Good day, everyone, and thank you very much for participating in this great conference. The topic for this particular presentation is going to be hemipelectomy. So heelectomy is an aggressive surgical procedure that involves the removal of parts of the pelvis and the surrounding soft tissues.

It is an extensive, it does require extensive preoperative planning and intraoperative execution. And the first surgery is the best and really the only chance at local control for this disease. So unlike some other surgical procedures, Where it might be possible to come back and do a wider excision should we have incomplete margins.

That is not the case with hemepelectomy. Once the procedure has been done, there's really no opportunity to come back for a second surgery and therefore, this highlights the importance of planning very well before the surgery. And giving the best chances for a complete excision so that when we put a patient through this big surgery, which has a high morbidity, we can hope for the best outcome.

And yes, it, it is a high morbidity procedure. It is aggressive, but the, on the flip side, if it is indicated, then depending on the type of cancer, It could potentially be a cure. And certainly, the goal is to prolong survival at the very least, with with a great quality of life.

So, in order to perform the hemep pelectomy, it's important to be familiar with the local anatomy, and we need to give careful consideration to the orthopaedic system, nervous, urinary, abdominal wall, intestinal, and intementary systems. So we're gonna talk into more details about how these affect surgery and how do we take them into consideration. And then, in the end, we want to be able to reconstruct the defect that will have been created by removing part of the pelvis.

So the indications for hemepelectomy can be trauma, so severe trauma to the pelvis, . Either if, mostly it's because the trauma leads to displacement of the bones of the pelvis into the pelvic canal to where the animal is having a difficult time defecating, and the, it is actually easier or it's the most straightforward way to address this is to remove these bones. So that's one indication.

Osteomyelitis, at least where I work, it is incredibly rare, and therefore, I would say an unlikely, indication but can be. And then in my world, the by far the most common reason is for tumour excision. So, as far as tumours go, they can arise from different tissues in the pelvic region.

So they can come from the bone, itself, and, one of the most common tumour for, arising from bone would be osteosarcoma. It could be arising from the nervous tissue, so you can have a peripheral nerve sheet tumour and particularly one of the sciatic nerve or femoral nerve, for example, where it, it's becoming large enough that it's starting to be compromising the tissues around and the margin becomes the bone. Muscle slash connective tissue, fibrosarcoma is a relatively common tumour in that location.

And then skin fibrosarcoma again is a tumour that we see in this particular location as well. So as far as The tumours, they can be involving the proximal femur, and we're gonna talk a little bit more about that and the reasons why we would do a a type of hemepelectomy. Can be involving the acetabulum.

It can be involving the ilium, isium, pubis, sacrum that has is more, more restrictions on what we can remove as far as the sacrum goes. And then the surrounding soft tissues to where the tumour is coming from the soft tissues, but it's very large. The bones become the margins.

And therefore, a hemepelectomy is performed. And I'm gonna have some examples, pictures to show examples of how can that be? So here we are.

So, the picture on the left, dog that has a tumour of the bone itself, and therefore, being that it's arising from the bone, we need to remove the bone. So that would be a, A reason to do a hemepubectomy. And then the picture on the left is a tumour, a fibrosarcoma that does not involve the bone, but as you can see, it is so large that it comes right along the ism and in order to get a margin, then the is becomes a margin and therefore must be removed on block with the limb and the tumour.

So good example of a soft tissue tumour that nonetheless requires removal of part of the pelvis. So, when we are planning the hemepelectomy, we need to assess locally what's going on, meaning what are the tissues that are involved, what tissues are gonna need to be removed, and what will the margins be in order to achieve a complete margin. And then also what tissues are available for reconstruction of the defect.

And we're definitely gonna talk more about that as we go through the technique in terms of what tissues do we try to preserve and so we'll more about that. We also need to assess the patient for systemically for metastasis. So if the patient has Metastatic disease.

Maybe the hemepelectomy is not the Solution for this particular patient, given that we are beyond the cure and survival time is likely to be short, probably best to shift to a palliative approach. And then are there any concurrent diseases and if there are, what are they, how significant are they? Is this, for example, end stage kidney failure, and stage heart failure that would Potentially be worse than the cancer itself in terms of limiting The the survival for this particular patient.

So staging is going to be important, not necessarily part of the staging itself, but assessing the patient complete physical exam, complete blood cell count, so CBC serum biochemistry profile, urine analysis, get to see. The overall status of the patient and then most of the tumours in that location. Likes to go to the chest eventually, and therefore doing chest radiographs or a chest CT is appropriate and very much so indicated.

Abdominal ultrasound or CT of the abdomen is also indicated. So if we have, for example, a A tumour that likes to go to the lymph nodes, then that would be certainly very appropriate to image the abdomen to look at the sublumbar lymph nodes, but also to look at the abdominal viscera, see if there's any other concurrent disease that we're not aware of. And then, also to make sure, what is the body wall adjacent to the tumour for planning reconstruction.

That would be more so for tumours that are the cranial aspect of the pelvis, such as the ilium. And also tumours in the cranial aspect of the limb, such as in the quadriceps, for example, and not so much for tumours that would be in the is or in the semitendinosis, semi-embrinosis that are more caudal. So, Body wall in terms of assessing it, will be dependent on location of the tumour in the hind limb and in the pelvic area.

And then, although this is not commonly available, a PET CT is a great way to get a full assessment, . Of the entire body, with the PET, positron emission tomography and then the CT as well. Very important, to get an idea of what the tumour is so that we know what the biologic behaviour is.

So, needle aspirate can be done and oftentimes will be enough information to know what the diagnosis is. So, needle aspirates may be able to tell us that this is a sarcoma, may not be able to tell us what kind of sarcoma. But once we know it's a sarcoma, then we have enough information to justify doing a hemepelectomy, obviously with owner's consent.

But if the owner needs to have more information to have a, even more accurate idea of the biologic behaviour and the needle aspirate was not able to provide that information, or if the needle aspirate was non-diagnostic, then a biopsy is very much indicated. It can be incisional or a bone core as far as the Biopsy of soft tissue goes, we can do it with a different means, one of which can be the true cut needle core biopsy as shown on the right to top right. And if it is a bone biopsy, then either a refine, Or a jam sheety needle, we do not favour the she find anymore for a couple of reasons.

One, it's a large bore, which is fine in terms of getting a great sample in terms of size, but if it's a, weight bearing bone, then that can lead to a fracture, even if it's non-weight bearing, so such as the issue, for example, still can fracture, . And then, the tip is not tapered, so my experience has been that you put the instrument into the lesion and then there's nothing to really help keep the sample inside of the instrument. So oftentimes when you come out of the lesion, you are, you have an empty instrument.

The core has been left behind. Whereas the jam she is smaller diameter, so less chance of a fracture, and the end is tapered, which helps to keep the sample in the needle. It certainly does happen where the sample does not stay in the needle, but in my experience, it happens less frequently than with the refine.

In the preoperative planning, this is one procedure where you absolutely want to have advanced imaging, radiographs is not adequate and ultrasound is not adequate either. So it's either CT or MRI, and for me, CT is my preference mostly because this is what I'm most used to, but MRI could also be a great way to image. .

Without a 3D imaging such as CT or MRI there is a great chance of underestimating the size of the lesion and by doing so, then not being able to achieve complete margins and maybe going to a surgery where it would not have been indicated to begin with. So this is a great example on the slide. Tumour of the wing of the ileum that goes all the way to a lumbar vertebra.

So, getting margins here is pretty much gonna be impossible and therefore we need to know this ahead of time, that if we're gonna do a hemmielbectomy, we're likely to leave tumour cells behind. Which in itself, like I said earlier, we, we definitely want to try to get complete margins so that we can achieve a local cure, . But that in itself may not be a reason to completely say that hemepelbectomy is not, cannot be done.

You could still do a hemepelbectomy and then follow with radiation therapy depending on the tumour type and the circumstances, but something that best to know ahead of time so you can plan the surgery. And know that the prognosis is gonna be different, the treatment plan overall may be different. All decisions that the owners are Better to, to, to know this ahead of time.

In preparation for the surgery, we wanna put a urinary catheter in, for what I call or refer to the small hemielectomies may not be necessary. So, for example, an acid tabulectomy, I don't think the urinary catheter is absolutely necessary. But the bigger ones, and if you have any doubt, very important to know where the urethra is, and so really the urinary catheter, it's primary goal is to be able to identify the urethra at surgery and make sure that we're not going to damage and traumatise the urethra.

Purse string in the around the anus, great to keep the field as clean and aseptic as possible. If we are going to remove part of the muscles that are on the medial side, such as a coccyle and leva for ani, then having a syringe case in the rectum, again, the purpose is to be able to identify the rectum. So, that's a great way to be able to easily identify the rectum, but if you're not gonna be removing these muscles, then it's not, again, it's not a necessity.

And then patient preparation, anaesthesia, the instrumentation to be able to monitor the patient very well, ECG and then blood pressure as blood loss, and significant blood loss can occur and being able to monitor the blood pressure is gonna be very important. In preparing the patient, we want to clip the area very widely and more so than what you think. And so always go beyond what you think might be required.

So this is a good example where the The wing of the ileum is probably at this level over here, but then the clip went all the way to the ribs. Again, as we pull skin and maybe even harvest skin with flaps in different locations, we want to have all of that available. And so as I just said, include regions where tissue may be brought in to reconstruct a defect.

Obviously, aseptically prepared the area and then the patient is placed in lateral recumbency. And always best to have the limb available at surgery as opposed to being under the drapes. So again, there can be some exceptions, but I think it's very nice to be able to manipulate the the limb absolutely, absolutely necessary for A total hemepelbectomy, maybe not absolutely essential.

For an ileectomy or maybe not an ectomy, but again, best to have it available to where you can manipulate it at surgery. So there are different types of healectomy as I've kind of been alluding to. There is the total hemepelectomy, which, as the name implies, removes all of the ileum acetabuloin isium.

Here, the osteotomies were made through the operator foramen, but an absolute complete hemepelectomy, you can go on the synthesis or on midline, so, And we're gonna talk a little bit more about that, the pros and the cons of doing so. You can do a partial mid the cranial, so in this example, it is the ilium and the acetabulum that's been removed. You can have a partial midcaudal towards the isium and the acetabulum that's removed.

You can have a caudal which is part of the ism. And then, these diagrams just show the different areas of the pelvis that can be removed. And I think it's important to realise that there really are a lot of different combinations possible and I think that as you will see at the very end, we're gonna, we as a profession are probably gonna start pushing the envelope a little bit about what can be done.

So over here in A on the left. Complete hemielectomy as you can see shown on the synthesis. This is a midcaudal with the isum and the acetabulum, midcranial with the ileum in the acetabullum, and then the isectomy in the.

And then the picture on the right are different representations of different types of hemepelectomy. That have been reported in the, in one particular paper by Doctor Straw. So we can see that there are different way or different portions that can be removed.

One thing that I will point out right now is that If you remove and we'll, we'll talk about that a little bit more. But if you remove the weight bearing axis, then that So far, typically will imply removing the limb as well, so we end up with an amputation. So for example, here we have a Removing the ileum and therefore amputation was done as well, removing the ileum with part of the acetabulum with the acetabuum and and then the limb was removed.

In this particular example, the only time where the limb was not removed is when an isectomy was performed. Otherwise, an amputation was already, it was always performed. So, we're gonna start with the acid tabulectomy.

That's kind of the smallest of all of the hemielectomies. And Really, an acid tabulectomy is a wider amputation. And the reasons why we would do an acetabulectomy is could be a small tumour of the acetabulum itself, but that's pretty rare.

Usually, tumours of the pelvis are gonna be larger and we need to remove more of the pelvis. A true acetabulectomy is typically performed because of a tumour that involves the proximal humerus, or I'm sorry, the proximal femur, that is, I'm sorry about that. And the acetablectomy achieves two goals, and obviously the aciabulectomy is performed with The amputation So mostly, if anything, because the tumour is in the, is in the femur so it needs to come out.

So it will allow you to achieve better soft tissue margins, instead of disarticulating and cutting your muscles, namely the gluteals, for example, close to the femur. Then you can go further out into the gluteals and and therefore achieve better soft tissue margins. And then the other reason is that we always say osteosarcoma rarely goes across a joint.

But there are two joints where it can do so. It still is rare, but the two joints where it can do so are the stifle and the coccofemoral joint. And the reason is that there is an intra-articular ligament in both of these joints and the stifle, it is the cruciate ligaments.

And in the In the hip, coccofemoral joint, it is the ligament of the head of the femur, and these ligaments attached to the subcontral bone on either side. So that means that there is a little defect in the articular cartilage to allow the ligament to go through. And the ligament can act as a scaffold for the tumour, if the, if the tumour grows and then the cells go to the attachment of the ligament in the subchondral bone.

Then as the cell divide, then they can grow along the length of the ligament and then go on the opposite side. And so for that reason, when we have a tumour of the proximal femur, then at sometimes rarely, we'll see changes on the other side of the joint. But even if we don't see changes on the other side of the joint, we assume that there could be microscopic extension and we're going to do an acetabulectomy.

So, as shown over here, we have the pelvis with the hind limb and then we basically do our osteotomies are going to be cranial to the acetabulum, so in the body of the ileum, always be very careful that you palpate the sacro sacroiliac joint that you find the caudal aspect and make sure that your osteotomy is caudal to the SI joint. Then an osteotomy in the pubis and one osteotomy coddled to the acetabulum into the ism that goes into the operator foramen. So that's the acid tabulectomy and again, just to re-emphasize that in the, your soft tissue, you can cut higher into the gluteals and that gives you better margins.

So, we've covered the hemepelectomy and now, or I'm sorry, with the acetabulectomy, and now we're gonna go to the total hemepelectomy. We're not gonna have the time and the scope to cover all of the different types of hemepelbectomy. Meaning ileectomy, isectomy.

So by choosing the hemep pelvic, the total hemepelectomy, then that allows us to discuss the approaches and the decision making of the cranial aspect, medial aspect, caudal aspect, so that if you end up doing a smaller hemepelectomy, then at least you've heard the discussion about the different compartments of the hemepelbectomy. So, for the complete heelectomy, we will have to address the ileum, the pubis, and the ism. The limb is going to be amputated as well.

And then it may include portions of the sacrum and vertebral bodies. So at that point, I mentioned to you a little bit earlier that the sacrum is limited. So on the sacrum, We can really remove the lateral third of the sacrum is what we say.

It basically takes you to the level of the foramens in the sacrum where the nerve roots are coming out, and And going any more medial, then you're gonna start sacrificing the the nerves, and certainly, You don't need a femoral nerve, but that would not be at the sacral level anyway. But to make your point, you don't need a femoral nerve. You don't need a sciatic nerve.

You don't need an operator nerve if you have an amputation. The limb is gone, so these nerves would have no purpose, but it's really the preendal nerve that is important to preserve, and so we are limited to how far medially we can go, and again, the, the Recommendation is to to not go more medial than the foramens that allow the nerve roots to come out. Vertebral bodies there again, you know, we're limited in or in, in what we can remove.

We can certainly remove the transverse process, for example, but as far as the vertebral bodies go, challenging and I mean, you can really think of crazy surgeries and you can push the envelope and it, it can be done. But then you need to consider that the, the spine will be destabilised and that will have to be re-stabilized in, in some form. So, not something that is done commonly.

And then really a total hemepelectomy is really, you know, it can certainly be intimidating, but if you think of it, it's really a glorified amputation, to where it's performed more proximal, and then what I call the medial aspect is new. So what I mean by the medial aspect is that Dorsal area, medial to the ileum, medial to the acetabulum, and on the isium, that's a part of the amputation that you, you don't see with the coccyofemoral disarticulation. Whereas otherwise caudally and cranially, depending on the level that you're at and we're gonna show what I mean by that, then, you know, It's really not all that different than a, an amputation.

So again, it's a glorified amputation as far as the total hemepelectomy goes. So there are different ways to think about a hemepelectomy and There are different philosophies as to how to see it, and so I'm just gonna show you one way, but, ultimately, what you need is an incision that's going to be circumferential around the limb, just like an amputation. But it's gonna be bigger.

And so you can think of it as either an encircling incision that goes around the limb or three converging skin incisions. There's gonna be the ventral one that is medial to the limb. There's gonna be the caudal one, and then there's the dorsolateral one.

And then the ventral one and the dorsolateral, they, they go cranially and they, they meet cranially. So these incisions all come together and, and yes, it, you know, it's not three separate, they, they converge together, but these are maybe different compartments that you can, address, one step at a time, but eventually they all run into one another and like I keep saying, it is a glorified amputation. So, the, in the planning, the first thing is to plan the skin incision, and we, we want to have adequate margins, but we also want to have skin that we will be able to close the defect.

And whereas we may not always have muscles to close the defect under the skin, skin, we absolutely need it. So we, one way or the other, we're gonna have to have skin and you can also harvest skin from the belly, you can do skin flaps, but it turns out that it's, it's rarely necessary to have a true skin flap. And in essence, we create a skin flap with our incision.

And so what I mean by this is that the pictures are a great example. So This is a cat in lateral recumbency. This tumour is over the hip, the hind limb is going down here.

And so we are taking 5 centimetre margins from this vaccine or injection site sarcoma. So we're gonna take our 5 centimetres all the way around for our margins, and then this is where it goes. But then, in order to close the defect on the medial aspect of the limb, so here's the medial aspect, we can preserve all of the skin here.

So it is in essence a form of flap, . But we are saving it from the limb. We are on the opposite side of the of the tumour, so it's very, very safe in terms of margins.

And so typically we always say, Most of the time, you're able to save skin on the opposite side of the tumour. So this is a great example. The tumour is lateral and dorsal, so we can save skin on the ventral and medial aspect.

Other examples, similarly here, we have a tumour that is on the kinda dorsal caudal, so we're gonna preserve skin on the cranial medial aspect. So we're gonna save that skin here so that we can use that as a flap. Another example, tumour that is on the caudal aspect.

So we're saving skin on the cranial aspect. And then here, just showing that we, we are going cranially, but then we would save some of the skin caudally to be able to to close this defects. So different, the location of the tumour will dictate our margins and then we also dictate where can we save skin, that being what what I will refer to as the on the opposite side of the tumour.

So, we're gonna start with our ventral approach. We will need to do a dissection to the level of the pubis. And and we will need to transect the pre, so here's the pubis and the finger goes from cranial to the pubis to the operator foramen.

And so we've we've dissected down to the pubis, we've elevated over the pubis. And we also need to cut the prepubic tendon. So that is where we are compromising the integrity of the, the abdominal wall.

And when we're gonna be closing, we're gonna have to reconstruct that abdominal wall so that organs don't herniate, particularly the bladder that lives caudally, but it could also be, intestines, . So we wanna reconstruct the abdominal wall at the very end, but we're not there yet. So we're going to cut the prepubic tendon and we're gonna elevate or elevate it.

And then, as far as where do we cut the muscles, it will depend on where the tumour is. So if we go to the picture on the right, If we have a tumour that's more dorsal or more lateral, then we can do our osteotomy more lateral, that's gonna go through the operator foramen. If the tumour is more ventral or more medial, then we're gonna have to go on the synthesis, and that will dictate what muscles need to be sacrificed versus those that can be preserved.

So if the incision is more lateral, then we can preserve muscles that have their attachment. Onto the pubis and is more medially. So gracillis, for example, semitendinosis, semimembryosis can be preserved.

If we are away from the tumour again, it all depends on where the tumour is. Whereas if we cut on midline, Then we really are not able to preserve any muscles and that can lead to a situation where when we're gonna, after the hemepelectomy, when we close, we literally have no muscles to work with and it We're gonna be closing subQ and skin right over the rectum. It's not very common.

We typically are able to save some muscles somewhere, but there are some rare instances where the rectum is right underneath the skin. So, we're gonna try to preserve as much and as many muscles as we can, but our ability will depend on where the tumour is, what our margin what our margins are, and where we need to cut. On the, while we're there, eventually, we're going to transect the operator nerve and you, we can infuse with nocida or bipivicaine before we transect it.

Nocida is a liposome encapsulated bipivicaine that is released over 3 days, so, that works very, very well. And then, This is also where we can ligate the femoral artery and vein, and we can transect them. For most tumours, the femoral artery, the femoral artery and vein are gonna be transected very much like a limb amputation.

However, for the tumours that are close to or that are in the femoral triangle, then we cannot go and ligate the vessels in that typical location and we're gonna have to go and ligate at the level of the external pedental. So what we do is that here we have the femoral triangle. This is where we would ligate the femoral artery and vein.

But instead, if the tumour is here, then we're gonna have to go more cranial and more medial, and then we can ligate the external iliac arteries and vein. We will want to preserve the internal iliac, but that, that would be even, that would be where the trifurcation of the aorta is. We don't need to go that far.

To be able to ligate the external iliac. It's gonna be accessible further caudally. In order to have access to the External iliac, it's basically gonna be in the location here.

So we're gonna have to also get rid of the psoas major muscle. So psoas major is here and then we have the iliacus which forms in the ileosoas which you remember attaches to the lesser trochanter. So, because we're doing a hemmielectomy, unlike the amputation where we can cut the iliosoas close to the lesser trochanter.

In this instance, we wanna be, and, and the tumour might be in this location, so we're gonna have to go and cut it more cranial, and then as we cut the attachment of the body wall to the pelvis, that will give us access to the iliac artery in this particular location right there, so that we can stay away from the tumour. But even, even if we don't need to ligate at the level of the external iliac, we still need to cut the psoas muscles at any rate, so that we free up the limb and be able to have the limb come out with the pelvis. And then Preserve as much as the of the body wall as you can, but again, if the tumour is right there, you're gonna have to sacrifice some of the body wall.

So, tumour location, I, I keep repeating it, but tumour location is what dictates where we make our cuts, but always preserve as much muscles as you can safely, with your margins taking precedence. And then we're gonna do the osteotomy. Again, we had the discussion as to whether, depending on tumour location, whether you could do the osteotomy, that's gonna go into the optra foramen or whether you need to go on the synthesis.

Here we have the finger into the under the pubis, into the operator foramen and then we would put like an army navy. As a retractor under to protect the tissues so that when we cut, we are protecting the tissues underneath. It can be done with the oscillating saw, in my opinion, a lot easier, a lot faster, but it can also be done with an osteotome.

So then the the ventral incision extends caudally. We are going to protect the colon and urethra. Those are obviously gonna be dorsal to the isum and to the pubis.

We have a urinary catheters and a landmark to be able to find the urethra and then a syringe case in the rectum to be able to find the rectum. And we want to preserve the pedendal nerve and its colorectal branch so that we have full function of the rectum and anus as well and the sphincter. We kind of touch upon this, a little bit earlier.

We wanna preserve the caudal musculature as much as we can. So gracillus abductors, semimembranosis, semi semitendinosis. Again, if the tumour is cranial, we can preserve a lot of these muscles.

They can be cut mid belly to even a bit more distal, but if the tumour is right here, they're gonna have to be sacrificed. So again, if appropriate, possible. Depends on the level of osteotomy, medial to lateral as well.

So, if your osteotomy is on midline, you will not be able to preserve the attachment of the muscle and so even though you say, well, the tumour is not really here per se, but I need to make my osteotomy here, then you, you sacrifice the attachment so you won't be able to preserve those muscles. So preserve what you can. Which is appropriate to the location of the tumour.

Preserve the operator muscle again if possible for reconstruction. And then again for the isium, you can go through the operator foramen, so you can make an osteotomy that is more lateral than the synthesis, but if the tumour dictates, you would go on to the synthesis and not through the operator foramen. So, now we're gonna go to the dorsolateral and remember the dorsolateral aspect is also going to meet the ventral incision cranially, so those two compartments are going to meet cranially.

So you're gonna connect the ventral and caudal incisions at the dorsolateral aspect, and this will provide exposure of the dorsal portion of the ileum and ileal crest, and then that will also, by elevating the sacrospinalis muscle that will expose the sacroiliac joint and we need to go to the sacroiliac joint. Both femoral and sciatic nerves are isolated and transected. The femoral nerve comes out of the spine more cranially, so you will have the femoral nerve be more distal to where it comes out of the spine.

A great landmark to find the femoral nerve is it runs with the ileosoas muscle. So, it will be right next to that muscle and then the sciatic nerve, you can You can identify it and isolate it medial to the ileum. And then you can, once you find it, you can infuse it with the pivocaine.

It can be the Nositta, and then you transect it. And then we need to disarticulate the sacroiliac joint, can be done with the osteotome or can be done with a oscillating saw. The disarticulation does not have to be perfect and as we have talked about, you can go into the sacrum about a third of the way the foramens are going to be your landmark that you don't wanna go medial to that.

And you can either do it from a dorsal direction, but you can also do it from a Ventral direction as far as the disarticulation goes, kind of a personal preference. I think it, it works well either way. So you can, again, do it from going from ventral to do to dorsal or dorsal to ventral.

And so here we have the the disarticulation, this is the sacrum over here and then the the pelvis is starting to be able to be pulled away from the body. And then there's gonna be some muscles that are gonna remain attached while we're are here, we're gonna talk about the body wall. So the, the oblique muscles such as the internal and external oblique muscles and then on the medial aspect on the inside is the transverse muscle.

As you can see, they have their attachment to the vertebrae. So, part of the tendon is gonna go to the spinous process and part of the tendon is gonna go to the transverse process. But as we go more ventral then, they will also have the prepubic tendon as well.

So as you remove the wing of the ileum, then you're going to have to cut the attachment to the ileum going towards the the pubis. And then, We also need to address the sacrotuberous ligament in the dog. So, as you are working dorsally, then you can go ahead and cut the sacrotuberal ligament that has to be freed up so that the pelvis can come out.

And then on the middle aspect, I just wanna maybe go back. To the, the, I, I haven't really, addressed this, but in the Ventral, and also as the dorsolateral as they meet cranially, you're gonna also have to take care of the muscles that are at the cranial aspect. And so like If you are not removing the wing of the ileum, then you would have to cut these muscles, such as tensor fasciata and dissartorius.

But because we are disarticulating, then these muscles don't need to be addressed because they're coming out. So, the level of, of your hemepelectomy will also dictate what muscles need to be cut or not. So We go back to the medial aspect now.

So we need to, so basically all of the muscles that are extrinsic to the pelvis will need to be cut, and then all of the muscles that are intrinsic to this pelvis, hind limb do not need to be cut. And so here on the medial aspect, we have coccygeous and evator anni that attached to the coccygeal vertebrae and then they attach to the medial aspect of the of the pelvis. And so if you have a tumour that is more lateral, then you can cut these or even elevate them because your bone is your margin, so you can elevate them and preserve them to cover the rectum.

But if the tumour is also involving the medial aspect of the pelvis, then you're gonna have to cut them higher up. So, but one way or the other, these need to be either elevated or cut. And so we can see the muscles that are attached to the medial aspect of the pelvis.

These muscles will also have to be cut, to be able to remove the pelvis, but we mentioned cutting the sacros spinalis, and then the quadritis labrum will also have to be cut, iliacus and then the coccyous and levator ani are also gonna have to be, Cut as well, and they're either elevated or they are cut depending on where the tumour is. So this shows when you cut these muscles, if you cut them higher up, because that would be when the tumour is more medial, then right medial to that is the rectum. So just be aware that you absolutely want to know where the rectum is and that's why having a syringe case can be very helpful.

So then, then once all of the soft tissues are also transected or elevated, we've made our osteotomies at the sacroiliac joint. We've cut the pubis, the ism or on the synthesis, then. The pelvis with the limb comes out.

Mark the margins for surgical margins to help the pathologist know where the margins are, and we can do that with ink. And then in the dog, we could put hema clips to show where the tumour bed is so that if there was some Radiation therapy that would be done, knowing that depending on what you removed and how close the rectum is, that may and also depending on the type of radiation that may or may not be feasible or can have some serious side effects for the rectum. But at any rate, you can put hema clips to show where the surgeon was so that the radiation oncologist has a better understanding of where the surgeon was and make sure that that's included in the radiation therapy field.

Reconstruction, so we need to reconstruct the abdominal wall so that things don't herniate. And we are going to use the muscles that are available. So, Saving as much muscles from the limb, and their attachment to the pelvis is very helpful.

That can be sartorious, that can be a combination of gricillus abductor or operator muscles, but again, it depends on whether or not you were able to save this. Otherwise, we're gonna have to use the oblique musculature in the internal Well, external and internal oblique and then the transverses to be able to correct the defect and make sure that we are able to close this and then some cases we might need to use a synthetic mesh. So for tumours that are closer involving the abdominal wall, I think it's essential to have a synthetic mesh available for plan B.

I try to avoid using a mesh as much as I can, but if it's the only way, then we will use a synthetic mesh. And then, as always, try to avoid excessive tension so that things don't dehiss. So try to move muscles around as much as you can.

But as I was saying, there are cases where we reconstruct the body wall and then there's nothing to cover the rectum. All, all that it's going to be is gonna be the skin. And then, but the skin must be closed, so hopefully you have planned things very well before making your skin incision and you were able to save skin where it was appropriate so you can use that.

But sometimes you might need to use an axial pattern flap and the caudal superficial epigastric is right in that location. So that might be a good flap, but it turns out that it's rare. We are usually able to save skin somewhere and and then because the pelvic, pelvis is gone, then the skin, it doesn't have to go around it, so it's easier to go and reach the opposite side.

So it turns out that flaps are actually rarely required. Other, other than the skin that you were able to preserve. So here we have a male dog with a catheter into the penis and then you can see that we were able to save skin caudally that went and closed the defect.

Here we have another example, skin that was saved medially, and this is a female dog with her vulva, so we were able to save skin medially to close the defect. Postoperatively, we wanna have good analgesia. This is an absolute requirement.

So preemptive injectable opioids, fentanyl, or other opioids. We're gonna use CRIs of fentanyl, like I said, ketamine and lidocaine are also very good. Epidural either pre or postoperatively, you, you could even have a, epidural catheter.

And then, now that the liposome encapsulated, the pivocaine is available, I have to say that it really has changed our ability and the way that we provide analgesia, . We, I would not use epidural catheter, myself anymore and those infusion catheters in the wound. We don't use that anymore.

I think Nocita has revolutionised these, with good, good, distribution of the Noceta into your wound. You can get great analgesia. For 3 days and then after that, the, the pain of surgery will be greatly subsided typically.

So, that is a great way to provide analgesia. And then an NSAID, if appropriate, we will use a lot of NSAIDs in our patients again if appropriate. Post-operative care.

So, we need to be aware that this patient is gonna be recumbent, it's gonna be sedated from all of the analgesic drugs that we're gonna give. And so we need to make sure that we provide good bedding and prevent a decubital ulcer. Urinary catheter is also very helpful to make sure that the patient does not urinate.

On itself and then get the urine scalled and potentially on the incision. Make sure that defecation, when the dog does defecate, that it's cleaned rapidly, so no urine, or I'm sorry, no irritation of the skin and no contamination of the incision. IV fluids to keep it well hydrated, nutrition, have it eat as soon as possible.

If the dog does not want to eat, it might be worthwhile to consider some, tube feeding, . And not necessarily a gastric or esophageal tube, but it can be like a nasogastric tube, for example. And then, like I said earlier, padded bedding.

And then we can help the patient learn how to get up. Sling walking is important. And like I said in the beginning, all of this is really like a glorified amputation.

It definitely is more morbidity, and I think that subjectively dogs may take a little bit longer to, get up. Maybe they're controlling the pain is A little bit more difficult, although again with Noida, we are doing a very good job, but it's really just like an amputation. Some dogs are gonna get up after a hemepovectomy and on their own and walk, particularly if they were not using the limb to begin with, whereas dogs that have very good use of the the limb, they're gonna be probably need more assistance.

Complications, Descent, hematoma seroma, the hematoma seroma, that's Almost a given, well, not the hematoma, but the seroma, that's almost a given. Hernia formation, we talked about the importance of reconstructing the body wall to help prevent that. But if it's not done well or if there's the hissence at the abdominal wall level that we can get a hernia.

For those dogs that the levator ani and coccygeal muscles were sacrificed, I always worry about some form of perineal hernia, and I, I would think that that could happen, but I've never seen it. So, perineal hernia, I've never seen that happen in spite of the fact that we sacrifice the pelvic diaphragm in some of these dogs. Infection, pressure sores.

Urinary and rectal related dysfunction, so because the nerve supply is there, potentially urinary retention or incontinence, and then also, You are faecal incontinence. These are rare, and then, unfortunately, tumour recurrence is a possibility as well. Clinically, I think that yes, hemepelectomy is a radical surgery but it can result in very good local tumour control.

As a matter of fact, it can result in a local cure. Patient selection is key and therefore, 3D imaging such as CT and MRI are essential because sometimes what you see on your physical exam is the tip of the iceberg. So, To be able to select our patients very well.

We need to know the full picture, so 3D imaging. And then excision of the hemi pelvis with an eye on reconstructing the defect will contribute to the success. So again, don't compromise the margins, however, plan things well to help yourself in the reconstruction.

And then, in terms of cosmesis, they really don't look much different than an amputation. As a matter of fact, it's hard to tell the difference between a hind limb amputation and a hemepelectomy, so this is what they look like. I just want to bring your your attention.

There's been this paper that's described an ileectomy with limb preservation for a dog with an ileal osteosarcoma, surgical description and a case report. So the ileum, if you remember, is part of the weight-bearing axis. So when the limb goes down, the weight of the body is supported mostly by the spine and then the, the weight goes through the sacrum SI joint.

Body of the ileum, acetabulum. Coccofemoral joint, femur, and then down all the way to the foot. So this is how the weight is supported.

So the ileum is how the weight and the forces are transferred. Into the limb. So if you sacrifice that, then theoretically, you should not be able to preserve the limb.

But that's always been questioned, and the question is, well, can you preserve the limb and if you sacrifice the body of the ilium, then the weight would be transferred from the limb through the isium and pubis or part of the pubis and then to the opposite side. So, this is what's been done in, in this particular case report, they removed the ileum, and the wing and the body of the ileum so that the SI joint, it does not exist anymore. So, in this particular dog, 8 days after the surgery, there was a fracture of the ism which would suggest that The the is is obviously not designed to see these kind of forces, and so it has led to a fracture, but interestingly enough, they treated this conservatively, the dog went on to heal and do very well.

So it is possible to sacrifice the weight bearing axis with the ileum. And then, preserve the limb, and then your forces are gonna be transferred to the contralateral side, knowing that a fracture is possible. But then Wolf's law would say that over time, if it hasn't fractured or even after the fracture, once it's healed, then these bones should hypertrophy to be able to accommodate the excessive forces or increased forces.

So in this particular paper, they said that to their knowledge, this was the first time that this was done, where the ileums were sacrificed and the limb was preserved. And although this is very different, the concept is similar. This has been reported in 1979, so the idea of removing the weight-bearing axis and preserving the limbs certainly has been done.

This is even a little bit more excessive in my opinion. So this is really an acid tabullectomy, a big acid tabuectomy, where they've removed the acetabuum part of the ism and part of the ilium, but it's really an acetabuectomy. So, what they've done, because the acetabulum is gone is they've, they've also done a femoral head and neck excision.

So that this dog now has an FHO with the acetabulectomy and all that's keeping this leg attached are the muscles. And so it's pretty amazing when you think about it. And then you might wonder, well, how did this dog do?

And the comment that they make is that the dog made an even full recovery following the subtotal hemi pelectomy and was weight bearing on the operated limb when examined 2 weeks postoperatively. So 2 weeks later, the dog is weight-bearing. The dog at times tended to walk on the dorsum of the right pod, the result of a probable asiatic or sciatic nerve injury.

So the sciatic nerve runs right along here, so they are, Saying that during the surgery, they probably damaged the sciatic nerve. But despite this handicap, the dog lived an active life and had not experienced any further bouts of constipation, so the, the surgery was done for trauma, purposes and the dog was constipated. Until she died of unrelated causes two years later and again, they seemed to indicate that limb function was good.

So, so as I was saying in the very beginning, you know, we, we may be starting to push the envelope in terms of what parts of the, of the pelvis we removed and whether we saved the limb or not. So we may not Always do an amputation as we have done. And I think that as time goes, we will see whether this is a good idea or not.

So certainly not for every owner, definitely requires an owner that is willing to in some ways gamble and take that risk. So, this is all I have for the hemepelectomy. Thank you very much again and I certainly hope to be able to see all of you in the near future once the world returns to a more normal state.

Thank you and have a good day.