significant differences between the sensitivity of all these imaging modalities when we're talking. And this dog will let everybody in on the secret. This dog did have foreign material. That's why this wound kept opening up. So what are what are some of the key differences between radiography, ultrasonography, CT, and MRI when we're looking to identify foreign bodies?

Dr. Hayes [00:34:13] Yeah. And so, I think that they can all have their place, but the difficulty with radiographs is radiographs are pretty good at identifying metal or bone. Yep. And anything else is just going to fall under the bracket of soft tissue. And it all kind of merges together. And so unless you have a really obvious gas-filled tract, it can be very difficult to identify even quite large chunks of wood or plant material, or anything, anything basically nonmetal on a radiograph. And so although it's not wrong to take them, they're probably going to be lowest sensitivity of your test because at least for me, metal foreign bodies are the easiest to diagnose. We normally know ahead of time that that's something that that might be in there. And most of the things that we end up chasing over a period of time and causing us trouble will be wood or plant material. In terms of next step up, it depends a little bit where it is. So your choice is past plain radiographs are CT or ultrasound. In ultrasound, of course ultrasound waves are obscured by the presence of air or gas. And they also can't reach through bone. So if your foreign material is somewhere in the pelvis then ultrasound probably isn't going to be your best bet because you're not going to be able to penetrate through parts for pelvic bones to image. But if it's somewhere you think out on a limb or in the subcutaneous tissue along the flank, an ultrasound is very, very sensitive for following a tract back from a wound and then finding that little halo of fluid around the grass, or another piece of stick or whatever it is. So as long as it's in a location accessible to ultrasound, ultrasound is probably your most sensitive go to and cheaper than a CT. CT is has a sensitivity down to two three millimeters depending on the slice thickness and the quality of the CT that you're using. And would be our go to if something that's within the thoracic cavity where you've got the gas in the lungs preventing ultrasound penetration, or something deep in the abdomen, something deep within the pelvic canal. And there again, you may not see the foreign material itself, but you may see a contrast enhancing tract reflecting the inflammation associated with the thing that you're after.

Dr. Watson [00:37:01] Sure. So that, that tract, you know, like we said, most commonly, these are going to be foreign material. That's what the body's reacting to. That's why, you know, these wounds keep opening up. But there are some instances where they're not. So when should biopsy and histopath be considered? And can you just briefly tell us a few of the typical characteristics of things like immune-mediated draining tracks?

Dr. Hayes [00:37:28] Yeah. So immune-mediated tracks, you classically there will be multiple. And they will be fairly shallow. Anal furunculosis is a good example. It's rare to see an isolated tract in that disease. There'll be cellulitis in the surrounding tissue. And you may have a breed predisposition situation kind of going on there. And for sure, I think, biopsy can be helpful in that situation. But if it's a solitary tract and the peripheral tissue looks fairly quiet, and you've done your normal due diligence in terms of culture and explore, then probably foreign body is going to be higher on your list. Now, I'll preface that by saying, I've never worked in an area where there's a lot of fungal disease. And certainly there are some fungal infections can cause draining tracts. But, for me at least, that's never been a common enough part of my practice for me to really give you a a solid clinical perspective on that.

Dr. Watson [00:38:43] Let's move on to our last case. The final case is going to be one of a large soft-tissue sarcoma. And this particular tumor had been previously excised. And unfortunately, during that surgery, they had come up with incomplete margins. So can we talk a little bit about what are the challenges when we want to achieve curative excision of these tumors that have we're already on a second or sometimes I've seen them even on a third procedure, you're going back in to try to get all the all these tumor cells.

Dr. Watson [00:39:19] Yeah. So for sure the first cut is going to be your best chance at cure. Because in your first procedure you're dealing with that natural biology situation where the tumor cells pretty much you could hope that they're all going to be in the region where you're palpating the mass. Plus, whatever margin the histology of the tumor type dictates. And you've got that sort of background of research behind you to say, okay, mast cell tumor. I need this lateral margin. This deep plane. Sarcoma, I need this lateral margin in this deep plane. Whereas once you're into a recut situation, it becomes much harder to predict what kind of margin you're going to need. Historically, we will cut on the scar. So you're using the scar of the previous tumor, and then you're taking your lateral margin based on that scar. But if there was a lot of dissection during the procedure or undermining, then that those tumor cells may now be distributed over quite a wide area. And it becomes very hard in your surgical procedure to really predict exactly where your lateral margin now needs to be. Well, sometimes you use CT just to tell us if a deep plane was taken first time around. So on CT scan, you can mark the site of the scar. And then you look at the deep tissues underneath that. And you can generally tell whether a deep fascial plane was taken or not. And then that will allow you to plan for your deep facial margin next time around. But, yeah, if you can get it the first time around then, then that's definitely your best chance at it.

Dr. Watson [00:41:10] Absolutely. Can you talk a little bit about just the term en bloc resection, and what that means, and how that affects your surgical planning?

Dr. Hayes [00:41:20] Yeah. And so, en block literally means in a block. Yeah. And the way I kind of mentally envision it is that the place where the tumor cells live, plus whatever lateral margin I need is a kind of no go zone in the sense that I assume that that entire block of tissue is filled with tumor. And if my instruments enter that block and then come back out again, then I have the risk of contaminating the remaining hopefully healthy, clean tissues with tumor cells. And so therefore, I'm looking at treating that entire block of tissue as a sort of no entry hot zone. And so I'll make my initial skin incision circumferential all the way around. And then you try and achieve a perfectly vertical cut straight down. So you're using scalpel blade most times to do that. Maybe you'll use cutting cautery. If you use scissors, you're keeping them in that vertical plane with no blunt dissection at all, but just making very sharp, defined cuts. Find your deep margin and then come below your deep margin so you never enter that block of contaminated tumor tissue. Just keep the whole thing together as if it's got a little ticking bomb inside there where if you enter it, it goes off. Yep. And, and, yeah, that's, it's it's definitely not technically challenging to do. It's just kind of remembering the mindset, which is quite different to how you might approach say a wound closure or a more standard soft-tissue procedure.

Dr. Watson [00:43:08] Sure, sure. Yes. Where you can, you know, my scissors are going in all different directions as I'm undermining skin and things like that. No, it makes perfect sense.

Dr. Hayes [00:43:17] Yeah. And then once you've got your block out, then change to a new set of instruments. Change your gloves, assume that your instruments might be contaminated, and then you can kind of switch to your okay, now I'm in recon mindset and I can undermine all I want, do whatever I need to do to get this thing closed. But that oncologic path is now out of the way.

Dr. Watson [00:43:38] That's a very good tip too. And we're going to talk a little bit about closure. But before we do, I wanted to talk a little bit about doing something prior to the procedure. Like using radiation or potentially pre-operative chemotherapy to decrease the the tumor size.

Dr. Hayes [00:43:58] Yeah. And, and so I think, I think certainly preoperative radiation can, followed by surgery, can achieve better outcomes. There is a little bit of an increased risk of dehiscence after reconstruction if radiation has been in the mix because, of course, radiation inhibits dividing cells, and therefore will inhibit cell healing. And so, you know, that has to be something that owners are aware of. And the whole team is kind of on board with. And we're going to we're going to exchange better tumor control for potentially more problems with wound management. Yeah. And and as long as everyone's okay with that then then great. Go for it. I would say the situations we really kind of maybe focus on that would be on injection site sarcomas. The, the kind of really nasty tumors where having preoperative radiation is just going to really have a big influence on outcome. If it's a low-grade standard sarcoma, then probably pre-op radiation isn't going to be the make or break. If it's a small tumor where it's easy to get big margins. Then again, radiation may not be worth the additional cost and morbidity depending on what radiation you have access to. Pre-op chemo, probably the one that springs to mind for me is down-staging mast cell tumors with a little bit of prednisone for a few days before surgery. And particularly those big fluctuant angry mast cell tumors where you palpate and you really don't know where to put your margin because you've got red angry tissue everywhere. And it's very, very ill defined. And if you cut them in that state, then firstly your risk of dehiscence is higher. And secondly, you'll probably have a much bigger surgical wound than you truly need. And so we'll hit them with pred even just for 48 hours. And that will often let them come down to something that's much more manageable. And doesn't seem to have any negative effect on your likelihood of achieving a clean margin or risk of recurrence or anything like that. So yeah, that would be probably one of the biggest sort of pre-op chemo situations. If you consider, you know, anti-inflammatory pred as chemo.

Dr. Watson [00:46:30] Yeah. I mean, I definitely do in that situation. And honestly, that's exactly what I was thinking of because I never that is one thing that I struggle with is how long do I give it. And so it's nice to know that even just 48 hours or so of some pred might, might really help increase the success of that surgery. So let's talk about closure, okay. Because this, you know, and particularly in this scenario, there was a very, very large that the mass had recovered. There was a large area that needed to be closed. And they ended up doing that with a flap. So can you talk a little bit about some of these axial pattern flaps, how we make those, and what can we do to increase the success of those flaps?

Dr. Hayes [00:47:17] Yeah for sure. Yeah. So axial pattern flaps are kind of a wonderful tool that's available to us as veterinarians. It's a little unique in that cats and dogs have this anatomy to their skin that allows for an axial pattern flap. Humans do not. So if you ask a human surgeon about how many actual pattern flaps they do, they'll roll their eyes at you and look like you're crazy. But, yeah, for us, it essentially the definition is a area of the skin that is supplied by a specific and anatomically repeatable vessel. And by raising that flap around the zone of perfusion of that vessel and maintaining the vessel at the base of the flap, we can then swing that flap into new locations, close primarily the bed that it was raised from, and use that flap as a means to recruit healthy, perfused skin into a place where we need it. So typically a large wound after a tumor resection or maybe a traumatic wound that's now ready for closure. And there are not too many places in the canine or feline body that are not amenable to flapping. Probably the only exception is distal extremity. So below the elbow, below the hock on the front and hind limbs, can be a little bit more challenging to flap. Although, having said that, I've done some flaps on dachsies that have gone quite low on the leg just because they have short legs relative to how deep their chests are. So. So I can be very handy.

Dr. Hayes [00:49:00] But, a really wonderful resource if you're looking to learn more about flaps is Dr. Pavletic's Small Animal Wound Management And Reconstruction, and he has a whole chapter in there telling you the boundaries of the flaps, how to mark those out based on anatomy, where you might expect to find them, what flaps are useful for what areas of the body. But some general tips if you're raising a flap for the first time, always start from the distal end of the flap, meaning the end that's away from the supplying vessel. Start there. Get some stay sutures in that edge of the flap. And then as you start to raise and undermine the flap, make sure you're undermining deep to the cutaneous trunci or deep to the platysma muscle if you're up in the neck because for blood vessels that you want travel within that muscle or between the muscle and the skin, so do a fairly deep undermine and then start to lift the flap up and put a bright light behind it. So a headlamp or your OR light, and you'll be able to see the blood vessels coursing through that flap, kind of like the branches of a tree. And you're looking for them to coalesce on the main trunk, which is a supplying vessel. And then just put your cut so they're equidistant from that trunk as you follow that the flap down towards the base, towards that supplying vessel. And then don't over dissect the base. Yeah. You don't want to kill your tree by overzealous dissection at the last minute. So, be conservative as you get close into that area. And then when you go to rotate the flap, try and keep a nice gradual curve to the rotation so you don't kink off that vessel as you're bringing the flap around. But you don't need any special equipment to do this. Just a scalpel blade, pair of scissors, and a headlamp. So definitely within the reach of GP's equipment wise. You can certainly, if you want to get comfortable with looking for these vessels and raising the flap, you can see them well on a cadaver. And so if you have the opportunity to, to do that ahead of time, that will give you some confidence about where these things are going to be located. Yeah. So definitely something you can do in a, in a practice setting. They can be time-consuming. Yep. Just not so much in the raising, but suturing them into place. You're often managing quite large wounds, and they just take a little while to get all the tissues opposed nicely.

Dr. Watson [00:51:47] Are there any special considerations monitoring these flaps post-operatively? Or is it just pretty much like any other surgical incision?

Dr. Hayes [00:51:56] Yeah, you're pretty much one and done. I generally don't play for a drain beneath a flap. I will place some anchor sutures between the underside of a flap and the wound that it's going into, just to try and close that dead space. Just make sure you're anchoring sutures stay away from the tree trunk, so to speak, so you don't inadvertently tack your back down. Yeah, yeah. And, and other than that, I don't bandage them. Normally you're doing everything you can to keep that rotated vessel very happy. And so you're trying to avoid any compression, any cold injury. So don't icepack the flap. You want it nice and warm and perfused, and your patient to have nice, good circulation. Maybe don't let them be too super active. So leash exercise only for the first couple of weeks. Try and keep them a little quieter than normal when they're at home. And the flap is going to tell you within two, three days whether it's 100% happy. Sometimes you may see some necrosis of the very end of a flap or a corner here and there. And oftentimes you can just trim that back if it declares. And then just for a few skin staples in just to repair any defect that develops. But it's rare to lose a flap completely. Yeah. Yeah. So, yeah, I generally warn owners about the risk of some flap loss. But let them know it will generally be further ahead than we were when we started. Yeah.

Dr. Watson [00:53:41] Just let nature do its thing.

Dr. Hayes [00:53:43] Let nature do its thing, yeah.

Dr. Watson [00:53:46] All right, well, that was the last case. I really enjoyed this conversation, and it was really fun to learn a little bit more. I got some some pearls from you. Even above and beyond the great information that was in the quiz. So, everybody at home, I encourage you to go take this quiz. It's so fun. And you can see a little bit more about these cases. Before we sign off, there is a little game we play at the end of our episodes. It's a fun little game of would you rather questions, and I would love it if you would play with us.

Dr. Hayes [00:54:19] Oh, sure. How could I refuse?

Dr. Watson [00:54:26] Okay, first question, and one that I ask pretty much almost every surgeon that I have on on the program. Would you rather perform surgery on your own pet, or do you like to have a trusted colleague do it?

Dr. Hayes [00:54:40] Yeah. Well, I would say over the years I've become more and more of a control freak. Is that, you know, I know it's hard to believe that a surgeon needs control. You know, how can that be? But, yeah, it would definitely be me doing surgery on my own pet. Certainly at this stage. Mostly because, you know, if something goes wrong, I don't want to rot, I don't want to have lost my pet and rotted up my relationship with a colleague all on the same day. So, yeah, I'd rather it was my fault than anybody else's.

Dr. Watson [00:55:15] Yeah, that speaks to me because I really feel the same way. A lot of times I choose to do things myself because, like you said, we can't control every outcome. And I don't want one of my colleagues feeling like that was, you know, something that was their fault.

Dr. Hayes [00:55:31] Yeah. I think the only time I'd be reaching out would be if it was something that was right out of my area of expertise. So, you know.

Dr. Watson [00:55:39] Oh, there's definitely things that. Yeah, I am 100% ready to say I can't handle that. I need somebody.

Dr. Hayes [00:55:50] Yeah.

Dr. Watson [00:55:53] Okay. Would you rather start over at a new university every single year? Or never be able to leave the the position that you have right now?

Dr. Hayes [00:56:04] Would the new university be in different countries all in the same country?

Dr. Watson [00:56:09] No. I think you could have them all over the world.

Dr. Hayes [00:56:10] Okay, if they were all over the world, then a different one every year.

Dr. Watson [00:56:14] Okay, excellent. We like new and exciting places to go live.

Dr. Hayes [00:56:18] Yeah, my kids would hate me. And so would my husband. But, yeah, I think that would be. Yeah.

Dr. Watson [00:56:24] I think it would be fun to experience all those things as well. Just there's amazing places out there. I love to travel. So.

Dr. Hayes [00:56:31]Yeah. And I mean, everywhere I've ever worked, I've learned something new. Even when I locum, you know, you. Yeah, you pick up the most amazing tidbits and then life's a journey. Yeah. You got to keep traveling.

Dr. Watson [00:56:45] If you had to choose would you rather have to retrieve an endotracheal tube that had been aspirated or a urinary catheter that fractured off and was stuck in that urethra?

Dr. Hayes [00:57:01] Hmhm. Well, at least where I work right now, it would probably be medicine that would be being sent after the endotracheal tube because they would just pop down there with a scope and some graspers, and we'd be good to go in about five minutes. So by default I would be stuck with the ucath jammed in the urethra. So yeah, I'll take that one.

Dr. Watson [00:57:26] Take that. Yeah. And I think that's great. I'm glad that there are people like you that are willing to go grab that.

Dr. Watson [00:57:34] Okay. If you had to pick one, would you rather practice without electrocautery or without hemoclips?

Dr. Hayes [00:57:48] Well, I love both dearly, so that would be a wrench, but it would have to be without the hemoclips because I use electrocautery on pretty much every procedure I do, whereas the hemoclips, I only use on the really big scary ones. So I'd have to I'd have to go with the electrocautery and then work out how to somehow get the hemoclips back.

Dr. Watson [00:58:17] Okay. Last question. This one's coming because my boys are big, Disney Disney Plus fans. We just finished Percy Jackson and the Olympians.

Dr. Hayes [00:58:30] Oh, yeah.

Dr. Watson [00:58:30] Yeah, it was really good. It was fun. And so, we just finished it. So last question. They in the final episode, I don't want to give it away for everybody, but there was a little cameo by Cerberus the three-headed dog. And so if Cerberus the three-dog came in for surgery, postoperatively would you put an e-collar, like one big giant e-collar on all three heads or would each head get an e-collar?

Dr. Hayes [00:59:00] Definitely three collars.

Dr. Watson [00:59:02] Three collars. I think so too because otherwise I think they'd fight.

Dr. Hayes [00:59:07] Yeah.

Dr. Watson [00:59:12] Okay, that was all my questions. Thank you so much for joining us. I had a wonderful, wonderful time. And thank you.

Dr. Hayes [00:59:19] My pleasure. Thank you so much, everybody. Thanks for listening.

Contact us:

  • Podcast@briefmedia.com

Where to find us:

The Team:

  • Alyssa Watson, DVM - Host

  • Alexis Ussery - Producer & Multimedia Specialist