Good day everybody. Thank you very much for participating in the conference, and I certainly hope to see all of you one day soon, hopefully. Today's topic is going to be on mandibullectomy and maxillectomy in dogs and cats.

The by far the most common, indication for performing mandiblelectomy or maxillectomy is for a tumour in the mouth, that would involve the mandible or the maxilla. So the most common oral malignancies in the dog are oral melanoma, fibrosarcoma, and squamous cell carcinoma. I would just, like to point out that melanoma in the mouth is, almost always.

Malignant, whereas melanoma in on in other other sites in the dog may not be. Malignant. And then in the cat, the two most common are squamous cell carcinoma and fibrosarcoma.

As a matter of fact, you may have heard the little saying, you know, what are the three most common malignancies in the oral cavity of cat, and it's squamous cell carcinoma, squamous cell carcinoma and squamous cell carcinoma. The reason being that it is by far the most common. And fibrosarcoma comes at a distant second.

Whenever we are dealing with a patient that's got a malignancy, we want to stage the patient so that we know where else this tumour might be and, and know if we are going to do the right treatment for this particular patient. So chest radiographs or CT are indicated. And then, lymph node assessment and that can be done with final aspirate.

We know that palpation alone is not accurate to let us know if there can be metastatic disease or not. But final aspirate for the head and neck really limits us to the sub or the mandibular lymph nodes if We are only aspirating the ones that are easily accessible. Of course, you can do ultrasound guided to get the retropharyngeal.

And another way to go about this is to identify the sentinel lymph node, and there are different techniques. The one that we like to use is Indirect CT lymph lymphangiography, and then, you know exactly which lymph node to target with your aspirate or potentially removal. In order to prepare for either of these surgeries, I think that three dimensional imaging of the tumour and the area is incredibly helpful so that you can plan your surgery appropriately.

And know what your margins are going to be. Sometimes what we can see, on the physical oral exam can sometimes underestimate the size of the lesion. So, CT is my preference, .

Not really sure how well MRI would work. I just don't have enough experience. Typically, when we are looking at bones, CT is considered superior and given that obviously mandible and maxilla are bones.

Maybe CT is better, but again, I don't know of any comparative studies. So it will help determine the tumour extent and then for the maxilla, it will also determine if there's any turbate involvement and importantly also if there's any orbit involvement, which would then be a more caudal tumour and may require an orbitectomy as well. Cross-matching or blood tapping, typing, that is, in part, particularly for the big maxectomy, so the hemimaectomy and the caudal maxectomy, would not be wrong for a mandibullectomy either, particularly the caudal mandibullectomies, that would be appropriate.

I think that the risk of having significant blood loss is more so with the maxectomy and particularly the caudal ones, but again, caudalheimadectomy can also have some significant blood loss. So, mendi like to me first. There are different types of mandibullectomy, so there's the rostral unilateral, shown over here, the rostral bilateral, segmental rim, segmental, caudal where it's the ramus, the complete and then complete with contralateral rostral.

So, the textbooks and those diagrams are gonna be very clear in the delineation of one versus the other, but just understand that. Where you make the osteotomy for any of those and the combination, is going to be dependent on the tumour, tumour size, tumour type, location, and therefore, there are many possibilities as to combination of different things and so I don't think that this is the, the only, Locations where osteotomies can be performed, but it can be longer, smaller, again, it all depends on the tumour. But for the purpose of presenting the topic, it's convenient to have it be so clearly defined.

So the mandible anatomy, there's the synthesis rostrually and then as we go caudle, we're gonna, we have the body which has the teeth anchored in the body, then we have the ramus, and then, just to point out the mandibular foramen which will have a nerve, artery and vein, . And then the, the head of the condylar process is going to be the what's going to be the TMJ temp temporomandibular joint. So we're gonna look at the complete mandibullectomy with the idea that this will have us talk about the rustral aspect, the, the body and the, the ramus as well.

And so if you, if you appreciate all of those aspects, then you'll be able to either do a caudal or a rostral hemi, a segmental, . So for the hemiadulectomy, it is nice to do a coyotomy in the cheek area from the commiser so that it allows you to have easier access to the ramus. That is not absolutely necessary.

It's not an absolute necessity. The complete hemiendectomy can be done without doing the incision in the cheek area, but it, in my experience, it's definitely more challenging to do without, to do it without the skin incision. And then we're gonna go around the mandible.

And we're gonna do an osteotomy, the synthesis, and that will allow us to kind of pull them that mandible lateral and give us access to the medial aspect towards the ramus. And so the We're gonna go through the procedure on a cadaver dog, so that we can see a little bit better step by step. So here we have the head of the dog and then the skull just to show again the anatomy.

And then we have the commissure here. The oral cavity will stop behind the last molar, coddle to the last molar. So that the ramus is behind the the mucosa that is in the oral cavity.

So we're gonna start by making our incision into the cheek area. It's gonna be a full thickness. We can palpate with our finger to see what is the caudal extent of the pocket of the cheek.

And then we can we can cut the skin. Cut the sub Q, the muscles, and then cut the mucosa, and then that really provides a better exposure of the caudal aspect of the mandible. And then, we are going to make an incision into the mucosa, of the lip that is reflecting onto the gingiva, and this is just to show the frenulum of the lip that is between the canine and the first incisor.

Nothing special about it, does not change anything that we do. And so, we've made our incision close to the gingiva, but obviously, depending on where the tumour is, we may have to make our incision. Closer to the To the edge of the lip, so margins will decide dictate where that incision is made.

And then we're gonna make an incision also on the medial aspect and if possible, if the, if the margins allow us, it's nice to preserve the salivary duct that is in the frenulum of the tongue. And so this is the opening of the salivary duct. So it's nice to preserve it if you can, if the tumour is such that you need to sacrifice it, no big deal.

And so, we've made the incision, while preserving the opening and the salary duct, and so we are fairly close and again, this will all depend on tumour size, tumour location. And then we're gonna start to elevate ventral to the mandible and eventually, what we will want to do is to have the lateral and the medial side communicate ventrally. And so, this is what we're doing here.

We've created a tunnel, ventral to the mandible, where we have the lateral aspect and the medial aspect communicate where the incisions were made in the mucosa. And then we're going to extend that the entire length of the body of the mandible. Then, we are going to create a we're going to have the, the communication also, between the lateral and the medial aspect so that eventually the, the mandible can be all excised and removed.

And then, and then so we, we have our incision here into the cheek, and we have our incision here that was along the gingiva of the mandible. So this is the mucosa of the cheek and so we can incise through this so that we can have access to the, to the mast muscle and, and then to be able to have access to the ramus. So we are We're gonna cut the mucosa here, that's really the mucosa of the cheek, and it basically connects the incision from what we did originally in the skin and mucosa and then to the incision around the mandible.

So we've, we've done that, and the first osteotomy, before we go and dissect here, we're gonna make our osteotomy in this instance, we're doing it on the synthesis, and then this allows retraction of the mandible laterally and it gives us a very good access to the medial aspect of the mandible. So once we've freed it up from all of the soft tissue, we are able to really pull that mandible laterally. And then as we do so, then we are able to identify The the mandibular foramen with the nerve and there's gonna be the artery in the vein as well, so that we can ligate the vessels and transect them before we cut them and avoid a lot of the bleeding that will occur if you were to cut those before ligating.

So, the, the ability to retract lateral, Provides the ability to identify and address these anatomic structures. So here we're showing the mandibular foramen and in there we have the inferior alveolar artery and the inferior alveolar nerve. So then we're gonna continue, we can elevate the muscles on the ramus.

And then Before we, we start the surgery, we need to have decided where our osteotomy is going to be. And so in this particular instance, this is not a full complete hemimandibulectomy in that we're gonna leave a little bit of the dorsal aspect of the ramus in the head, . And you, you know, if the tumour it is let's say at the caudal aspect of the mandible, you don't necessarily need to remove all of the ramus, and so in this instance, we're making an osteotomy across the ramus.

And then we're gonna free up all of the muscles that are attached to the caudal aspect of the mandible. And then that allows us to remove it. So as you can see, Our osteotomy was it throughoramus dorsal to the TMJ and so we made our osteotomy from the oral cavity, sorry.

Going from cranial to caudal and we were a dorsal to the TMJ so that we had to, and this is where we're dissecting the TMJ as well. And important to note that the TMJ is quite wide from lateral to medial. So we've removed it.

But this is to show that depending on again where the tumour is and what your margins are, you could go ventral to the TMJ so that in this instance, you would not have to Dissect the TMJ. You can go dorsal as we have just shown with the The cadaver example and then you can also go ventral to ventral to dorsal or dorsal to ventral cranial or rostral to the TMJ. And then you can remove the whole thing if you need to.

If you do a completeimandilectomy to where you remove all of the ramus, the zygomatic arch is going to be in the way at about this level, and it is helpful to remove the zygomatic arch to get access to this area, but it, again, this is another thing where it's not an absolute necessity to remove the zygomatic arch to be able to dissect around here. It's, it's doable without, it's just more work and maybe a little bit more frustrating. So now we have the, the mandible that's removed and now we are going to close the area.

Remember that we had made an incision across here, so the edge over here is gonna come to the edge over here. And so we've sutured this back together over here, and then towards the top is gonna be the cheek and towards the bottom is going to be where the mandible was. And so we are going to close the edges of the incised mucosa that was lateral and that was medial to the mandible.

So we have closed the edges over here and then we are going to start closing the cheek area over here. And so you can see that the, the suture line has been over here. For the mandible, I am fine and, and I think it's great to do simple continuous because there's not as much tension.

And if there were to be a dehiscant, you don't have food going into the nasal cavity, which is the case for the maxilla. So for the maxilla, I prefer to do interrupted suture pattern with the idea that if one fails, not everything will come apart. But this is definitely a personal preference, like there are many surgeons that will still do it continuous for closing the maxilla.

So, what is the appearance, cosmetic appearance after this type of surgeries? So here's a total mandibullectomy, no support for the tongue, so the tongue is hanging and something to be prepared for, and, with a total hemimanulectomy, it's, it's really Really difficult for a dog to really be able to try to keep their tongue inside. But in order to help, you can do a chyloplasty to wear.

You actually remove part of the edge of the upper lip and you remove part of the edge of the lower lip, and then you close the upper lip and the lower lip. Together caudily such that you make the commiser more rostral and therefore you provide more support for the tongue. So, that is one thing that can be done to help with not having the tongue hang so much as shown in the previous picture.

Unilateral unilateral rostromandectomy. So here as shown over here, this is what's removed, so we go on the synthesis and we go caudal to the synthesis in this particular example. Most tumours, even though they might be located over here, sometimes it's, it's easier to just go cadal to the synthesis, but it doesn't have to be.

And so same principle as the mandibulectomy that we showed before, incision on the medial aspect and incision on the lateral aspect and then we're gonna make them communicate caudal to the synthesis if that's where the the plan mandectomy is. You can use an osteotome or Power equipment, I think it's easier to do the power equipment and then you remove the mandible and then you're gonna close the the cut edge of the lip to the cut edge of the mucosa on the synthesis. So this is what it looks like in surgery.

We've made our incision along the gingiva. We've reflected the lip away, and then we're going around, we've made the osteotomy in this particular instance already. And then, this is when the bone has been removed.

And then we suture the the edge of the mucosa on the lip to the edge of the mucosa on the synthesis. So this is what it looks like and one of the pro complications sometimes that we will see is the maxillary canine is going to create some trauma to that area, but in my experience, we rarely have to do anything about it. There will be some ulceration.

To the lip and then it's as if the body will deposit some collagen and scar the area and become more resistant to the canine tooth hitting that area. Bilateral rostromandiectomy. So in this instance, as the name implies, we're gonna remove all of the rostro mandible.

And so, we, again, we're gonna go along the edge of the lip mucosa where it's close to the gingiva, go all the way around. My personal preference is even though the lip might not be involved, my personal preference is to remove a wedge of the lower lip rostrually anyway, and I'm gonna show you a picture why. And so if you do that, then you need, don't need to go all the way around.

You can cut the gingiva, then cut through the thickness of the lip. Same thing on the other side so that it's a wedge. And obviously plan things well, so you have enough lip to close, then you literally go across.

And then this is what it looks like. So as you can see, if you don't take any of the lower lip, there's gonna be extra tissue. And I personally prefer to remove it, but that's also can be done where you end up with extra lip, .

I, I, I don't know that for a fact, but maybe more likely to drool saliva, food and water, . So this is what they look like after surgery, tongue hanging, but not as bad as the total hemimandibulectomy. And then this is one that had a pretty small.

Rostro bilateral rostromandiectomy. And this is one where we removed the excess lipid, so you can see that I it's a personal bias, but I do think it looks better and that And that they do better, but again, personal bias, definitely. And then this is again, on the right, one that was more aggressive in terms of how far caudal we went.

So you can see that obviously the more cadle you go, the less support for the tongue and the more hanging of the tongue there's going to be. Versus this dog, not a very aggressive grostral mandibullectomy, easier to keep the tongue in and again I just point out that in this particular instance, the excess amount of lip has been removed so that, there's not as much skin, lip that is, creating a fold over here. Segmental mandibullectomy, again, we cut the mucosa on unilateral or I'm sorry, lateral and medial, make them communicate and then you remove that segment and then suture together.

I'm just gonna briefly mention that there appears to be More of a drive these days to maybe repair the segmental defects so that you're not gonna get what we call mandibular drift. . We're gonna see if that trend continues.

The, the argument against repairing it or, or not fixing the the segmental defect other than just by suturing soft tissue, is that, well, dogs do incredibly well without fixing it and therefore, why bring in A, a step or a technique where you need to have implants that may increase the risk of complications. Rem mandibulectomy, the idea is to basically preserve the ventral cortex of the mandible. So, from an oncologic perspective, you want it to be for small tumours that are at the gingival border, and we do mean very small with no to minimal bone invasion on imaging.

If the tumour is larger and, and goes into the canal. Of the mandible, then we definitely recommend to do a complete segmental just like I showed you. But for a small tumour that has minimal to no bone invasion, that is at the gingival edge.

Then the big advantage is that there's no mandibular drift because you are preserving the ventral cortex. So some people use a TPLO biradial saw blade, some people use a burr, but the idea again is to preserve the ventral cortex. Vertical ramus excision.

So this is where you can preserve the body of the mandible and you remove the ramus and so you can make an incision ventral to the To the zygomatic arch. Or over the zygomatic arch, one or the other, doesn't really matter where the exactly where the skin is and then remove the zygomatic arch over the ramus and then They show where different osteotomies can be done depending on where the the tumour might be and what kind of margins you need. And you basically need to dissect the, the ramus free of all of the muscle attachments.

So complications of mandiectomy include haemorrhage, so that's why I'd be prepared for having blood products more so with the caudal ones, incision swelling, you can get what we call a pseudoannula, so as the name implies, this is swelling under the tongue that looks like a rannula, but it's not a true rannula. And so, we don't treat it, we let it be, and then it will, It will resolve on its own, so it's self-limiting. Infection, in spite of the fact that we work in a non-sterile environment, as a matter of fact, it's pretty contaminated in the mouth.

We rarely see infection and the, the, the, the idea is that the mouth is so well vascularized that, it allows the immune system to come in. Very easily, and so infection is very rare. Dehisants, is a possible tyism drooling, depending on how much of the mandibula has been removed.

Tongue protrusion, I showed you some pictures of that. Mandibular drift, so when we remove One side of the mandible, then the opposite side will drift towards midline and that will cause some malocclusion and it can also cause some ulceration of the hard palate. Particularly if the contralateral canine has been preserved, then as this mandibular drift occurs, the, now the, canine is gonna go and hit the hard palate and will cause some ulceration.

There again, most of the time, in my experience, we don't need to do anything. It's gonna self-correct, and, therefore, I, I'm not a proponent of removing the tooth from the at the time of first surgery. I, I prepare owners that it's probably gonna happen, but that most dogs go on to be able to heal the ulcer and have more of a scar tissue and, and be fine with it.

And the mandibular drift, I think also might not be as severe over the long run. You can have eating difficulties, although it's not very common, but there again, you know, depending on how much of the mandible has been removed. And then in cats, grooming difficulties and that can be certainly a A quality of life issues, so cats really want to groom, and if they're not able to, some cats are gonna not be happy cats.

So how do cats do with mandibullectomy? So, this is one of the pivotal papers about mandibullectomy in cats. Where it was done in 42 cats.

And what we learned from this paper is that cats don't seem to handle mandibleectomies very well. So 72% were dysphagic or inappotent immediately in the post-operative period. 12% never regained the ability to eat.

3 of the 5 cats which never ate again had over 50% of the mandible resected. And 3 of 6 cats with over 50% of mandible resected never regained the ability to eat, so it because they were very small numbers, they could not make any kind of statistical conclusion, but certainly that would be that would suggest that if you remove more than 50% of the mandible, that could be very problematic for the cat. Cats with feeding tubes in place, were in place for a median of 74 days, so that would suggest that it can take a long time for cats to learn how to eat, and to adapt.

And so I tell clients to be prepared that it may take quite a while before their cat eats. And as far as the 12% goes, I would say, you know, when that study was done, they, they didn't know yet that cats could take so long, that it could be so hard. And therefore, not every cat had a feeding tube, and if the cat was not eating, then some owners gave up.

So it might be that the number of cats that would not eat ever again is gonna be lower than 12%. That's my my suspicion. Now that we know to put feeding tubes in, support the cats, and be patient.

Acute morbidity was seen in 98% of cats after surgery, and long-term morbidity in 76%. But in spite of that, 83% of owners were satisfied. But that paper really highlighted that mandibullectomies could be difficult for cats to adapt to.

And then, not so surprisingly, Cats that have a squamous cell carcinoma had a worse survival time than fibrosarcoma or osteosarcoma. So, fibrosarcoma The, the median. It's about right there, so a little bit hard to tell, but maybe, you know, roughly 250 days for the median for fibro or squamous cell carcinoma.

Now that we've talked about this paper, There's a more recent paper that has looked at the outcome of 8 cats with radical mandibulectomy, and I think it's, it's kinda again shifting back our perspective on how do cats do with the mandibulectomy. So, after that original paper of 42 cats, most people were pretty, well, conservative or or very very careful about mandiectomies and cats and how they would do. Whereas in this paper, and it, it, it is only 8 cats, so it's based on very few cats, however, All cats had 75 to 90% of the mandible resected.

And these authors were aware of the original paper that I presented, so a feeding tube was placed in all of them. And so that meant that they were prepared for taking over nutritional support. 6 of 8 cats ate on their own postoperatively.

And the median survival was 712 days with 7 of 8 cats that had squamous cell carcinoma. So that median is really heavily for squamous cell carcinoma, and you can see that there are cats that are live long term survivors. So that's very interesting, you know, it definitely is not the usual data that we have for survival about squamous cell carcinoma and it then also means that, well, maybe cats actually can do better, .

Even with aggressive mandibulectomies than what we originally thought. So now we're shifting back to cats can do well with myectomies, but I think that I still believe that placing a feeding tube. At the time of surgery, very important so that we are prepared to take over nutritional support and importantly warn owners that it may be 2 to 3 months before their cat eats again.

So if we're gonna do this, we have to be patient to give enough time for the cat to start eating again. Maxectomies. So the the maxilla in the dog, we're gonna first show the blood vessels, so the maxillary artery will go into the bone and go through the foramen, .

And then infraorbital foramen and then it comes out as the infraorbital artery and then you have the major palatine and the minor palatine artery, that, then the major palatine artery runs between the bone and the mucosa on the hard palate. And then just to show the maxilla and then there's the incisive bone and not that it really matters at surgery. You don't really appreciate that, that there's a, a distinction between the two bones, but just to kinda show again the maxilla, what it looks like.

So just like the mandible, there are very well-defined types of maxectomy, but realise that where you actually make the osteotomies is gonna be dependent on tumour type, tumour size, tumour location, and so, you can have a, infinite variety of what is your osteotomy looking like. But you can have rostral, unilateral or bilateral. So here is the rostral unilateral or bilateral.

It can be segmental. It can be hemimexectomy as shown over here, and it can be caudal unilateral, this is the caudal bilateral, can be cranial, unilateral, cranial, or rustral unilateral bilateral. We've talked about that.

So again, a variety of different portions of the maxilla that can be removed. So, we're gonna go through the hemimexectomy, And so we, so the principles and the concepts are very similar to the mandible, where you make an incision, . In the mucosa of the lip area close to the gingiva, and then you go cuddle to the last molar and then around the tumour and then go between the incisors and connect everything.

Elevate, and then, well, so then you remove and then it's nice to elevate the mucosa from the lip because as you pull the mucosa to create the closure, It helps to decrease how much the lip is gonna pull on the inside, but Even with good elevation, you will still have the lip being pulled on the inside and I have got pictures of that a little bit later on. So again, we have the cadaver. We make the incision, in this instance, close to the gingiva, into the mucosa and we're gonna do.

The same thing on the hard palate, and we basically connect the two and we go around the most caudal molar. And then, we start elevating, and then, And then when the bone is exposed, then we can start to make our osteotomy. And, I typically like to start the osteotomy that is on the lateral wall and then keep the osteotomy that is on the hard palate for the last one.

And if you were to make a osteotomy, so here we go around, so there's no caudal osteotomy per se, but if you were to say, just remove the rostral aspect, we keep the transverse osteotomy from lateral to medial for the end because that's where we're most likely to cut the blood vessel, and typically it's going to be the palatine artery. So we go around now, we are also doing the osteotomy in the hard palate. And then we can finish some of the areas with an osteotome.

It could all be done with an osteotome, but I think it's more difficult. And then we take the bone out. I will just point out that my osteotomy, lateral was not very dorsal.

I could have gone more dorsal I typically do. And by being more ventral in the maxilla, then I ended up being in the thickness of the bone, particularly caudally, so I ended up cutting some of their roots. But typically, we want to be more dorsal so that we don't have that issue.

We end up in the nasal cavity throughout the entire length of the osteotomy. And then we're gonna close the defect, so we're gonna take that edge of the mucosa of the lip and we're gonna bring it to that edge of the hard palate, and we can elevate the mucosa so you can see taking the the edge and we're gonna bring it and if you elevate The mucosa, some mucosa, then that will help with the tension also. And so we start to suture, like I said a bit earlier, I am a proponent of simple interrupted over here because if it dehisses, then you end up with an oral nasal fistula.

There is a a technique where you combined. You have a combined dorsolateral and intraoral approach. And we do this when, so basically what this is is we have now an incision on the On the nose and under the under the eye.

And then we make the incision on the skin over here communicate with the incision in the mouth. And the indication for that is for tumours that are going fairly dorsal. And because they're fairly dorsal, you would not be able to get the right angle to do the osteotomy from the oral cavity.

It's just to dorsal and so we have an example of a tumour here that has a fairly dorsal extent. With our margins, we almost have to be on midline dorsally and so, it's a lot easier to be able to do so from a skin incision that's Lateral dorsolateral over here and really not possible if we were to try to do everything intraoral. So here we have another example.

Note to where the tumour is and therefore, we have to make our incision further out and we cannot be close to the gum or the gingiva in this particular example. Then we make our incision onto the skin over here and then that will allow us to do the, the osteotomy more dorsal into the maxilla. And then this is the sample after it's been removed.

And then the closure, we elevate the mucosa from in the lip, mucosa to mucosa, and then we suture that mucosa to the mucosa of the hard palate. Unilateral rostro maxectomy, same principles, make an incision all the way around. We show how we are elevating the mucosa, the mucosa from the lip.

And then we are going to close the defect. And this is what it looks like once the defect is closed, but it does bring the lip in, quite a bit. So here is an example of a dog that has had the surgery and this is the cosmetic appearance and very, very common for the lower canine to be protruding out and for the nasopplanum to be slightly deviated.

So this is to be expected and something to be warning clients about. But in some other instances, that is not so severe, you can see that there's a different degree of how severe it can be. So in this instance, not as noticeable.

You can do bilateral premaxectomy, which is also called the premaxectomy or incisiveectomy since the bone is called the incisive bone. And so you basically go all the way around. This shows where the osteotomy is made.

So osteotomy across the palate. And then osteotomy across here and then down to meet the osteotomy that's go across the palate. Elevate the mucosa.

And then this is gonna close as a T as shown over here. We can put or drill some little holes to anchor our sutures into the bone of the palate. And then this is what it looks like after it's closed.

The edge of the lip over here is gonna come to midline onto the hard palate, same thing over here, and then the rest of the edge is gonna be sutured to each side such that in the end, we have a T as shown in figure G. So this is a clinical example where we've done our rostral maxectomy and then sometimes it helps to have a little cut in the mucosa here to advance to the midline, so that can be helpful and then it just shows you how it is closed as a T. One of the problems is that you're gonna have nose dro drooping.

Because there's no more bone to be supporting the cartilages. And when the dog closes its mandible, then it pushes it up, so it definitely looks better. But when the dog is panting, the mandible is not pushing it up and then the nose is dropping.

So, as you can see, it can be Pretty significant. There is a technique where you put cantilever sutures. The sutures are anchored into the nasal bone, and then they go and grab the cartilage of the plenum, and then you basically tighten the the suture such that it helps to lift the nose.

So this is my personal bias. I don't think this suture works very well. I do not like it.

Because the suture is not rigid, it doesn't really lift up the nose as shown in the picture, so the picture is not realistic. What it does is that it basically pulls the nose closer to the to the nasal bone, and so, Because it pulls it towards, so it's not as low, but then it's also pulled caudily, and they kinda have this very weird appearance in my opinion. So, you can tell I'm not a big fan.

This is my personal bias. It's described, it helps, but definitely will not look like this. It does not lift it up.

It, it pulls it towards the nasal bone, . And so, yeah, not a big fan, but I wanted to make you aware that it's out there. Here's a dog that had a caudal maxectomy, so, and it went all to midline, all the way to midline medially, so you can see that the lip is pulled to the inside quite a bit and so there again, something to prepare the owners for and then there too there can be teeth that are going to create some trauma to the upper lip.

Recently, we described the bilateral caudal maxectomy. This is showing what, was removed in one of the cases that we, reported, but the idea is that all of the caudal maxilla is removed bilaterally. And then this is showing the tumour that was removed in the CT that of that particular tumour, and then after the removal, We created mucosal flaps.

From the upper lip and cheek area to close the defect on the midline, so it was bilateral. Both of the dogs that we described had some dehants that had to have further surgery to correct, so, dehances is definitely a big problem with this, at least based on the very few cases that we've done. But the cosmetic appearance can be very, very good for these dogs.

Complications with maxectomy, haemorrhage, incision swelling, infection, same thing about infection, very rare, as I talked about for the mandible. Deissance, the big difference about dehisance and dislocation is that it almost always leads to an oral nasal fistula. If it's a small one, we're gonna let it be, it's gonna heal on its own, but if it's a large one, then it has to be corrected with another surgery.

Ulceration of the superior lip with the teeth that can be hitting the lip. They can have eating difficulties. They can have subcutaneous emphysema because now the nasal cavity has been opened up and therefore air can go when they breathe the air that goes through the nasal cavity can end up in the subcu so they can end up with some emphysema.

Epistaxis, so we end up into the nasal cavity, so they can end up with some epistaxis. And then like I showed you, the nose dropping for the bilateral rostroexectomy. There was a study that was done recently published that looked at the complications of mastectomies.

And so if we look at the intraoperative complications, the most significant one was excessive bleeding and needing a transfusion, and we can see that the bigger the tumour, the more likely there was to be Excessive bleeding and needing a transfusion, and that was clinic or statistically significant. Tumour location, so the caudal were more likely to have bleeding as well. That was significant as well.

And then the type of maxectomy, you can see that the caudal maxectomy was more likely to require and caudal and complete maxectomy, but I would make the argument that the complete is because you also have to go caudally as well. They were more likely to have bleeding and requiring blood transfusion. Was an orbitectomy performed yes or no, that was also significant.

So if an orbitectomy was performed, then more likely to bleed and that need blood. And then, whether it was only intraoral approach or the double approach that we dorsolateral approach that I, I also mentioned, that too was significant. So basically, the bigger tumour.

If the tumour affects the caudal aspect, the bigger the, obviously the bigger the tumour, the bigger the surgery. If you need to go orbitectomy, that's also part of the caudal aspect, all of that, suggests that you are more likely to bleed and need a transfusion. The complications that developed within, so post-op within 48 hours, you can see that epistaxis was more likely with the The caudal and complete mastectomy, but, you know, not very different.

Facial swelling, more likely with the caudal aspect, facial pi, not much difference between the different types. And then difficulty eating, if anything, it was the complete maxectomy that had more difficulty eating within 48 hours. If we look at more long term, From 48 hours to 4 weeks, then we see that lip trauma was more common with either bilateral or caudalcomplete.

Oral nasal fistula, again, more likely with caudal dehiscants, which goes along with having an oral nasal fistula, more likely with the caudal ones. You know, I said infection was rare, but interestingly, there were still 13 dogs that got an infection. It was more common with the Coddled and complete.

What I, I don't remember is I, I would suspect that the ones that got an infection may have been the ones that got a descent. Without a decent, my experience is that it's incredibly rare to have an infection and then epiphora. So we can see that the caudal aspect is maybe more likely to have complications both immediately post-op and then more long term as well.

Going back to cats, how do cats do we with a mastectomy? So this was just published very recently in the last year. And what we have learned is that blood loss and hypertension were the most common intraoperative complications in 17%.

Post-operative complications were seen in 57%, hyporeexia in 20% for a median duration of 7 days, and dehances in 20%. So that's similar to dogs, the dehance rate. But what I would say is that this is very different than the mandibullectomy story.

So not very many cats have hyperexia, and when they do, it is not for as long as mandibulectomies. So it appears that cats tolerate a maxectomy better than a mandibullectomy. Still a fair number of complications, but again, overall, cats seem to tolerate this better, and then when we look at the oncologic outcome, the one year survival for malignant tumours was 89% both at 1 year and 2 years, and squamous cell carcinoma, 83% at both 1 year and 2 years.

So squamous cell carcinoma of the maxilla. Appears to have a better outcome. So better oncologic outcome, better functional outcome with maxectomies and cats than mandibullectomies and cats.

And so I think that this is a very important distinction to keep in mind. So, I, I hope that you guys are enjoying the meeting and learning tonnes, and I very much look forward to, being able to meet you guys in person. Thank you very much.

Have a great day.