Hello, everyone, and welcome. I'm Matteo Senese. I'm a senior lecturer in small animal surgery and head of soft tissue surgery at the Royal Veterinary College.
Thank you very much, to the vet webinar vet for the invitation, and today we're gonna talk about managing urethral and urethral diseases in cats and dogs and what's new. We're going to divide the lecture in two parts, ureters and urethra. So we gonna start with the, with the ureters.
The ureters are tricky structures for their positions. They are very small and as you can see, they are in a retroperitoneal space, so very deep into the abdomen and very dorsal position covered by all the abdominal organs. They are fibromuscular tubes.
They, as you know, they connect the kidneys to, to the urinary bladder. The length and the diameters is well animals has always been poorly documented because I guess it's difficult to do anatomical, studies from this perspective, but we know roughly that in cuts, the diameter of the, ureters are 0.4 of a millimetres, so very small.
In dogs, we have some imaging studies based on CT scan mainly. So we know roughly the, in dogs between 2030 kg, and, and ureter diameter should range between 2, 2.5 millimetres, so still quite challenging from the surgical perspective.
In terms of position, if you want to evaluate the, the ureters during surgery, what we need to do is reflect the bladder in a caudal position. So, here, remember, both pictures cranial is to the left. So we see.
With the bladder reflected out of the abdomen, you see these two structures, the linear structure, if you can see the, the arrow that run into the, the abdomen with some fat around some ligament, those are the, ureters. And I think it's nice to get used to recognise them during an, an exploratory laparotomy. If we're not sure about it, we try to look from the kidney perspective and we try to follow from the renal pelvis and, and then try to find the ureters there.
This is just a simple picture to show in cuts with metal in blue inside, as you can see, quite tortuous, very, very, small and difficult to deal with. We can do some imaging, and, here we have 3 different types, obviously playing radiographs, potentially they're not very helpful, . To see the ureters is actually impossible to see the urethra through a, just the plain radiographs.
You may see some stones, some mineralization where potentially the ureter should run so in a very dorsal position caudal to the to the kidneys, or we can do some IV urography, for example. So in that case, we inject some contrast. Intravenously and then we wait for the excretion of the contrast through the renal pelvis as you can see in the middle picture and the contrast that goes down to the ureter till we found some contrast and we can find some contrast into the bladder and so they show patency of the of the ureters otherwise on the right hand side we have some an integrade pyelograms so in that case, .
We basically, we can stick a needle inside the renal pelvis and this one can be done ultrasound guided. We inject the contrast, we can use radiographs or fluoroscopy and we can see how dilated potentially the, the renal pelvis is and it's so hydronephrosis. And if we have hydroureter as well, so dilation of the ureters and as you can see on the, on the left.
Side picture you don't see any more contrast going down the ureter so you can suspect an obstruction at that level. You can also use a nephrostomy tube, maybe it's overkilling, but maybe you use a nephrostomy tube to relieve an obstruction and by sometimes in that case you can inject some contrast through it and try to find out a possible obstruction or any urethral disease. Retrograde urethrocystography obviously is not to highlight the ureters, not for to study the, the ureters or look for any obstruction, but sometimes when we want to evaluate the bladder and evaluate the urethra, some of the contrast actually goes into the, the ureter and as you can see in this picture.
It goes into the the renal pelvis. As you can see specifically in this picture, remember that the ureters should insert in a called the dorsal direction into the the urinary bladder and in this case, it looks like the urethra is actually bypassing, the, the urinary bladder, so potentially we're dealing with an ectopic ureter here. Ultrasound is something that, I got used to it and it's actually a very simple modality, even if you're not an expert.
So with the ultrasound, you can, evaluate if the renal pelvis is, dilated or, or not. As you can see on the left-hand side, there is some dilation, and you can actually see the ureter coming out from the renal pelvis and you can see that it's quite Dilate and obviously you have a, a, a similar picture, from the radiograph perspective with the, where you can see a very big dilation of the of the renal pelvis, a very dilated ureter and at some point is the contrast stops. So again, you can argue that there is a possible obstruction.
So, now we're gonna talk about urethral obstructions specifically. It's a very complex process and it's very important to know the potentially the duration of the obstruction and the degree of the obstruction is. Partial is complete and we need to bear in mind that also when we relieve the obstruction, the changes continue to occur, especially to, to the kidney.
So we won't be able to know how the kidney recovers straight away. We need to be more time. What are the most common causes of obstruction, in, in our patients?
By far, urethrolithia this is the most common, so have a little calcua. You, you can see the two pictures on, on top, and you can see several calcula on the left hand side, along where the ureter is supposed to be and on the right hand side, you can see the placement of, of the stent. So the stent is bypassing the obstruction, but you can still see, see all the calculi.
Urethral strictures, strictures usually are secondary to something, either a trauma or hyatrogenic or maybe there was a stone lodged there that it got displaced and now maybe we have some scar tissue and we have a new obstruction due to a stricture. Neoplasia at the level of the trigon. So, at the level of the urethral vesicular junction, so where the, the, ureter enters into the bladder.
So we could have an obstruction that, at the level, or we can have, as you can see in the, in the true picture on the left, left hand side, we could have a circum caval ureter. So this is an anatomical problem with the ureter wrapped around the, the caudal in a cava. We can attend medical management.
I'm not the best expert talking about medical management, so I'm gonna briefly mention it. We need to remember that the majority of the calculate are cat oxalate, especially in cats, and the solution is not possible. So what we need to do from the medical management perspective is either start diuresis and usually, we need to, we could attempt it between 1 and 4 days, either with fluids or with the junction of monitor, or we can try to.
Relax the urethral muscles. We can use calcium channel blockers, glucagon, amitriptyline. However, none of them has been widely studied or if available, you can try the extra, extra corporeal shockwave.
I think the main decision at this point is try to avoid surgery versus try to avoid a kidney damage and it can be very difficult to decide and I'm gonna show you how things have changed, with, with, with the ears. So for example, for the medical management perspective, what, what I would like to highlight is the difference in the, in the survival statistics. So in one or two years, we're about 66% with medical management, whereas with surgical management, we're about 90%.
So throughout the years, the with the approach has changed. So before year 2000, we used to suggest up to 4 days of medical management. After 2000 we suggested no more than 2 days.
My feeling is nowadays we are much more proactive, so we find an obstruction and if it's not responding the first night during the 1st 24 hours, we take them to to surgery. Successful of medical management, if you have, if you want to have a number in mind, it should be 10%, roughly. This is, one of the, most common feature that we can see in, in Celsi during investigation, which is the big kidney, little kidney scenario.
So we have this renal asymmetry, which usually is in young young cats, pure breeds with high level of creatinine, but they are relatively asymptomatic. And literally what we find in surgery is one of the, kidney is incredibly small, like 1 centimetre all around, literally a peanut, and the other one is very dilating and you can see that he's suffering and that is our target mainly because we want to try to preserve the kidney as much as possible. What are the surgical option?
So, surgical option depends on the patients, mainly, cats or, dogs, and we can see how the decision's gonna change. The surgeons, the type of training, the expertise, the preferences that can change, and the equipment. So some surgeries, so some specific procedure that we're gonna see require a specific type of equipment.
Obviously, if we don't have the, the, that equipment, we cannot do the sort of surgery we need to decide for something else. So on the right hand side, I proportionally draw these these ureters and how they change between a human being, a dog and a cat. And you can see how difficult will be, what, how small the, the ureter of a cat is compared to a human.
So when we talk about traditional surgeries, or traditional procedures, and we have few options. Obviously, ureteral nephrectomy, so we're gonna remove the kidneys and the associated ureter. Obviously, we need to make, make a, we need to be extremely sure that the other kidney will be able to, to support the, the entire body.
Otherwise that would not be possible. Resection and ostomosis in case of neoplasia, a stricture, maybe a calculi, maybe a necrotic part of the ureter. Then we could have a reimplantation on the ureter, specifically if our disease ureter, like a stricture or stone is on in a distal position that we can reastomo the ureter, to the apex, to the bladder, or we can do a ureterotomy, so little incision of the ureter.
We're gonna remove the stone and we can suture, the ureter. But surgery, as we said, is extremely challenging because of the size. You can see here on the left hand side, there is literally a suture material confirming the patency of of the ureter.
On the right hand side, you can see an intraoperative picture with the, ureter extremely dilated and extent inside. In this case, obviously with a ureterotomy and remove a stone. The suturing becomes slightly easier because it's such a dilated ureter that makes things, easier.
But if we need to deal with the normal ureter, that will be extremely, difficult. I hate to say we're not gonna discuss, traditional surgery today, but, I like to leave a stent inside when I do some sort of surgery, to the ureter just to protect my, surgical side. So, we need something else, and what we need is an intervention radiology procedure, is what we use nowadays.
And we have two big options for ureters. One is the subcutaneous urethral bypass that you can see on top, and or urethral stains, which you can see at the, at the bottom. So subcutaneous urethral bypass or simply sub, there's been a few designs throughout the years.
I'm gonna leave you here the two, the last two designs, so the sub 2.0 and the sub 3.0.
I feel that the 2.0 is still available, and the 3.0 is the one that is available now or suggested.
It's a bit of a different design. I'm gonna talk mainly, on the sub 2.0 because I think it's more obvious.
So the difference between the two is the 3.0, we have an internal Y connector between the nephrostomy tube and a cystostomy tube, and it takes, to the swirl port. But I think talking about the sub 2.0 will be easier, is more obvious compared to the 3.
So the sub has three parts, basically. And you can see here, this is a 2.0 option.
We have a nephrostomy tube that we're gonna place within the renal pelvis. We have the shunting port, which is gonna sit on the subcutaneous tissue, so outside the body wall. And then we have the cystostomy tube that is gonna reconnect the, so the, the renal pelvis to the port and to the port into the urinary bladder.
Here, I'm gonna leave you just for, for interest. You have, the, so the sub is produced by NorfolkE products. In the two links, you can find basically the surgical guide and a full video of the surgery if you are interested.
You have two surgical guides, one for the 2.0, 1 for the 3.0, which are extremely helpful.
So, this is a, a, a quick video. Of the placement of the nephrostomy tube. So, the idea is basically we're gonna stick a needle inside the renal pelvis.
We inject some contrast. We identify if you are in, in the correct position. We have identify the, the dilation of the renal pelvis.
When we are in a good position, we're gonna advance a guide wire, which is very soft and it tend to curl into the, the renal pelvis or sometimes it go down into the ureter, which is absolutely fine. When we are in a good position and enough guide wire is into the renal pelvis, we remove the catheter, so we're gonna have only the guide who are left, and we're gonna start advancing the nephrostomy tube into the renal pelvis. The nephrostomy tube is a black marker that you can see coming up in a second, and the, the black marker has to be inside the renal pelvis to make sure that all the the fenestrations are within the renal pelvis.
And they, we, what we need to have is a nice curl of the pig tail into the, the renal pelvis. It's actually not extremely important, but it's nice to have. It doesn't need to be too open.
It doesn't need to be too tight because otherwise we can obstruct. The, the nephrostomy tube. So you can see the black marker into the renal pelvis.
On the left hand side, we can see the advancement of the dacron cuff, which is the one that's gonna be glued to the to the renal capsule. And where we're in a correct position. We're gonna inject some more contrast.
We see the nice curvature of the pigtail inside the, the renal pelvis. And, on the left-hand side, you will see the, they're glueing the dacron cuff to the renal, capsule and that it's gonna stay, they locked in place. So here are the three parts of the surgeries.
Well, actually, only 2. You can see on the left, top left, you can see the placement of the nephrostomy tube into the, urinary bladder. It's exactly the same as you see before.
The only difference is on top of the glue. You, we ask. Place 4 sutures to lock it in place.
On the top right, you can see the placement of the glue on, around the cystostomy tube. And on the bottom picture you see actually the nephrostomy tube and the cystostomy tube placed. And those tubes need to be connected to the port.
And that's the port. So this is a, a 2.0.
So both tubes need to come out through the body wall, giving, avoid any kinks, so giving a nice curve, to the system. And we have this port in the subcutaneous tissue, so outside of the, the abdominal body wall and sutured in place with some non-absorbable material. Before finishing, obviously, we need to make sure, that the system is nicely placed, so we don't want any kinks.
So we have this, all these tubes, they have to have big, curves without kinking. you can see the ports highlighted very well. And, what we want to see as well is, .
No extravasation of contrast and obviously the contrast goes into the bladder and into the kidney. This specifically was a post-operative picture. After a while, you can actually see that the ureter became patent with time, which actually is what we see in about 50% of the of the cases with time because the ureter has time to relax and, slowly push with the peristalsis, push the, the stones forward into the urinary bladder.
Post-op post-op management, it can, it can be demanding. So what we do in the, in the post-operative period is, placement of an old tube, nearly all our cats. Antibiosis, so antibiotics usually payoperatively, we don't continue after unless we, we have already evidence of a, a UTI.
And then, during the post-operative period, we tend to repeat to have serial ultrasound, to make sure that the system is, patent. We collect some urines for some bacteriology, and we tend to flush, the subsystem with some EDTA. Here you can see this flashing with bubbles, into the, into the urinary bladder, so we're making sure that the, the system is patent.
This is, Huber, so what is the port, and the port allows to use, or we, we must use only Huber needles to not damage the port. So, we have the skin and the port. We stick the needle inside down till we feel this.
Metal filling and then we can connect, or we can draw some urine and inject some tra DTA that has been seen to be beneficial for dissolution of mineralization or to avoid mineralization of the system and obstruction. And we tend to do this, I would say, we tend to see our cuts after 4 weeks. And then if everything goes OK, every 3 to 4 months for the first year, and I would say 4 to 6 months from the second year after.
So overall, he is a good system, so it definitely simplified the treatment of urethral obstruction in, in cats. It can be safely flushed to make sure that the system is still patent. Every now and then cats allowed to do flushing without a sedation, so totally awake.
It tends to be effective long term with the correct management. And obviously, we eliminate all the risk with all the traditional surgery and especially if the use of potentially nephrostomy tube, which they tend to be associated to higher risk of complications. The good thing of the sub is, in theory, we don't have any implant in cats close to the trigon.
This one could stimulate sterile, cystitis. So we are very far away from it, which is good. We basically achieved the compression theoretically in all the cases and also long term.
And we see that the creatinine level should reduce exponentially. Obvious depends if we have an a degree of chronic kidney disease or an underlying. So what we tend to do is we keep monitor the, the creatinity, it goes down and roughly reach a plateau.
And when you reach a plateau, that's probably, it won't change that much and we can quantify the degree of chronic kidney disease and, and change the management based on, on that. In terms of outcomes, there has been a few paper, . Let's say if we start from the top one, I, I just let you probably the last three, potentially the most interesting one.
The first one, which is what is basically described our experience, let's say it's coming from the, from the RBC. What we're seeing is minor complication where about 20%, major complication. Manageable where about 50% and there was a a significant association between the long term survival and the creatinine level at presentation.
So the lower the creatinine, the, the better the long term outcome would say. Usually, and this one was associated as well to 10% of mortality at the hospital. However, the majority of the complications were actually, manageable.
The, the second paper is just interesting because basically, there's a multicenter study which show, let's say, an unusual complication that we have seen in a couple of cases, well, which is a migration, mainly the nephrostomy tube into the abdomen and specifically into the, the intestine. So this is something that we need to be aware about it. And the last one.
Show a high proportion of cuts with the subs that show again sterile urinary tract signs. And that makes the differentiation between bacteria cystitis and subclinical bacteruria quite difficult, so they're still open up to more study based on, based on that. In dogs, we don't tend to use subs.
So, I, I would say subs is a gold standard in, in cats nowadays, but it's not in, in dogs. And but it can be used, and I will say the reason behind it is, well, we have something better. And the, the major risk is that the most common long term complication was actually the mineralization of the of the subs that was happening much quicker compared in in cats.
So if for example in cats the suggestion was to flush the system every 4 to 6 months in in dogs here we're suggesting to basically to flush much more often nearly on a monthly basis, which it can become difficult to to manage even from the, from the owner perspective. Overall, the sub is not the best solution ever, but it is the best solution that we have right now, especially for cats. We can use subs for neoplasia.
Obviously, we need to consider it's quite a big surgery, as you can imagine, so we need to consider the media survival time and the potential complication to, the specific, patient with the result of the surgery. It would be an intense postoperative management, but it can still be effectively as a mid long term solution, but we need obviously to discuss to the owner the fact that this will be a palliative procedure, but we have done it and effectively, it's a good palliative results. Here, we're gonna move into urethral stents.
So, I will say that the sub is the gold standard for cats. Here we go that, the urethral stents is the gold standard for dogs. Stents are basically these, double pigtail, devices, that are placed through, the, the ureters basically.
So they bypassing the ureters but within, within the ureter itself. And we have four main aims. One is obviously to diver divert urine, so to bypass the obstruction.
And stimulate passive urethral dilation, and this will allow some stone to actually move distally and be eliminated through the, into the urinary bladder. It can facilitate or protect resection and anastomosis of the ureter or ureterotomy, which is something that I will always use on top of the traditional surgery and obviously they tend to prevent the nephid migration that can obstruct again, the ureter. The use of urethral stands for the treatment of both benign and malignant urethral obstruction has been described in several veterinary studies and the most commonly reported indication, for stent placement, has been, benign obstruction with calculi or striction.
It's interesting to know that for example, in humans, they have up to 80% of morbidities, where it's actually in in dogs and cats is, is much better, well, I would say in dogs is much. better tolerated compared to, to humans. So they can, they can stay there for a longer period of time.
And we have different modality of, placement that percutaneously, endoscopically, surgically assisted. So we're gonna see all the different options. First of all, the preparation, obviously, to place this stents based on, on the modality that you choose, you need to have some specific equipment.
Endoscopy, fluoroscopy. Obviously, an operating room and you need to maintain an aseptic technique throughout the the procedure because otherwise, you can have surgical infection or a UTI. Position, usually we have the, the dogs on the edge of the table, especially if we need to use an endoscopy.
So we have, you need to have enough space, for someone to, use the endoscope, for the floral and obviously for the surgeons if you decide to place it, surgically. So edge of the table, so the tail is completely down. It needs, it needs to be clipped and aesthetically prepared for like for a midline ceotomy.
Even if you decide to do endoscopically, we want to be ready just in case something doesn't go according with the plan and we need to convert to to surgery or we have a complication and we need to open the, the abdomen. And usually we need two operators, one on the endoscope and one on looking at the fluoroscope. We have different type of placements, antegrade, so we have kidney to urinary bladder.
This can be, well, surgically or percutaneously. We have retrograde, so from the urethra, to the kidneys. Again, percutaneous technique, usually, on the ultrasound guidance to visualise the renal pelvis and, and flu fluoroscopic guidance to see where the stent is, going and to confirm the correct position.
Or we have surgically, surgically is, it can be used for dogs, cats, we can use retrograde, so, through a cystoomy or antegrade through the, the, the kidney, basically. So here an example, yes, either the surgically integrate or percutaneously integrate. That's the same technique pretty much.
So we get a needle into the renal pelvis. We drive down a guide wire, along the ureter, so bypassing the obstruction, and we curl it into the urinary blood. And when we are in the correct position and we're happy we drive our ureter down again we bypassing the ureters as you can see exactly as in the sub we normally tend to have these black markers that they confirm in this case of the fenestration and the length of the of the pigtail so they needs to be inside the urinary bladder and when we are.
Happy with the position, we retrieve the, the guide. The pig tail is gonna form. Usually there is a lot of stent available remaining into the urinary bladder.
We continue to remove all the guide and when we are at the level of the renal pelvis, we have obviously the forming of the pigtail also in the renal pelvis. Here, an example on a surgically placed stent. In that case, you can see a cystotomy, on the, on the right hand side of the picture.
And, but we started inserting the stent through the renal pelvis, as you can see on the, on the left hand side. And you see basically the correct placement that you start from the kidney and the stent comes out through the ureter into the urinary bladder. You can see the guide wire on the left hand side.
And if we retrieve the guide wire, the pig will form inside the urinary bladder and we just need to push the last bit of stent, through the, kidney. Here's another videos. There is an endoscopic placement, basically, it's a retro retrograde technique.
So with the endoscopic go at the level of the urethral opening, exactly the same. It's always the same story in interventional ideology guidewire first, very soft. They bypass the obstruction.
They reach the, the renal pelvis, then they curl into the renal pelvis. At this stage, we should use a catheter first. In this video, they use directly the, well, they use a catheter first and, and then the stent.
We tend to use the catheter just to highlight the position. So we inject some contrast and we make sure the, the renal pelvis is dilated. We have enough guidear into the renal pelvis, and then we, we draw the catheter to make sure we are bypassing the, the obstruction and we can see all the contrast coming down.
When we are in the correct position, obviously, in this case, we're gonna remove the guide one and advancing the catheter into the, sorry, the stent into the catheter. You will see that the, the pigtail catheter is gonna simply curl into the renal pelvis this time. And in this case, we just need to withdraw the catheter.
You can see all the, the stent coming out. So there is a pig tail. We're in a very good position, so we, we draw the catheter, so we free the stent.
We bypass the the obstruction at this level. And when we are in the urinary bladder, we just need to remove the catheter and the pigtail will form. Here, one of our patients, so from the left hand side, as you can see, we basically catheterize the, the ureter and we inject some contrast up to the renal pelvis.
So we have the full length of the, of the, of the ureter highlighted. On the middle picture, you can see. The guide wire, into the, into the renal pelvis and along the, the ureter on the picture on the right hand side, we have the catheter.
So, the catheter, we will inject some more contrast and make sure again, we are in the correct, position and make sure that we know where the obstruction is. When we are happy, we start, . Deploying the, the system.
So, on the left-hand side, you can see catheterization and contrast into the ureter and into the, the renal pelvis. And on the left-hand side, you can see the placement of the stent, and obviously, we are deploying the last bit of the stent into the, urinary bladder. So it's a good position and that's it and basically in this case, we avoid a proper surgical procedure effectively.
Outcomes, overall we have some short term outcomes which are good. Obviously we see a decrease of urea creatinine level after one day and resolution of azotemia because we bypassed the obstruction effectively on the long term, the only thing that has been reported is this very high percentage. Of the suria, especially in cuts.
So, and we call it sterile cystitis because effectively we don't have an underlying UTI and the suspicious was that because of the anatomical position of the urethral opening cuts, so very distant, nearly, so the level of the trigon. Maybe we suspect there was a constant irritation. So that's why, it is a, is a major component in cuts for deciding to place a sub instead of a, a stand.
Overall stent exchanges or replacing was up to nearly 30%, so still quite high, and the downside is exactly the lower urinary tract signs refractory to medical management, making, making the management effectively difficult again, especially in, in cats. They're definitely better tolerated in. In dogs, dogs, we tend to remove them at some point, especially when we use them to protect the surgical site and ureterotomy or a resection ostomosis, we tend to remove them, through a cystoscopy after 4 weeks, 6 weeks, something like this that we make sure that the ureter has definitely healed.
So, if we divided in different species in dogs, low mortality rate, highly successful complication definitely lower in dogs compared to, to cats, we still have a decent amount of risk of UTI and risk of. Sending pyelonephritis because effectively the stent maintained the ureter and basically the connection between the ladder and the kidney constantly open and then other possible complication reported we have occlusion, migration of the stent, and obviously requiring a stent exchange. In cuts again, still successful because obviously we want to release the obstruction.
So from this perspective it's still successful however, and obviously we, we are avoid any traditional surgery in cats which is great. However, it is still associated to high long term complication, the suria, tendoclusion, migration more than than dogs. Stents is being useful also for malignancy.
This is one of our cases, it was a a Westie, a 13 years old westie with the transitional cell carcinoma. Unfortunately, funny enough, at least the, the transition of a carcinoma was growing in a way that it wasn't really obstructing the, the urethra that much, but it was obstructing the urethral opening. So being a dogs, we decide to, to place a stent, so you, you could see basically, this CT scan, you can see the stent inside this .
Very bright white structure with a curve that was the stent. It was bypassing the, the obstruction, obviously it's palliative but that means that basically the tumour continued to grow, but at least it's growing around the stent and the stent should should have enough fenestration to buy more time. Again, we're talking about palliative procedure and in this case, the dog reacted very well and the, the stent stayed there for basically the rest of its life.
Yeah, we're gonna leave you some nice resources. The first one is the, the, the classic consensus, the SCVIM consensus on the treatment of urin in dogs and cats and, that is the part for the ureters and the part of the urethra. I find it incredibly helpful.
So especially when you are deciding what is the best thing to do, going back to the consensus, I think it's quite helpful. And then, we have a nice review, from Dana Clark, regarding the medical and the surgical management of urethral obstruction, in dogs and cats is very helpful resources. Now we're gonna move to the urethra and the main two focus or topics will be urethrolithiasis and neoplasia.
That's because we have some new way to deal with this sort of pathologies. So, specifically for eurolithiasis, why we want to avoid traditional surgery, either cystoomy plus or minus erythrotomy. Well, in theory, even if it sounds very high, if you look at the literature, incomplete removal through a normal traditional surgery has been report up to 20%.
With 10% of recurrence due to the suture induced stone formations and due to the cystoomy basically. We still have a quite a decent amount of complication, 40 to 50%, either minor minor or a major complication. Obviously, we have a longer hospitalisation if we compare it to the new minimally invasive technique, and there is a risk of stenosis every time that we do a a urethrotomy for scar formation.
So, first of all, if we can avoid surgery, I think we should, but obviously we need to be aware of the type of stones. So we know that strobite, for example, and urates respond very well to medical dissolution and in theory, unless we have an active obstruction. We should probably not go, go for surgery and attend medical management and proactive monitoring of these patients.
16, 50% of them, they respond to medical management. 50%, they require surgical management. Other, .
Euroliths that they don't respond to medical dissolution will be calcium oxalate, the other 50% of the cysteine. And then we go for surgery, as we said, any, every time that we have an actual obstruction, so independently of the type of stone because obviously that becomes an emergency or if we have a current UTIs, that we are not able to get on top of it and that is we think that the nidus is actually the, stones. So what we need to do after either medical dissolution or also after surgery, other traditional or minimum invasive is always proactively monitor this patient to try to prevent recurrences.
So, what are the new minimally invasive options, shock wave, lithotripsy, laparoscopic assisted cystotomy. Now it's a, a bit out of fashion, to be honest, because, we nowadays, we do the percutaneous cystoliotomy, which is the main focus on the talk. We can do laser lithotripsy.
This is something that we still do, so we go for a laser. With the laser very close to the stone, and we try to break the stone in smaller, fragments and we can potentially leave it and, they're gonna be excreted through the urine, or we can associate the laser lithotripsy with the APCCL, so percutaneously soliotomy. We could have a cystoscopic guided basket retrieval.
So through the, the, the urethra, if the stone is small enough to pass through the urethra and not damage the urethra itself, or in some cases if they are very, very small calculi avoiding euro hydro pollution. So the case selection is important. Obviously, if you are dealing with female dogs and cats, we can do, transurethral cystoscopy, making sure those stones, they easily pass through the urethra or we can do the lays the cystootomy.
Or the PCCL in male dogs and cats do the anatomical conformation, we can only do a lapacystic cystoomy or a PCCL and as I said, nowadays our preference is PCCL over the layed cystoomy. If we have laser lithotripsy, we can definitely use it in combination to, fragment the larger calculi. The main contraindication on minimally invasive techniques are mainly very large stone.
They require a big incision. Or if we have many, many stones, the, the PCCL becomes tedious and very long anaesthetic, so it's not really worth it. So this is a percutaneousytolithotomy, a nice picture that basically we go through, the, the abdominal wall and, we grab the bladder and we go also through the bladder with the, with the cannula.
And through the cannula, we can use an endoscope to have a look inside, or we can have an endoscope down the urethra. We can use some basket or some graspers forceps to remove all the stones. The equipment for a PCCL, I will say he is a little demanding, so we need to have a 5 millimetres laparoscopic tri the cannula, open surgical kit.
We need an endoscope. Usually, we use a 2.7 millimetres, 30 degree rigid endoscope.
We need to have a series of basket or graspers for stone removal and then a urinary catheter to flush continuously the urethra and the the bladder during the procedure. So, we start the, is, is effectively, it's still a surgical procedure, so we need to have the, our patient dorsal recumbpancy. We need to have a urinary catheter through the urethra and then make sure the urethra remain patent, so there are no stones going back into the, the urethra.
And again, we can flush fluids that helps to move the stones and in theory, coming out. From the, from the cannula. And then we do a very mini laparotomy.
Literally 1.5 centimetre incision on the midline and probably about 1 centimetre incision in the, in the abdomen. We grab the, urinary bladder, so we need to be quite precise in our little laparotomy, that should be at the level of the apex of the bladder.
That comes a bit with experience. We place a stay suture at the apex of the bladder, so a full thickness. Bite on the apex of the bladder and we bring the bladder toward the the abdominal wall.
We do a simple and stabbing incision with an 11 blade and we threaded the cannula inside. So now we have a full access to the lower urinary tract with the . A catheter into the urethra and the cannula through the abdominal wall into the urinary bladder.
So this is what we have basically. So we pack all the area, making sure we maintain well, clearly an aseptic technique, and even if we have some, we protect the rest of the, the abdomen for, an extra position of, of urine. And through this cannula, we're gonna insert a rigid endoscope.
We have a look around the bladder and the proximal urethra. Then we can remove it, and we start with some flashing and already with the flashing through the urethra, we're gonna push the Stones back into the into the cannula. The cannula is quite overall, big, so we create a nice flow and many stones will already come out.
The one left inside, we're gonna go in there with a basket or a grasper and we go and get them. So this is like a an, an example, one that we can a couple of stones that we grab with some graspers. Obviously, that's why I was saying that if you have multiple or many, many urethral leaves, maybe it's not worth it because.
Be a very tedious and long procedure, but if you have a decent number, and you can get away with, with this procedure, it will be better for you because it will be much quicker and the hospitalisation, the recovery period will be incredibly quicker, for, for your patient as well. Here we use some graspers. You can easily use baskets to get more stones at the same time.
Aftercare is actually quite simple. So before, finishing the surgery, we're gonna try to evaluate the entire urethra. So the best case scenario is also to have, in case we're dealing with the male, to have a flexible urethroscope where you can evaluate the entire length of the urethra to make sure there are no stones left.
The closure is a routine. Usually, we use 12, suture on the urinary bladder wall or a simple a cruciate a single cruciate mattress and literally 2 or 3 sutures on the . Abdominal wall, the patient can go home the day after and this is, so this procedure is being associated with only 4% risk of incomplete stone removal.
If we compare it to a traditional cystoomy, it is up to 2, to up to 20. So, in theory, if we can use this procedure, it will be way better than a traditional cystotomy. It's be more demanding in terms of Skills and in terms of equipment for sure, it, it get, we need to get used to it and I'm sure you will find that the first couple of procedures that you do, they will be much longer than the traditional surgery.
You just need to persevere with it. On the postoperative care, you just need to, the classic monitoring, so pain post-op, making sure they're urinating well. We could have some immaturia, nothing different from, from usual.
Make sure they're well covered even if they don't really need, a big amount of analgesia, bastard cover just in case and a restriction for one or two, weeks. This is a paper that, I've done recently, at the, at the RBC and what I've done differently, this was dogs with traditional cystotomy, but they with the use of a flexible urethroscope, to make sure that the urethra was patent. So rather than do the classic contrast study or the graphic contrast.
Which takes time for us, so we need to move the dog, outside of our operating room, take the X-rays, and so on. I normally really like to use this sterile, endoscope, and we can literally, double check the entire, urethra. In this case, this was a, a very big dog, and I was checking the urethra with a catheter and I could not feel any obstruction.
But actually, when I went in there with the urethroscope, you can actually see a stone partially obstructing the, the urethra. And thankfully, we've seen it and we, removed it with a pair of graspers, as you can see on the, on the right-hand side. Next, next step we'll be talking about neoplasia.
Neoplasia of the urethra is very difficult to deal with. On the left hand side on the video, you see the classic TCC affecting the urethra, very severe TCC you can see this. Fluffy, tissue all white that is kind of classic of, TCC.
Obviously, if you, if you see this situation, you should take biopsies and, and luckily, so not likely, and very often we're dealing with the obstruction due to this situation. What are these options, our options, not many. So rejection astomosis, unless it's very, very localised, which is not the usual case, this is not feasible.
We could place a cystostomy tube as a palliative, procedure that will work well, very demanding, I would say from, for the owner, or we can place a urethral stent and it's actually what I'm gonna talk about, right now, and it's a minimally invasive sort of procedure, very simple and effective. So, utter stent is definitely an alternative to traditional methods of urinary diversion. We need to select the patient and I think also the owner, I would say, in terms of imaging, we require fluoroscopic and potentially endoscopic visualisation.
And we tend to use a retrograde approach. However, a surgical approach, so an anti-grade surgical approach is definitely possible. So, the patient selection needs to be based on what the clinical history, the clinical examination.
In all of these cases, we should do a rectal exam and a vaginal exam. Obviously, . It placement of the stent, we need to make sure that with the stent we are bypassing the entire obstruction.
So a TCC for example, that is affecting the entire urethra ideally, is not ideal because we, we, we should bypass the entire urethra with the stent so we make for sure the dog completely incontinent. These are few sort of investigation that we should do before going for a stents or radiographs, or fluoroscopy, ultrasound, urethral cystoscopy, biopsy to make sure that we know what we're dealing with in a positive contrast, urethrocystography. We can use them for benign, I guess, urethral obstruction, for neoplastic, so malignancy, or for in case of an extra luminal urethral compression.
Sometimes it's very difficult to differentiate between obstruction and inflammation. That's why potentially doing biopsy before it will be an important procedure to do. So patient selection, we need to remember that effectively, only 10% of dogs with lower urinary tract neoplasia will develop urinary obstructions.
Probably those are our target for this procedure. And even in dogs, so we need to be very careful in during our clinical exam and the clinical history taking about the question they were asking the owner. So we need to focus on as a failure to empty the bladder of a poor urinary stream despite the fact they are urinating, it may indicate a partial obstruction.
So those patients are still suffering or there's a big discomfort during the urination. So in these cases, we can consider placing a stent. So, in terms of patient preparation, it can be used in dogs and in cats.
In male cats, we require a proper surgical procedure because we can place them in a normal grade axis. So from the urinary bladder down to the, to the urethra. Obviously, they're gonna be anaesthetized, always better to give per operative, antibiotics.
We need to have them in lateral recumbency and we're gonna place the stent under fluoroscopic guidance. Even though it's not a surgical procedure itself, we need to maintain an aseptic technique as in case it was exactly as it was for a a surgical procedure. And in terms of instrumentation, obviously, we need a fluoroscopy.
We need a, a guide wire. We need a sort of vascular sheets to, to help the, with the deployment of the system. We need a dilator.
A marker catheter to decide the diameter and the length of the, of the stent and a catheter for our contrastudy. The stent that we're gonna use is a laser cut, self-expanding metallic stands, so they are made of ninol. There is no foreshortening.
So that means that if we, if you want to place a 60 millimetre stent. It would be 60 millimetre either if it's fully expanded, fully open, or, or not. That's very different from a, for example, a tracheal stent, which they are for shortening.
So if they're not fully expanded, they are longer. And what we, we need to pay attention of is that the length of the diameter of the stent, should be in theory, 1 centimetre cranial to the obstruction and 1 centimetre coda to the obstruction. And in terms of diameter, we should go between 0 to 20% bigger than diameter, the normal diameter of the urethra.
If, for example, we are struggling with the full deployment and the the stent doesn't open properly, we can use a balloon dilation. So get inside the stent with the balloon and try to to expand it. Usually, we can also use a covert stent.
Stan selection here, I'm gonna leave you like the the scale. So basically we we can increase every 2 millimetres in diameter, and, and then there are different lengths. And this, you can, on the bottom picture you can see actually the length of the diameter with the two markers, black markers that they indicate the, the starting point and the endpoint of the diameter in the deployment system.
So, here is just a quick video from the AMC here's a contrast study. We can see an obstruction at the level of the prostate basically. We have a, a big guide wire, .
Occurred into the bladder so we have full control of the urinary lower urinary tract so bypassing the the obstruction. So what we, we can do is basically we can do a urethral cystoscopy if needed unless we know already what we are dealing with. We need to advance the guide.
Where through the urethra into the, into the bladder with the catheter, we inject the contrast to highlight the full, urethra and also to take measurement because obviously injecting contrast, we are dilating the, the urethra. And this is the measurements that we do. So we use a marker catheter in the colon rectum, as you can see on top.
And we know that from one marker to the other marker is exactly 1 centimetre. Then we're gonna do our contrast study and you can see the big line indicates the length of the obstruction. So we calculate the, the length and we add 1 centimetre on each side.
And then, as you can see, the, the letter B indicates a normal maximal dilation of a normal urethra. So that is caudal to the obstruction. We want to dilate the urethra with our contrast study.
We take the measurement and either that is. Gonna be the size of our stent or we can increase up to 20% to the measurement. And this obviously we need to do a proportion from the 1 centimetre and just to calculate our B basically.
So the diameter of a normal urethra. And I, I left you the proportion to do in case for the calculation. Here's the deployment of the system, always from the AMC and you can see the stent, so you see the two black markers indicate the start and the end of the, of the of the stent.
Often, these tumour, they tend to be at the level of the trigon, right? So they are actually inside the urinary bladder. What we tend to do in this situation is start opening the stent inside the bladder, so the level of the trigon.
So we wanna open the stent and there's the deployment system that does that for us, we, we basically remove the sheets that is covering the, the stent and the stents tend to tend to open. And then if you're happy with the position, we continue to open the stent bypassing the, the entire obstruction. So here you can see on the left side is, is, start opening and we are right in the, in the trigon, and sometimes we can pull it as well to make sure that the, the stent is fully engaged, to the, to the tumour or to the, to the trigon, and then we continue to open up bypassing, the entire obstruction.
At the end of the procedure, we need to repeat the contrast study to actually making sure we bypass completely the obstruction. The idea to open the stent into the bladder is simply, let's say to buy more time. So this, remember that this is a palliative procedure.
So opening the stent into the bladder, that means that we give more time because the tumour will start growing. Around the stain, but awfully, we maintain patency for a longer period. So in theory there's a normal procedure that we do.
We open into the bladder and then we're and we continue to open bypassing the obstruction. Post-deployment, again, pretty straightforward, so we can repeat the urethrocystography to making sure we're happy with the, with the obs so with the release of obstruction. We need to make sure that there is a, a con, the contrast flow easily, to be honest in both directions, so we also need to, we can gently squeeze the bladder to making sure the dog will be able to, to urinate.
There's no need of urinary cat. Post-op, we need minor monitoring post-op, so just making sure they're able to, to urinate. And from that point of view, monitor the, the urinary incontinence and obviously pain relief usually are not really needed.
In terms of complication and outcome, I think we need to remind ourselves and especially the owners that this is still a palliative procedure, so potentially an expensive a palliative procedure. However, we could achieve a good quality of life for our patients. The, I, I would say probably the, the main point to discuss would be the risk of urinary incontinence after the placement of, of the stent.
There is some sort of medical management that we can attempt, but obviously I would, I would probably say that 25% of dogs that would place stents are at risk of urine incontinence. I would say a big problem is how incontinent are they? And what I tend to say to the owner is 25% of that 25% that are incontinence will be severely incontinent.
There is no risk factor, there is no, it's not predictable on which will be more incontinent than, than the other, but it, it can, it can be a problem. I guess some degree of stranguria hematuria is possible maybe to start with that and we can use some anti-inflammatory, I guess, but tumour regrow, overgrowth is less than 10, 10%. So overall, for such a terrible disease, we is, is a good palliative procedure in, in my opinion, bear in mind the risk of complications.
And this is a couple of resources, as, as usual, the ACBIM consensus for the ely treatment and prevention, mainly on the, on the urethra, side bladder and urethra would say, so you lower urinary tract and, and on at the bottom, you can see the Minnesota Uly centre. This is my way to go every time and managing these patients and the resources you. You can find literally every sort of treatment and monitoring suggested for that specific, type of calculi and dogs and cats.
And obviously they're gonna tell you what sort of diet, what sort of monitoring, what medication they should have, and I found it incredibly helpful and I know that is the probably the management postop is the most frustrating part for these cases. OK, we reached the point of this, so the end of this, webinar. I really hope that you, you enjoyed it.
Thank you again, the webinar vet. I'm gonna just let you know that I'm part of Velit, and it's mainly a website on veterinary literature, and, if you subscribe to the surgery newsletter, you're gonna receive some abstract every couple of months, the apps that I selected and I comment on it and it's quite fun and interesting. OK.
If you have any questions, feel free to email me and we can have a chat, OK? Take care and bye-bye.