Welcome everyone to today's webinar, which will be concentrating on rodents as surgical patients and in the immediate post-operative care. My name is Elizabeth Manchinelli, and I'm a European diplomat in zoological medicine, a specialty small mammal medicine and surgery, and I currently work for Valley Exotics at Valley Veterinary Hospital in Cardiff. Now rodents have become a very popular pets over the last decades and are nowadays very commonly seen as patients both from a medical and a surgical point of view.

But often the lack of familiarity with these pieces can complicate and can make their appropriate care a bit more challenging. During the course of this webinar, we'll try and discuss how to achieve more appropriate patient and equipment preparation prior to surgery, how to approach the rodents from a surgical perspective, and to recognise the importance of adequate post-surgical care. This is my disclaimer.

More specifically, the learning objectives of this talk are to learn how to assess the suitability of a patient for anaesthesia in surgery, to discuss how to approach common surgical procedure in several rodent species or more common rodent species, and then also will learn how to adequately care for a patient pre and post surgery. Small mammals are different compared to more traditional companion species such as dogs and cats. There are several reasons, but just to summarise a few of them, please consider first of all, their small size.

Obviously we are talking about rodent species which are commonly seen in private practise, starting from guinea pigs, which may be ranging in size from 5 to 800 grammes to 1 kilo.5k sometimes, and then chinchillas, but also smaller rodents. Species such as rats, gerbils, mice, hamsters, and, and egos.

Now the small size may represent a challenge, especially if we are discussing about general anaesthesia and the surgery, the anatomy may cause some complications to the practitioner that is not familiar with these species. The smaller size also implies that the metabolic rate is much Higher compared to other species which may result in higher oxygen consumption rate in complications occurring faster as opposed to dogs and cats, for example, and may also result in drugs having different pharmacokinetic or pharmacodynamic properties compared to dogs and cats, for example. So these are all factors that need to be taken into consideration when dealing with.

Smaller species or small mammals as opposed to dogs and cats. Rodents are also prey species. They tend to mask clinical signs of disease until they can't cope with the situation anymore, and this may pose a problem because many owners are not able to identify early signs of disease.

Therefore, the animal is often presented as an emergency when in actual fact the problem had been going on for some time. Stress may impact on these species in a different way compared to dogs and cats. They are highly stressed, they can, the pain and the stress can impact quite significantly on the species as opposed to dogs and cats, and this is also something that needs to be taken into consideration.

And also never underestimated the emotional attachment that many owners have for these smaller species, even if they are not dogs and cats, many owners are particularly dedicated to, to the rodents and therefore are expecting high standard of care for their pets. Now when discussing about general anaesthesia and surgery, there are important considerations to make. Now the husbandry is particularly important for all these species.

Many of these rodents are often neglected. They are often kept in very small enclosures with inappropriate. You know, conditions, and this may impact quite significantly on their health as well.

That's why when or even before a physical examination is performed, it is of utmost important to discuss details of the husband, including the type of enclosures the animals are kept, how the This enclosure is organised from simple aspects such as the bedding to the diet to the companions that are present within the same enclosure. You can see how different it can be the life of a pet kept in the first enclosure as opposed to something that is kept in this type of more stimulating environment. A physical examination is also very important, as we mentioned, the rodents are prey species.

They tend to disguise signs of disease until the very end when they can't cope with the disease state anymore. The physical examination may help the clinician identify objective signs. Objective clinical signs which may be an indication of an underlying disease state which may further complicate the general anaesthetic and or the surgical procedure that is going to be performed.

It is important to perform a complete physical examination or as much as possible depending on the species. Some of these. A smaller species may be more difficult to examine when they are conscious, and the approaches should be systematic from head to tail whichever way you prefer to do it so that any none of the organ system is is missed and everything is examined adequately.

So once the husbandry has been revised and please consider that there may be some variation in requirements depending on the species that we are taking into consideration, then a complete physical examination may be performed. Now it is important to remember very briefly that the handling of these species may need to be done quite carefully. You know, generally, guinea pigs and chinchillas are very easily handled.

They don't tend to bite, but smaller species may become a problem. For example, hamsters or mice, and, handling should be done safely both for the patient and for the handler for, you know, the vet that is examining the patient. In some cases, as you can see from this picture, a small towel or a piece of paper may be used to under the patient, more efficaciously and safely for the patient itself and allowing the veterinarian to perform a physical examination.

As mentioned earlier, there isn't a set way of performing a physical examination, but it is important to make sure that The respiration is assessed, the heart rate is examined as well, and the abdomen is palpating. The oral examination and teeth examination can be difficult, especially in smaller species and especially in the awake patients or wherever there is an indication for, you know, performing a general study to examine these teeth. So that is something that obviously can be discussed further with with the owner.

Now whenever possible, collecting a blood sample prior to a general anaesthetic and a surgical procedure and in order to evaluate the suitability of the patient to undergo that specific procedure would be of utmost importance. However, sadly, in the majority of cases this is not routinely performed in. Mammals as it is in other more common companion species such as dogs and cats.

One of the main disadvantages of collecting a blood sample in this species is also the fact that in the majority of cases a small general anaesthetic or short, brief, general anaesthetic or sedation are required in order to collect the blood sample as well. Whenever possible and whenever the block collection is actually performed, always remember that the block volume in this species is generally between 5.5 to 8% of the body weight of the patient, and that 10% of this blood volume or 1% of the body weight can be safely collected in one single blood draw.

Obviously, in case of illness. Whenever there is an evident or a suspected underlying problem, the amount should be reduced to at least 0.5%.

Always weigh the risks of performing a sedation or a general anaesthetic in an animal that is particularly sick versus the benefits of being able to collect that blood sample. Always remember also that. Vene puncture, depending obviously more or less on the ipuncture site as well, it can be particularly stressful because it does require, especially in smaller species, quite significant handling and therefore in the majority of cases, a sedation or general anaesthesia actually beneficial to reduce the struggling and that stress for the patient.

In many cases, especially where the the blood sample collected is very small, always prioritise the test that you think may be necessary in that specific case for that specific patient and consider the possibility of them collecting a second blood sample at a later stage once the patient has been stabilised to then have a more complete evaluation of the health status of the patient. Very briefly, there are different veny puncture sites that can be used. One of the largest vessels that can be accessed obviously under general an anaesthesia or sedation is the cranial vena cava.

You can see this performed in a rat in the picture, in a guinea pig, and in a gerbil. Now just. Very briefly, because it's one of the most common sites for blood collection in all rodent species.

Remember that there is a slight anatomical difference between guinea pig-like rodents such as guinea pigs, for example, and chinchillas and rat-like rodents. The first group of rodents lack a developed clavicle and therefore the mini puncture site is just a cranial to the. Rib between the first rib and the manubri, the needle can be inserted at about 45 degree angle, meaning aiming towards the opposite hind leg.

In the second group of rodents, so rat-like rodents which have a very well developed clavicle, then the vinyuncture site is between the first rib and the clavicle. Otherwise, we risk to a hip bone when inserting the needle. The needle is therefore inserted between the first rib and the clavicle again at about 45 degree angle, aiming towards the opposite hind leg.

Now, a blood sample as mentioned would give us very important information about the health status of the patient and provide us some more insight on what abnormalities may need to be corrected before a general anaesthetic and a surgical procedure are undergone. Whenever that is possible or even in absence of this information, it is always important to assess the suitability of a patient for the procedure and stabilise the patient. Before the procedure is undergone, this may require, for example, oxygen therapy for as long as possible for the patient to be stable enough to then undergo the general anaesthetic, provide warmth, fluids, and assist feeding.

We know that these guys have a very high metabolic rate, smaller glycogen reserves, and therefore are prone to hypoglycemia, especially when they've not been eating for some time. So it is important to correct any dehydration. And any anorexia that have been present for a certain period of time, especially because this may represent further risk factors during the general anaesthetic and the procedure.

We know that in other species, for example, the length of general anaesthetic and the the length of the procedure as well as other risk factors do impact significantly on the outcome of the procedure, and this is something that we definitely need to take into consideration in these smaller patients as well. Whenever possible, and this implies not just elective procedures, but obviously especially in an emergency situation, intravascular access which should always be considered in small animals as well. An intravenous or an intraosseous ca can be particularly helpful to deliver anaesthetic as well as emergency drugs.

Enable a more rapid response, especially in case of an emergency. It allows us to provide replacement fluids and is a very efficient route as opposed to the subcutaneous route, for example, and it also provides options for post anaesthetic nursing management. Now obviously you may struggle with smaller species, but it It's relatively easy to place a cephalic catheter, for example, in a guinea pig in a chinchilla.

In rats, you can place an intravenous catheter in the lateral tail vein as well. In an emergency situation, placing an intraosseous cadet can take as long as 10 seconds. So it's something that I would certainly advise you to practise.

Whenever possible on cadavers as well because it allows you to proceed with speed in case of an emergency. Always remember in cases where you are to place an intrascatter, this should be long enough to extend to at least 3 or 5 of the length of the medullary cavity of the bone that you're using. And that a wires should be commonly used to to reduce the potential for a bone cord to block the catheter.

In the majority of cases, they tend to use, depending on the size of the patient, a small hypodermic needle which is already pre-prepared and sterilised with a style in it, already ready in case of an emergency. So these hypodermic needles are prepared of different size already, so usually between 18 to 20. 5 code and the whitest are already pre-placed so usually stainless steel suture material, for example, and they are pre-sterilized for use of art intro card in place of an emergency.

The placement is very similar to that of other species, so, normal, normal grading search and as you were to place an interment. Requires a strict aseptic technique and should be performed obviously under general anaesthetic whenever possible or when the patient is collapsed, for example, under general anaesthetic because it's obviously a very painful procedure and a drop of lidocaine or vacaine can be injected through the skin into the periosteal bone before a placement. In all small mammal species, morbidity and mortality rate tend to increase as the extent and the length of the procedure increase.

And therefore it is extremely important to be able to plan in advance any surgical procedure and any anaesthetic procedure as much as possible. And this implies, for example, getting all the equipment the baby required for that specific procedure in advance, getting all the. Emergency drugs sorted in advance before the patient is actually anaesthetized so that the length of time that the patient is under general anaesthetic and undergoing surgery is reduced as much as possible.

In human medicine and in veterinary medicine, checklists have been implemented for a certain period of time because it has been shown that they tend to reduce the complication rates and even the death rates in in many situations. It is. Something that we do routinely use in our clinic as well, and checklists can be done very quickly and they don't have to be long but can include the simple things like checking of the anaesthetic machine, working out the volume of the emergency drugs, and even simple things as identification of the patient and intubation equipment.

And it is something that I would strongly advise you to consider in your practise as well. Other consideration prior to anaesthetizing and taking a patient to the surgical theatre is considered minimising the risk of hypothermia. The smaller, small mammals have a large body surface area to volume ratio, meaning that the heat loss occurs much rapidly as compared to dogs and cats, for example.

And because the majority of heat is lost by radiation, that this means that every effort should be made to minimise the the difference in temperature between the patient and the environment by increasing the environmental temperature and insulating the patient. Another important factor to consider is fasting because the rodents cannot vomit, then fasting is considered of little importance in these species and actually prolonged the fasting is contraindicated because they have a very high metabolic rate and a little hepatic glycogen storage, meaning that the risk of hypoglycemia is much higher in this species as compared to others. A short.

In some cases may be beneficial simply to reduce the amount of food in the mouth and always remember, for example, in hamsters to empty their cheek pouches prior to an anaesthetic and a surgical procedure, but ultimately fasting does not significantly reduce the gastrointestinal volume and may even induce or increase the risk of gastrointestinal complication in certain species. Another important consideration to make is the positioning, especially in those species which have a large gastrointestinal tract as you can see this guinea pig here which may potentially impair breathing during surgery, especially where the patient is in dorsum recumbency, then the. Position, as you can see in this guinea pig here on the left hand side of the screen.

So with the chest slightly raised compared to the abdomen, which can be simply done by rolling a towel and placing it under the chest, that can help preventing breathing impairment during the the procedure. Possible, intubation should be attempted in small mammals as well. However, this is certainly more challenging as opposed to the intubation, which is relatively straightforward in dogs and cats.

This is certainly not the case in any of the small mammals that we are taking into consideration. Now, in guinea pigs and chinchillas, I tend to prefer the use of an endoscope, ideally a 1.9 or a 2.7 millimetre scope, depending on which technique you are using, whether either over the endoscope or side by side.

Alternatively, a modified otoscope, so with the side removed can be used generally depending on the size of the patient and the size of the scope of 1.5 to 2.5 millimetre clear tube can be.

Used. Remember that chinchillas and guinea pigs have a palatal osteum which is diffusion between the base of the tongue, the palatal glossal arches, and the soft palate, which reduces further the diameter of the oral cavity and makes access to the the back of the mouth and the glot is a bit more challenging than than usual. Alternatively, a tracheostomy can be considered.

However, this is not something that I would routinely suggest. It's something that I have to do in a very few selected cases and in an emergency situation and it's done as in other species as well. For what concerns rats and small rodents again, this is something possible.

Intubation should be considered the mainstay of any general anaesthetic. However, this procedure is much more challenging in this species. An endoscope can be used side by side.

A 1 millimetre semi-flex. Scope is particularly useful but rather expensive for for this purpose and alternatively works and and intubation packs which are sort of inherited from the laboratory settings are also available for for this reason. This second part of the talk we'll have a more specific look into equipment that may be useful when performing surgeries in small mammals, in general in rodents in particular.

We'll have a look at different types of suture materials, patient into preparation prior to a surgery and patient monitoring during the procedure itself. Now when embarking on a surgical procedure on a smaller patient, the first choice to make is what type of instruments to use, and generally the choice is between ophthalmic instruments and microsurgical instrumentation. Here we have a microsurgical kit which generally Contains, as you can see, a needle holder, scissors generally with a round tip and with a pointed tip, and then obviously some hemostat and some forceps as opposed to ophthalmic instruments like the one that you see here.

Now I've tried both, but generally the difference is that oralic instruments are short with a flat. Finger grips. So I find them more difficult to manipulate and stabilise, especially when you are dealing with a very small patient compared to microsurgical instruments which are of standard length and have rounded grips.

So the microsurgical instruments only have miniaturised tips compared to the ophthalmic ones where the whole instrument is miniaturised. Always remember also to like you would do in a dog or a cat that you hold the instruments like you're holding a pen. Now some form of magnification and lighting is recommended when we are dealing with any sort of procedure in small mammals because of our inability to visualise very small structures which can limit significantly both dexterity and manipulations.

Now with magnification. Small amounts of a mortgage appear more significant and individual vessels are more easily identified for coagulation, which can minimise a mage, which is particularly important, obviously when we are dealing with very small patients. Focal lights also allow better visualisation of tissues, especially in a small body cavity.

Now, there are various types of lights with or without magnification loops which are available through different companies, so I'm not gonna discuss the specific models, but always remember that another good and inexpensive option is considered headband mounted LED lights, which I found particularly useful, especially for example, for dentals in very small patients. A piece of equipment that I consider a master product of whoever embarks in any sort of surgical procedure in a different mammalian exotic species is the Lone Star retractor. If you are not familiar with the Lone Star retractor system, this is comprised of a variety of self-retaining adjustable elastic spaces with tissue hooks at the end and a plastic frame which offers super.

Access and visualisation across a wide range of surgical applications. Abus lose the retractor in many abdominal surgeries, for example, consider the guinea pig, which is a particularly challenging species when we are dealing with any sort of abdominal procedure from space to other types of surgical surgical procedures to facial surgeries, and this is not just in small mammals or rodents. But in rabbits in particular as well.

So this is something that I do find particularly useful. I've used the lone star retractor as well to retrieve urethral stones in different exotic species as well. So definitely something that I would recommend to purchase.

Now, this is not something that has, that was born in the veterinary field that this sort of equipment is derived from the human field. It was used by gynaecologist and auto autoolaryngologists as well, so, quite a wide range of, procedures in the human field. Obviously in the human field that these are single-use retractors, and are sterile packaged, but obviously in the veterinary ward this can be reused and re-sterilized for you know, following up for subsequent procedures as well.

Now one of the things that we definitely need to worry about when performing surgery, especially in a smaller patient, is haemorrhage. Now the reported volume of small mammals is approximately 57 mL per kilo of body weight. A loss of 10 to 15% of the total blood volume is usually safe, but with a loss of 15 to 20% of the blood volume, most mammals will experience some hypovolemic shock and release a large amount of catecholamine.

So life threatening consequences generally occur with a loss of 20 to 30% of the total volume. Now, cotton tips are probably one of the most inexpensive and useful, commonly used hemostatic aids in exotic animal medicine, and they are particularly useful not just to absorb the fluid but also used for gentle. Tissue dissection and manipulation.

So they usually use the moistened for tissue dissection and for tissue manipulation, but they can be used to dry to absorb the fluid. It's very useful to know that the average cotton tipped applicator holds approximately 0.1 mL of blood when completely soaked.

So this means that we can sort of calculate. To the amount of blood loss that a mammal has gone through by counting the number of cotton tips that have been completely sold. So for example, for a loss of more than 5 cotton tip applicators full of blood in let's say in a 50 gramme mouse, this would be equivalent to a 20% of the blood volume and therefore potentially dangerous.

Alongside the cotton tips applicate on many other types of hemostatic aids that can be used as well that are obviously commercially available. I've just listed a few of them, but I'm pretty sure there are many others on the market. Laoip is a wet stable collagen hemostat.

Colagen leads to thrombocyte adhesion and to activation of cuagulation factor 12. Therefore, collagen is very effective in amosthesis. The main advantages are therefore, that it achieves emmostasis very swiftly and is completely absorbable and it can also be removed very easily.

Surgicel is another, hemostatic agent, is a blood clot inducing material made of an oxidised cellulose polymer. And it is used to control mainly post-surgical bleeding, can be left in C2 in some cases, but ideally should be removed once the most disease has been achieved. As I said, there are many other different typescalar gelatin sponges, so just be aware of what is available on the market and try different products to see the one that suits best to your needs.

Emostatic clips are also extremely useful in exotic animal medicine and available in various sizes with small and medium mean the most applicable for a small mammal surgery. A right angle applier is also now available, which is very helpful when placing clips deep into a cavity. So definitely something I would advise you to consider.

If we start looking into electronic and static devices, we then have a few options electrocoy, which uses electricity to hit metal till it is ready to coagulate tissues, but because of the heat causing damage to adhecent tissues, this is not of this is of limited. Value nowadays we tend to more commonly use in exotic animal medicine and more in particular in small mammal medicine, electrosurgery, which uses high frequency alternating current to generate energy. Bipolar forceps are primarily used for hemostasis, especially within the body cavities.

Then always consider the possibility of a carbon dioxide laser which produces a beam of light energy at a wavelength that is highly absorbed by water molecules and making it ideal for cutting with a focal beam or vaporising within tissue with a diffused beam. Obviously this may be more expensive equipment, but not routinely used in first opinion practise and then whenever possible where in those facilities where a harmonic system is available, this is an ultrasonically activated tissue cutting device which uses electrical energy which is then converted to mechanical energy. He briefly asked that this may not be readily available in first opinion practise, but the ligature system, which is a type of bipolar cautery that combines the tissue sealing technology with a monopoly and bipolar electrosurgery, can.

Certainly be used in small mammal surgeries as well. This is in particular a rabbit, but I've also used the ligature system in guinea pigs, for example, where I have to collect, as in this case here, liver biopsy. Gentle tissue handling is one of those aspects that becomes extremely important, especially when we are talking about smaller rodent species because it can help minimising the risk of addhes where we are handling obviously abdominal organs, especially the delicate gastrointestinal tract of some herbivorous species, but also when we are.

Tissue handling in terms of the skin, for example, because gentle technique can help minimising the risk of self-mutilation, which is a particular problem in some of the smaller rodent species. Pinching the skin with forceps during suture placement, for example, can cause bruising and irritation predisposing to self trauma. In placing sutures, and have a look at these pictures which are taken from the.

Ferrets, rabbits, and rodents, clinical medicine and surgery, use the forceps to provide counter pressure when passing a needle through the skin and guide the tissue rather than pinching by holding the skin edges. So these can be particularly useful. Often the skin of these animals is very delicate and we tend to get hold of it to be able to then perform some of the manipulations that we, that we need to do, for example, when placing the suture themselves.

Insert the forcep into the incision and then pass the needle between the tips as you can see in the second in image B and then pass the needle into the incision using the forceps on the outside for counter pressure and then exit the needle between the tips of the forceps. So try and think of these little tips when placing the sutures because this can definitely help minimising self trauma. In many of these patients, we are also doing intradermal sutures, but these can also help thinking when we are placing these sutures to minimise the irritation and the trauma to to the tissues which, as I said, there can be a particular problem, for example, in rats.

In terms of suture materials, these are the most commonly used types in a small mammals surgeries. I tend to prefer the use of monocreo and PDS wherever possible. Always remember to use the smallest size suture and needle to accomplish the task you need to accomplish generally from 4 to.

Not generally used for most rodents with small short, fine and swapped needles. Cutting needles are generally reserved for the skin. Aromatic tape pointing needles are recommended for soft tissues and as a general rule, monofilament rapidly absorbable suture material are most appropriate for most rodents.

Now 11 type of suture material that I came across a few years ago and that I started to use more and more frequently, especially in rats where the risk of self-mutilation following any surgical procedure is so high, it's called stratafi and is absorbable barbed, not less a tissue control device developed by EIO with the aim to facilitate the soft tissue approximation by providing the performance characteristics and wounds holding security of conventional PDS. Now the manufacturer claims that the tissue holding strength of stratafi is superior compared to PDS loop continuous technique, vir interrupted technique with a unique anchoring design delivering multiple points of fixation that help maintain approximation along the suture line during closure when obviously compared to tradition. Sutures.

So to, to say very simply, stratay is an absorbable suture material with little barbules to the side the literally anchors to the tissues where they used for and now obviously human medicine is often used used for the fascia, whereas I tend to use it more for the skin. It literally anchors to the skin without the. Need of making any loops and it reduces the risk of the rat in particular because I think it's the species where self-mutilation as with mice, for example, is particularly high, reducing the risk of them removing the suture material itself because there is not involved in it and the little bubbles simply anchors to the surrounding tissues.

Stratafi, obviously I don't have any, any big amount of data to say that this is the case. It's simply over the years that I've been seeing a difference so when this is being used in rats as opposed to conventional types of suture material. I also tend to use a tissue glue, the sunanoacrylate tissue adhesive, to sort of approximate little areas where, for example, the skin remains apart once the suture material has been applied.

Just remember that some of the smaller wooden species, in particular mice and rats, for example, Become quite fastidious groomers where a large amount of tissue adhesive is applied. So simply use one or two drops in the focal area where you need and don't use an excessive amount because this can further induce the risk of excessive grooming and interference with the wound. One last thing to remember with regards to suture material is to avoid chromic cat because of the risk of reactions to this type of suture material in small mammals.

General considerations in terms of patient preparation for general anaesthesia and surgery are standard as a technique that should be adopted for any patient and in particular for any exotic mammal patient undergoing any type of surgical procedure, especially where as This case, for example, this is a guinea pig that is prepped for pre-scrotal open orchiectomy. Obviously this is a type of procedure which has a high risk of postoperative complications, for example, infection and abscess formation. So even more so in this case the standard aseptic technique is essential.

Because these species have a very high body surface area to volume ratio, and hypothermia is a big concern. Avoid excessive clipping because this can predispose them to hypothermia as well and avoid damaging the skin because it is extremely delicate in the majority of these species. The use of a clear plastic drape is preferable.

Because it sort of retains a part of the heat because they are made of plastic, but also because they are clear, they allow easier mon monitoring of the patients as compared to traditional surgical drapes. And finally, patient monitoring, we are obviously talking about surgical procedures and therefore we are talking about general anaesthetic is essential. We've already mentioned briefly the use of checklists.

Checklists have been implemented for years in human medicine as well as in veterinary medicine because there have been several human and veterinary studies showing that implementation even of brief short checklists can reduce. The risk of complications can allow early identification of problems and their correction at an early stage before complications occur. We generally use a very brief checklist in our clinic which includes the identification of the patient, checking of the anaesthetic machine, checking of all the drugs, and work out of the doses of the emergency drugs as well as the use of postoperative drugs, the need for radiosurgery, for example.

So this is something that simply allows minimising the time during which the animal is anaesthetized and the surgery time which ultimately can increase the possibility of a positive outcome. Patient monitoring is essential throughout the entire procedure. This means checking the vital parameters, so heart rate, respiratory rate, temperature, mucus membranes, colour, and dryness throughout the entire procedure at very regular intervals because this also.

Gives us an indication of how the animal is performing throughout the procedure and allow us to identify problems at an early stage. Remember that the complication occur much faster in these species and therefore time of intervention is much reduced as compared to more traditional species such as dogs and cats. Remember the possibility of performing intrapositive pressure ventilation, so using a mechanical ventilator, obviously if the animal is intubated and this is even more so, for example, in chinchillas and guinea pigs that can be more readily intubated as opposed to smaller species, the use of carnography, which is much easier obviously if the animal is intubated, the use of Doppler, this is something that I do use quite a lot.

The presence of a Doppler placed over an artery or more simply over over the heart allows continuous monitoring of the heart rate and rhythm throughout the procedure, makes the entire room so all the people involved in the procedure aware of of the of the heart rate and of any change in trending of these heart rate. Throughout the entire procedure allows determination, as you can see in this in this picture of the blood pressure whenever, whenever possible and also avoids interference with other types of electoral activity which may occur, for example, if you are using an ECG. A pulse oximeter may be used as well.

There are some unreliabilities with the use of this machinery because the The oxygen level can drop quite significantly before this is indicated by the machine itself, so something that can be used but not necessarily so reliable in these species. And then again we've already mentioned the possibility of monitoring the blood pressure as well, probably better in larger species and depending on the cough size and which you are using as well. In the last part of the talk, we'll discuss common surgeries in different rodent species.

Please remember that many of these surgeries can be simply extrapolated from one species to another, and then we'll discuss postoperative care. First, the procedure that will be taken into consideration is the orchidectomy. The primary indication for this procedure in rodents is to prevent breeding because generally it is much easier to castrate males than to spay females.

It is also reportedly helpful in decreasing the risk of urethral blockage due to urethral plugs. Another important indication for orchiectomy is the treatment of testicular tumours which are especially common in rats and in gerbils. There is instead no evidence that orchidectomy ameliorates aggression in rodents.

It is therefore indicated or suggested that orchiectomy should be performed prior to puberty because once the sexual behaviour is manifesting, then they become learned behaviours and therefore not necessarily affected by the loss of hormones. Just a few anatomical notes, the testicles of most rodents are comparatively large and are located called ventrally. Myomorphic rodents, for example, rats and similar type rodents are well developed scrotal sacs.

To the penis, whereas trichomorphic rodents such as the guinea pig that we will be taking as an example over the next few slides, do not have well developed scrotums and instead their testicles are located bilateral to the penis in the inguinal region. It's important to remember that the inguinal canals remain open and that a functional crema stem muscle muscle allows the testicles to migrate in and out of the abdominal cavity, so the testicles can be easily pushed back into the scrotal with gentle rolling and cardio ventral pressure just cranial to the pubis. Now, with regards to orchiectomy, there are different approaches, so the pre-scrotal, scrotal, and abdominal approach and different techniques either open with subsequent closure of the vaginal tunic or closed.

In this specific case. Will consider the pre-scrotal open orchiectomy, which is my preferred or was at least my preferred method for castration of male rodents and the abdominal approach, which is now, now my preferred approach to this procedure. The next few Pictures are courtesy of Doctor Victorio Capelo, and I thank him very much for this, for his help.

Now, we've already discussed patient preparation, incisions are just bilaterally to the side of the penis and just the cranial to, the scrotal sac. We identify the vaginal tunic and we exteriorize the, the testicle with the epididymus and the epididymal fat. Now the epididyal fat extends bilaterally into the abdominal cavity near the kidneys and may be responsible for preventing intestinal herniation.

Together with the testicular artery and vein, this fat passes through the inguinal canal and into the scrotum. Pictures so you can see here the spermatic cord, the testicle, the epidids epididymis, the difference that, and at the bottom the the emmiscrotal sac. Now according to some authors, the preservation of this fat may decrease the risk of visceral herniation after both open or closed orchiectom means more rodents, however.

This risk has never been clearly documented because of their anatomy, Inguinal hernias are very rare in these rodents with appropriate technique and visual herniation after orchidectomy has actually not been reported. However, some authors do not remove the epididium or fat during castrations where others removed. The fat ligating just the vaginal tunic as proximal as possible to prevent herniation and to date with removal of the fat, post castration scrutal herniation have actually not been encountered and one of those actually removes this ep fat without having seen any problem.

You can see here we are ligating the the the vessels. In this case this author has clamped, removed, and then ligated. I actually prefer doing the contrary, so clamped, ligate, and then removing the the stamp, the testicular stamp.

In the second picture here, the vaginal tunic is. Closed once the fat, the remaining fat and the stump has been replaced into the abdomen and then the skin is closed as routine. So you can see in the last picture the bilateral incisions that have been made cranial to the the the scrotal sacs and to the side of the penis.

Now, as I mentioned briefly, according to some authors, that the risk of herniation following castration is not particularly elevated because of the presence of the epididium or fat pad within the vaginal tunic, which would pre pre prevent. These complications and which should therefore be preserved during castration. On the other hand, there are many authors that do remove this fat pad, including myself, without having seen any of these complications during the years.

In particular, though I would like to show you this picture, this was one of the only cases of bladder herniation which I saw in the last 10 years. This was following a procedure performed by a colleague, which was inexperienced with the procedure. Did not close the vaginal tunic following a scrotal approach to castration.

I have to admit, however, this is not something that I do see routinely when the procedure is performed with the correct technique, either for removing or not the epididyal pad. I mentioned earlier on that the pre-scrotal open orchiectomy was my preferred approach to this procedure in male rodent species, whereas nowadays I tend to prefer the abdominal orchiectomy for all male rodent species. Now in 2015, 2 surgical approaches were compared, in particular the scrotal.

The abdominal approach to castration of guinea pigs were compared in terms of infection rates and suitability of either technique. During this this study, 48 guinea pigs were castrated by either technique with either by either an experienced exotic animal surgeon or by an experienced small animal surgeon. The study suggested that postoperative infection rate was significantly higher in the scrotal group and obviously this is no surprise as the scrotal area is very close to the bedding, and this is one of the most common complications that we see following this approach, and that's the reason for the pre-scrotal approach as opposed to the scrotal one because the area is.

Less likely to be soiled due to its anatomical location as opposed to the abdominal group which had a higher rate of or a faster rate of recovery as opposed to the other approach. So obviously in this study, the pre-scrotal approach was not compared to the abdominal one, but the scro. One resulted in much higher rate of complication in this species, and that's the reason why I started moving towards the abdominal approach which I now find much easier in terms of technique and in terms of recovery from the procedure which appears to be actually much faster compared to the previous one I was used to.

So let's discuss more specifically about this abdominal approach to orchiectomy in rodents. Now, even in adult rodents, the inguinal canal is very large and large enough for the testicles to move freely into the abdominal cavity. Therefore, they can be removed throughout.

A small abdominal incision, usually a 1.5 centimetre skin incision is made between the umbilicus and the penis, and a routine caudal abdominal ciliotomy is performed to gather abscess to the abdominal cavity. Then gently apply some pressure onto the scrotum and push the testicles into the abdominal cavity, identify the testicles or the epididal fat pad.

Bilaterally to the blood and gently exteriorize the testicles through the skin incision. Then carefully separate the ligament of the tear of the epididymus as you've done through the approach that we've earlier discussed from the internal surface of the vaginal tunic and replace that back into the ab. Ligate the vessels and basa deference as routine as you've previously seen with the other approach and then remove the testicles and epididal fat is that if that is what you routinely would do and then repeat the procedure with the contralateral testicle and then close the abdominal cavity as routine.

When discussing about surgery of the female reproductive tract, one must distinguish between ovarcul hysterectomy and ovarectomy. Now indications for neutering female rodents mainly include the controlling reproduction, preventing and treating dystopia, treating cystic ovaries, other types of uterine pathologies, reducing the risk of mammary and pituitary tumours, for example, in rats or even suppressing anxiety. There are some lab works which show that compared with in rats, those overreact to mice at a young age at adulthood, so respectively 3 and 6 months old, compared to 18 months old, that demonstrated significantly reduced episodes of behaviour consistent with anxiety.

But whether this is the same in domestic settings is very difficult to say. In laboratory rats as well, ovarectomy before 7 months of age has been shown to significantly decrease the risk of development of mammary neoplasia. Ovareectomy is the female rats also have a significantly lower incidence of pituitary tumours and a higher survival rate today, 630 compared to intact female rats.

Now in most species of ovarectomy at a young age is effective at preventing uterine disease. Therefore, unless uterine pathology is present at the time of surgery, then ovarectomy is preferred over ovarian hysterectomy because of the common occurrence of ovarian disease in companion rodents and particularly in guinea pigs, routine juvenile ovarectomy should be considered as a preventative measure. Ovariectomy is generally easier to perform and causes less morbidity, especially in young healthy animals with normal ovaries as compared to older animals with possible ovarian pathology.

In guinea pigs with cystic ovaries, ovarian hysterectomy is the treatment of choice because uterine disease, secondly to ovarian cysts, is very common, although the mechanism has not yet been established. Now, with regards to the anatomy of the female rodent, reproductive tract varies slightly by species. Generally, the ovaries are located quadolaterally to the kidneys but very deep into the abdominal viscera, and that's why, for example, ovarectomy in guinea pigs, especially via the ventral approach.

Not so easy as in other species. In guinea pigs, the oviduct lies in close proximity to the dorsal aspect of the ovary and certainly before joining the uterine horn, and then the suspensory ligament is quite short in this piece is making the hysteriorization of the ovaries particularly challenging. Now ovarectomy and ovar hysterectomy can be performed through either a ventral midline approach, as you can see in this picture here.

This is a normal routine, let's say spray in a guinea pig. You can see the uterine horns, the cervix, which is very short, and the urinary blood. It's very difficult to exteriorize as I was mentioning the ovaries and therefore the lustre retract.

I mentioned at the very beginning of the lecture becomes extremely helpful in in this situation or it can be performed through a flank approach which can be dorsolateral or bilateral, and we'll discuss this in in, in the next few slides, and I thank once again Dr. Vitorio Cabello for the pictures that have been provided for, for. Lecture.

Remember that when the incisions are made bilaterally and dorsally, they are not subject to the weight of the viscera. There is also less morbidity because the incisions are smaller and the procedures can be performed relatively quicker compared to a ventral midline approach like the one showed here once again. So it is also my clinical experience that the post-surgical pain may be.

As compared to this approach, the primary disadvantage of the flank approach is that it can be more difficult to access the uterus if ovari hysterectomy is necessary. Now I'm not discussing the technique to perform vari hysterectomy because this is routine as you would perform in other species of ovaries and uterus as are removed as a routine in this species as well. So just to recap very briefly, the main advantages of preventative ovarectomy, at least in young animals where uterine pathology is not present or supposedly not present as opposed to a full vacular hysterectomy via the ventral midline approach, is the fact that with the flank approach, the gastrointestinal tract does not have to be manipulated.

The incisions are doors. So they are not subject to the weight of the viscera and also morbidity is less because the incisions are much smaller, so the procedure can be performed relatively quickly and the post-surgical pain seems to be much less with this approach as opposed to the ventral midline approach to the procedure. The primary disadvantage is that it can be more difficult to access the uterus if ovarri hysterectomy is necessary.

Now, to perform the procedure, and we'll discuss this on on a guinea pig as you can see in in this case, both flanks should be shaved and surgically prepared, as well as the abdominal skin just in case a ventral midline ceotomy should become necessary because of complications, for example, or Because of an unexpected uterine pathology. In this case, the is not being fully clipped, but it's for showing purposes for teaching purposes. Now, to perform the react in a guinea pig or in a rat, for example, 12 to 2 centimetre incision can be made on each side, so the procedure is.

From the one side first, then the animal is replaced onto the opposite side and the area surgically prepared again. So if you have a look at the second picture, the black line indicates the level of the erectal spiny muscle, so it's just at the level of the vertebra, whereas the blue line is the level of the last, the last rib. So the skin incision is made.

Just between this line, as I was saying, 1 to 2 cm incision, just approximately 1 centimeter/4 to the last rib. Then the skin is inside. We go through the subcutaneous tissue and the muscle to gathers access to the abdominal cavity, as you can see in the last.

And then simply press the ovary to the incision by applying gentle pressure onto the abdomen, grasping the ovary with the forces. Generally, the fat simply comes out of the incision. However, sometimes we have to do some, let's say fishing through the fat to be able to exteriorize the ovary.

There may be sometimes associated little variances. In some cases they cannot be exteriorized through the small incision. Then in this case, obviously the incision can be enlarged enough to allow exteriorization of the ovary with the associated cyst or fluid that can be drained to the point of allowing ovarian cys.

To be exteriorized exteriorized the ovary, and he hemostatic clip or a ligature can be used to ligate the ovarian vessels and take care to remove the entire oviduct surrounding the ovaries as well. Experienced surgeons, sorry, are able to remove both. There is a neutering horse through one side, especially in younger animals, but I find this particularly challenging in a guinea pig.

I tend to prefer doing both sides separately whenever possible. However, if necessary, the approach, as I was saying, can be repeated, and I find it much easier on the opposite side. So in this case here you can see that part of the uterus has been left in place because no associated uterine pathology is present, but experienced surgeons are able to remove quite a significant part of the oviduct and in some cases of the cervix as well, and to repeat the same procedure from the same side as opposed to flipping the animal on the opposite side and making a second incision.

Once, the, the, the ovary has been removed, then the stump is, checked and, replaced into the abdominal cavity. The muscle layer, the subca, and the skin are then closed as routine. And this is the appearance of the skin.

This is was a post-op check, but following this this procedure, you can see already the fur regrowing, but you can see how small the incision is along the flank as opposed to a larger incision on the ventral midline in case of a ventral approach to ovarectomy or ovar hysterectomy. Just out of interest, this article was published in 2016 and reported the unilateral flunkovar hysterectomy in a guinea pig. More in particular, this picture taken directly from the article shows an eight month old female guinea pig undergoing ovarri hysterectomy via the unilateral flank approach at the at the start of the procedure, the term.

In the incision site which for these orders was at the intersection of two imaginary lines which are the two red lines on the image perpendicular to the longitudinal body axis behind the last rib and parallel to the longitudinal body axis below the transverse processes of the thoracic and lumbar vertebra. The skin incision is about 1.5 to 2 centimetres long and parallel to the spine.

Still from the same article you can see a view through the incised the skin, dissected abdominal muscles and peridoneium revealing the fat in the broad ligament of the uterus. A circumferential ligature is placed on the ovarian mesentery and vessels of the ovary, which is indicated by a black arrowhead. In the first picture, and then you can see ligation of the broad ligament of the uterus and finally placement of a transfixing ligature around the cervix in the third picture and then the view of the surgical wound 4 days after unilateral flank ar hysterectomy in this very young animal.

Now just out of interest, I thought I would suggest you another read, a slight variation in the technique which is which I've just described, which is the dorsal overreactomy in rodents. More specifically, this was published in rats, but the procedure can certainly be applicable for use in other rodent species as well. Now the next few pictures are taken directly from this article author suggests in order to perform this technique to clip a square of skin centred approximately at the level of the 3rd lumbar vertebra and extending 2 or 3 centimetres later to the dorsal spinous processes.

Now either one or two small skin incisions are made, so the author suggests that I The bilateral skin incisions, as you can see in this case, are made on each side of the patient, approximately 1 centimetre ventral to the dorsal spinal processes of the third lumbar vertebra, immediately cord to the last rib or one single incision on the dorsal midline which is then pulled to either side of the patient to gather access to the abdominal cavity. Once the abdomen is entered, then the ovary and the associated fat is identified ligated in this case a pneumoclip is being used. The stump is replaced back into the abdominal cavity, obviously you can see that these are very young animals with no associated uterine.

Pathology, so only an ovarectomy is performed. The abdominal cavities, so the muscle layer, the sub and the skin are closed as routine. Skin closure can be achieved with suture material or as in this case with a staple.

Ovarian cysts are commonly found, especially in guinea pigs. They tend to be reported in 66 to 75% of females between an age of 3 months to 5 years, but they tend to be more commonly found in older animals. There are two main types of ovarian cysts, the scirocysts, which are the most common.

The type found in guinea pigs and tend to arise from the rear are intra ovarian and physiologic occurring throughout the reproductive cycles. These types of cysts appear to be nonfunctional, so non hormone producing as opposed to the follicular cysts which are found less commonly and are instead steroidogenic. Now, there seem to be no significant correlation between the reproductive history of an animal and the prevalence of the cysts, but other problems are commonly reported concurrently with ovarian cysts, including leiomyomas of the uterine structures, granulosa cell tumours, cystic endometrial hyperplasia, and endometritis.

Now, as mentioned, scirocysts are not hormone producing. They may be single or multilocular. They're usually filled with clear fluid.

They can range in diameter from 0.5 to 7 centimetres or even. And they tend to increase in size and prevalence as the animal ages, but because they are not hormone producing, they don't tend to cause evident clinical signs and then unless they are very large and starting to compress abdominal organs like in this case.

Very large cysts can cause abdominal distention, can obviously result in anorexia, weakness, depression, or even hunching in pain. However, remember that other disease processes can be responsible for the same clinical signs and that variances may be simply an incidental finding in those animals. On the opposite hand, follicular cysts, because hormone producing usually associated with bilateral symmetric nonpro flank alopecia as well as mammary hyperkeratosis.

So as you can see in these animals, there is a bilateral symmetrical alopecia of the ventral abdomen of the flank as well. And in this amnio you can see hyperkeratosis of the nipples. Sometimes the nipples are also quite crusty as well.

History and physical examination are generally strongly suggestive of ovarian cysts in guinea pigs. Other diagnostic modalities such as amato biochemistry and urine analysis, hormonal essays, and radiography may be particularly helpful in evaluating the general health status of a patient, but not specific for the. Diagnosis of ovarian cyst.

The only imaging modality that allows identification of ovarian cysts is the ultrasonography. Cysts are generally variably sized anechoic, unilocular, or multilocular filled with a variable amount of fluid and contiguous with the ovaries and dorsally to the kidneys. Now several attempts to resolve ovarian cysts with medical therapy have been tried over the years, and this may include, for example, percutaneous drainage of the cysts, injections of human chorionic gonadotropin, injections of leuproli acetate, as well as the use of the loinin acetate implants.

However, all these medications may not achieve. The outcome hoped for, especially where serosy are present, which we already discussed, do not produce any hormones. Therefore, the main, the main treatment for ovarian cysts seems to be a surgery, whether ovarectomy or ovarian hysterectomy.

We've already discussed that cysts are often associated with uterine problems. In these cases, obviously ovarian hysterectomy is mandatory. As for the technique, obviously remember that overreactomy may be performed even when cysts are present from the flank.

In this case, the drainage of the cyst prior to exposure of the ovaries and associated cysts may help in manipulating the tissues, whereas in many cases, the ventral midline approach may be preferred, especially where ovar hysterectomy is performed. However, there are many colleagues that do. For a complete hysterectomy even when it's present from the flank approach so it simply what is the surgeon's main preference.

I find it particularly difficult to exteriorize and remove the oviduct from from the flank approach, but obviously something that you may need to to experience, to have experience with. Just to briefly mention another species, ovarian disease, whether cystic or neoplastic can be seen in other rodent species. For example, this is a Russian dwarf answer that was presented for bilateral symmetric non-pruit lopecia.

In this case, obviously. The diagnosis a pre-surgery was a cystic disease. At that time we weren't sure whether it was a new plastic or not, but the hamster was brought to surgery, and you can see pictures taken intraoperatively in in this in this patient.

As you can see, the technique is not very different compared to the one that we've discussed for guinea pigs, but with the added complication of the small size of the patient. In this case, adequate suture material of appropriate size for the species was chosen, but you can also opt for hemoclips for vascular closure. In this specific patient, and I'll just mention this in the next slide.

The cystic disease was neoplastic, so, the, the sample that was sent off for histopathology and the pathologist confirmed that the ovary was affected by a granulosa cell tumour. When talking about mammary gland neoplasia, the first species that comes to mind is certainly the rat because these type of tumours are particularly frequent. They are usually benign.

We tend to encounter mammary fibroadenomas which do not metastasize at least in the majority of cases because the mammary tissue in this species is particularly extensive. Any lump arising along the body of the rat may be suspicious for a mammary neoplasia. This type of tumours can therefore arise anywhere from the neck to the inguinal area and can become particularly large, sometimes compromising even the functionality of the genital or the urethral opening.

So, in some cases, these type of tumours that can become quite large and in certain anatomical area can represent a surgical challenge. As a general rule, surgical treatment of mammary neoplasia consists of excision of the tumour and associated mammary gland and then in some cases obviously performing ovarectomy, but we'll discuss about this in a short while. However, because of the extensive nature of mammary tissues, in rats as well as in mice, a total mastectomy in this species is not practical.

Therefore, it is important to try and remove the tumour, but aiming to removal of the entire. Tissue is not possible. As you can see in in these few slides, this rat is being anaesthetized and local anaesthesia is applied and then the tumour is excised as routine.

Bluntly dissect around the mass as you would do for other species as well, ligating the vessels that they are encountered, and this can be achieved by a combination of electrosurgical dissection or laser dissection, or you can use tissue sealing devices or immo clips like in this case. Remember that some of these masses can be particularly large and therefore the that space may be significant to help reduce that space, tuck the skin and subcutaneous tissues to the body wall. However, be aware that hacking can cause irritation and stimulate the postoperative chewing of the incision site, which is a particular problem in this species.

Because mammary gland tumours are hormone sensitive, a prophylactic ovarectomy before 5 to 7 months of age is associated with a significantly lower incidence of mammary tumours in this species. Therefore, ovarectomy in young rats is recommended to prevent further tumour development. Currently there is no evidence.

Ovariectomy after 7 months of ageing rats with mammary tumours is effective in preventing recurrence or further mammary tumour development. In one study, 3 rats that underwent ovarian hysterectomy concurrently with a mammary tumour excision or 7 months after developed the subsequent mammary tumours within 13 months. However, it's important to remember that neutering will not prevent a further development of preexisting mammary tumours, but it will prevent uterine diseases and decrease the influence of oestrogen hormones on existing tumours.

Therefore, it is important to consider and discuss the benefits of this with with clients. Now it has been suggested that if abdominal surgery cannot be performed to neuter the rat at the time or shortly after the removal of mammary tumours, then a dislo implant can be placed subcutaneously to suppress the hormone production. However, in this study where a 4.7 milligrammes.

The implant was placed within 2 months of a benign mammary tumour surgical excision. The hormones were not the hormone implants were not associated with a decreased risk of developing subsequent pulmonary tumours, nor with an increased survival rate in female rats. Therefore, the debate remains open.

Eurolithiasis is another common condition seen in several rodent species more frequently reported in guinea pigs and therefore I will concentrate on the species for specifically this pathology. Now the pathogenesis of eurolysis in guinea pigs is not well understood, and several factors have been proposed as contributing to this pathology, including, for example, in genetics, diet, in particular, diets comprised of high quantities of some dark leafy greens or provision of alfalphahae have been proposed as inciting causes for calcium. Based eurolithiasis development, but alongside these conditions that can lead to cystitis and nephritis have also been proposed as contributing factors.

Other hyperized risk factors for urolithiasis may include overconditioning, inadequate environmental cleanness, stationary lifestyle, urine retention, dehydration, and renal disease. Now, urli have been reported throughout the guinea pig's urinary system, but they are more commonly observed in the urethra, as you can see in these two pictures. And in the bladder, as you can see on the right hand side, the picture of the screen, less frequently, but usually guinea pigs have also been reported in the seminal vesicles of males.

In the kidneys, as you can see on the left side picture and in the ureter as well, as you can see in the picture on the right side of the screen. Clinical signs of urlithiasis are similar to those in other mammals and are generally depending on the size and location of the stone or stones present. These may include mtuition abnormalities such as hematuria, for example.

Always remember that in females, the vaginal opening and the urethral opening are separate and therefore it should be fairly easy to identify where the blood is coming from when it is seen from the back end. Other tuition abnormalities may include stranguria, dysuria, anuria. There may be signs no specific clinical signs, including, for example, anorexia, lethargy, and apparent discomfort manifesting such as teeth grinding or hunched posture.

Diagnosis is generally based on a combination of clinical signs, physical examination findings, and results of laboratory and diagnostic imaging. Ultrasonography is useful for anatomic localization of the calculi and for evaluation of anatomic changes within the kidneys or ureters. A contrast urethrogram may be useful in male guinea pigs to determine the location of the stone, whether an escrete or intravenous pyelogram or contrast the CT are particularly useful to.

Further elucidate relative functional abnormalities in the kidneys or ureter. In the suspected cases of urolithiasis, it is always important to evaluate the hemato biochemistry as well as performing the urine analysis and if possible, a urine culture as well to evaluate the general health status of the patient as well. Rigid endoscopes can be particularly useful in many cases of eurolithiasis because they can be used in female guinea pigs for cystoscopy, so for diagnostic purposes as well as for stone removal.

Now medical treatment of eurolithiosis has been unrewarding to date, and neuros smaller than 5 millimetre. Diameter may pass an aid because of the large diameter of the urethra in both male and female guinea pigs, but cystoscopic removal can be particularly useful in some situations where the stones are not so not so large and therefore are not able to pass any needle through the urethra. Wherever a cystoscopic removal is not possible, then a surgical approach may be required, and this obviously depends on the anatomical location of the stones.

Cystoomy may be performed as routine, the incision one. Gather the access to the abdominal cavity is made along the ventral aspect of the bladder and usually closure of the bladder is achieved with a very small sized monofilament absorbable suture material. In cases where the stone is located within the ureter, then a different procedure may be performed, which is the ureterotomy.

However, this type of procedure carries severe risks of stricture following the suture of the very thin and small sized ureter in this species. Small to medium sized calculi that are located at the urethral orifice in female guinea pigs can be manually expelled under general anaesthesia. However, in some cases, a lone star retractor, so a gentle retractor may be used to facilitate a removal of these stones of the urethral orifice.

We now discuss the several surgical procedures that can be performed in different rodent species. It is now important to also take into appropriate consideration the postoperative care because this is as important as the surgical procedure itself for a positive outcome. The first consideration to make is the post anaesthetic monitoring.

It is important to remember that many of the deaths that are recorded in rodents do occur not just during the procedure itself, but in the post anaesthetic period as well, often because the patient is placed back into the. Or the enclosure without the necessary monitoring. It is therefore important to consider closer monitoring in the immediate post anaesthetic period and then delaying or continuing to monitor but at a longer interval once the patient is able to ambulate and able to maintain his own temperature.

And then appropriate consideration should be given to medical therapy, and this may include analgesia and antibiotics, and we'll discuss this in a short while, as well as providing supportive care such as fluids and nutrition. Wound management is something particularly important, especially in rodent species that can be fastidious. Groomers that can be interfering with their wounds more frequently as opposed to other mammal species.

Therefore, wound management is extremely important, and this may imply, for example, the use of small animal jackets such as the one that you're seeing on the right hand side of the screen, but there are many that are available commercially. And this also implies, for example, preventing poo dermatitis, so for example, providing a large amount of appropriate bedding, includes evaluation or continuous assessment of the surgical wound, for example, by using a collars that may be particularly interesting to use in rats which are very prone. To attack, to traumatise a surgical, a surgical site in this species it is always very important to provide another analgesic plan that may reduce the interference with with the surgical site.

Bandaging is not something that is routinely done in this species because It can usually is not tolerated very well. It can be particularly stressful for some of the species and is generally removed within a very short period of time. But destructuring tactics may be used, for example, honey painting and other important considerations to make to prevent primary self trauma or.

May imply the use of some sort of protective restraint devices, for example, Elizabethan colour, although these are not particularly well tolerated or a sharp sharp bandage, for example, or other type of vests that may prevent the the patient from interfering with with the surgical wound. Traditional support is extremely important or I would say essential for all the small mammal species which have a very high metabolic rate. It is therefore essential to provide them with the adequate recovery formula for the species that you are taking into consideration, whether a herbivore or an omnivorous species, and to provide the nutritional support as soon.

As possible following a surgical procedure to prevent hypoglycemia and to support their high metabolic rate, it is therefore important to have available within your clinic several commercial formulas that may be available on the market to meet the demand and the taste of your patient as well. Usually syringe feeding is well accepted by most small mammals. Guinea pigs tend to take it voluntarily.

There is generally no need for excessive restraint. They can be gently but firmly hold while they are syringe fed, but there are usually no major problems in syringe feeding the species. Chinchillas may, the syringe feeding may be best achieved at the patient's own pace, avoiding excessive handling, and they usually tend to take this voluntarily even off a spoon or directly from a syringe.

As for the small rodents such as rats or hamsters, they usually take it quite volunta. And it is best to offer the syringe feed as soon as locomotion is evident, so immediately following an anaesthetic or whatever surgical procedure they have gone through. Always ensure that the coat is not wet or soiled and clean their chin after syringe feeding to prevent dermatitis in these areas.

Another important aspect to take into consideration and even more so following a surgical procedure is whether antibiotics may be required. Obviously this may not be necessary if the procedure was sterile and it is always important in any case where the antibiotics are to be used to try and achieve a definitive diagnosis wherever possible and where applicable, always use. And sensitivity to direct your antibiotic use and always prevent whatever possible antibiotic resistance by an appropriate and adequate use of antibiotics.

Always remember that some antibiotics may be particularly dangerous in one species as opposed to another, and because enterotoxemia is particularly relevant in many of the small mammal species. The use of probiotics. So while, antibiotics are being used is quite controversial.

We don't have any information on whether they do work or not. We certainly know that they don't harm, but there is no data regarding their use in small mammal species. Adequate analgesia is another essential component.

I I also mentioned this aspect which is often not considered sufficiently, which is referring. Referrals should be considered when a procedure or when the care of an exotic pet, including rodents, is out of the practise area of competence. This should never be considered a failure actually.

On the contrary, this demonstrates the provision of the best care possible for the patients that you are that you are in your care. Having a contact number readily available is also always useful because asking advice at any point should never be feared. This is always the best choice when there are any doubts in dealing with a species you are not familiar with.

So what's the take home message today? Now, first of all, remember that you have developed surgical skills by dealing with dogs and cats every day. Simply use these established skills, adapting them to species specific requirements when dealing with rodents.

What it is important to remember though is that knowledge of species specific anatomy and physiology is Critical in all these situations as well as preparation and planning ahead because this allows you to identify problems at an early stage, allows you to maintain the patient under general anaesthesia for the time that is required, therefore maximising that time and allowing you to reach a positive outcome in the best possible way. Thank you very much for listening and for your attention so far.