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This article is from the Rat Health Care booklet. Order one today! Check out the info at Rat Books

Surgery in Rats

By Debbie “The Rat Lady” Ducommun

There are several things you should discuss with your vet before scheduling your rat for surgery. Fasting overnight before surgery is standard for cats and dogs to prevent vomiting while under anesthesia. Rats have a flap in their stomach that covers the esophagus and prevents both vomiting and burping, so fasting before surgery isn’t necessary for them. Rats do most of their eating at night and an overnight fast will deplete their energy reserves. Fasting can cause hypoglycemia and dehydration, which, along with hypothermia, can cause anesthetic complications and death. However, you can withhold food for 2 hours before the surgery.

When taking your rat to the hospital for surgery, make sure the cage has food and water. It may be a while before the surgery. Food and water should also be offered to the surgical patient at the hospital as soon the rat awakens from the anesthetic, so also discuss this with your vet and the veterinary assistants or technicians.

If the rat is going to have surgery on the intestines, a vet might request a fast to reduce the intestinal contents. Discuss this carefully with your vet. Perhaps a liquid fast might be possible. Fasting longer than 2 hours is definitely not necessary for routine surgeries such as spays, neuters, and tumor removals, so if the vet or receptionist still asks you to fast your rat overnight, ignore it.

It’s very important that rats be kept warm during surgery. General anesthesia prevents normal temperature regulation of the body and it can take several hours for normal temperature regulation to be restored. Rats are so small they lose body heat rapidly and if heat is not supplied, for instance by a heating pad, they can easily die from hypothermia. Not all vets realize this need for rats. Heat is not always supplied for cats and dogs undergoing surgery, although it probably should be; a study found that when heat was supplied for human surgical patients, they recovered more quickly and had fewer infections.

Antibiotics to prevent infection are recommended, especially for neuters, major surgeries, for older rats, or if a rat has other health problems. If a rat who has previously had respiratory symptoms needs surgery, she should be put on antibiotics suitable for mycoplasma several days before the surgery to help protect her against a relapse during the stress of surgery. Continue giving the antibiotics until after the incision has healed.

Unless there are complications, you should be able to take your rat home the same day as the surgery. I do not recommend a rat spend the night at the hospital, and especially not if there will be no one to check on her. In fact, it’s best to schedule the surgery on a day when you will be home afterwards so you can keep an eye on the patient in case of bleeding or other problems. A rat may be sleepy from the anesthesia and analgesia that day, but should be back to normal the next day.

Roommates

Once the patient is fully awake, and there are no complications, most rats can put back with their roommates for comfort and warmth. A rat will rarely bother the incision of another rat unless she is an obsessive groomer or barber. Most vets recommend that a surgical patient be isolated from other rats, but I disagree. I don’t think there is any need to keep a surgical patient isolated. It is very rare for a rat to bother the incision of another rat. I only know of a couple cases where a roommate was an obsessive groomer. Once a rat has completely recovered from the anesthetic, she can be put back in with her roommates. This will make her feel more comfortable. Keeping her isolated will cause her stress which will delay healing.

Anesthesia and Analgesia

Only inhalant anesthetics should be used for rats. This is so the level of anesthesia can be carefully controlled. Discuss this with your vet. Injectable anesthetics can be deadly since they cannot be precisely controlled.

Not all vets give all their surgical patients analgesia, so you must ask your vet to give your rat an injection. Butorphanol is both an analgesic and a sedative to make the rat more comfortable after surgery and is the one I use. Butorphanol should only be given after the surgery, and never before the surgery (a so-called pre-anesthetic) as the combination of the sedative and anesthetic can be fatal for rats! The pain medication buprenophine is less of a sedative and is the only analgesic that can be given before the surgery.

After a spay or neuter, the patient can experience severe abdominal cramping after the surgery and up to 3 days afterwards, so analgesia is highly recommended for these surgeries. Tumor removals are less painful, but analgesia may help prevent rats from chewing out their sutures.

For rats with congestive heart failure or labored breathing who would be at risk for general anesthetic, some minor surgeries, such as removing a subcutaneous tumor, can be done without general anesthetic. I have done four surgeries on rats with known or suspected heart disease to remove small tumors from the side or back (2 fibromas and 2 fibroadenomas) using this method. I used butorphanol, a sedative and analgesic, at a dose of 3-10 mg/lb (depending on the rat’s tolerance; normally 3-5 mg/lb) to sedate the rat. At this level of sedation, the rat remains on her feet and requires manual restraint by a second person. The rat does not usually react to incision of the skin, but does react with squeaking and slight struggling when subcutaneous tissues are separated, requiring local anesthetic.

Tumor Surgery

Removing small benign mammary tumors, up to the size of a walnut, is quick and easy—commonly there isn’t even any need to tie off blood vessels; the tumor can be removed with blunt dissection. Larger tumors often have several blood vessels that need to be tied off, and excess skin will also need to be removed. Any loose hanging skin remaining after the surgery will likely result in a seroma.

The Incision

When the incision will be small, as for a spay, subcuticular sutures may be used. This technique hides the sutures within the incision and it is very rare for a rat to chew them out. However, for larger incisions which need more sutures, such as for large tumors, rats often have an inflammatory reaction to the absorbable sutures.

Large incisions can be closed with staples, or I like to use Michel wound clips. I find that the belly skin of rats tends to be too thin for staples, and the width of the clips means I can use fewer of them. Steel wire sutures are more resistant to being chewed out, however if a rat wants to remove them, she will, even if she has to tear the skin to do so. Staples and clips resist casual exploration by the rat, but can be removed with minimal skin damage by a persistent rat. In some cases, surgical glue can be used but rats often tear the glue open.

Check the incision daily for any problems. Normal healing can cause some swelling and redness but a large amount of swelling, pus, drainage, greenish skin, or a bad smell can indicate an infection—contact your vet immediately. Staples can generally be removed 10-14 days after the surgery, or if necessary, they can stay in much longer.

An abscess is a common complication after a neuter done through the scrotum, but in this case it is usually a sterile abscess due to a reaction to the sutures, not an infection. This usually occurs about 2-4 weeks after the surgery while an infection will usually occur within a few days. Once the abscess opens and drains it usually clears up quickly. (See page 26.)

Protecting the Incision

The most effective methods to protect an incision are with a body cast or cervical collar. These restraints are quite upsetting for the rat so they should only be used if the patient has actually chewed open her incision, has a history of chewing her incisions open, or if the incision is particularly large, or if the owner would have trouble getting back to the hospital to have an opened incision re-closed. I do not recommend the routine use of these methods for every surgery. If a rat does open her incision, it can easily be closed again with staples or Michel wound clips without the need for anesthetic or sedation. Putting in staples or clips only causes minor discomfort.

An Elizabethan collar, commonly used in dogs and cats, should only be used in rats to prevent scratching of the eye or ear in severe situations. It should not be used to protect a surgical incision because it prevents the rat from grooming her face and can also prevent eating, drinking, and walking.

A body cast or cervical collar works by preventing the rat from bending her neck or body to reach the incision. The body cast may also directly protect the incision, but it must still prevent the rat from bending. If the rat can reach the cast with her teeth she will be able to chew it off. The body cast is more effective than the cervical collar and should be used if the incision is in the lower abdomen or groin area, but it is also much more restrictive than the cervical collar. The rat will still be able to walk but won’t be able to sit up. If the incision is under the armpit or on the shoulders you can use a cervical collar.

Rats who chew open their incision usually do so the first night after the surgery, so it’s especially important to check the incision the next morning. If the incision has been opened, call your vet to see about having it closed again. This can be done easily with staples or clips without sedation or anesthesia. Or, if the incision is less than 1½" long, you can just leave it open to heal on its own. Rat skin heals very quickly and it doesn’t matter if the skin gapes open, it will still heal fine. In an emergency, you can clean up a large open incision and close it with Super Glue. Just clean the edges of the wound so they are dry, dab on the glue and press the edges together. Be careful not to glue your fingers to the incision!

Even if the incision is protected in some way, some rats are masters at chewing open their incision no matter what. For this reason, I recommend that all post-surgical rats be kept in a cage with only shredded paper or rags—no litter or bedding with small particles—until the incision is healed to prevent possible contamination.

The Body Cast

Adhesive bandage tape makes the most secure and comfortable body cast. A stretchy bandage must be wrapped over the shoulders and between the arms to keep the rat from wiggling out of it, and this actually restricts the rat’s movement more than the adhesive tape.

If the incision will be covered by the cast, cover it with gauze. Wrap several layers of ¾" adhesive tape around the rat’s middle, between the front and back legs, sticking the tape directly to the fur, otherwise they just walk right out of it. The cast should not restrict the rat’s breathing, but it must be snug enough so the rat won’t get her back feet caught in it. Apply 3-5 layers of tape to make the cast stiff.

The cast will last at least 2 to 5 days, long enough to protect the incision during the critical healing period. When the incision is mostly healed, if your rat hasn’t gotten out of the cast herself, you can remove it by cutting the tape and putting vegetable oil on the inside to help dissolve the adhesive. (Thanks to Joe Falcone and Karri Kaiser for this idea.)

The Cervical Collar

A cervical collar is not as effective as a body cast, but it is less restrictive. It works well for incisions in the armpit, shoulder or back area. Simply wrap enough layers of ½" adhesive tape snugly around the rat’s neck to make a collar stiff enough to prevent the rat from bending her neck.

Spays and Neuters

A rat spay is similar to a cat spay and should cost about the same. If the surgeon is experienced complications are rare, although there is always a small risk due to the anesthetic or bleeding. I recommend a full ovariohysterectomy rather than just an ovariectomy because uterine bleeding, caused by mycoplasma, that can be fatal is a common problem in older females.

When scheduling a rat to be spayed, it’s best to do it 2-3 days after she is in heat. When in heat, the uterus is blood engorged, and although a spay can be done at this time, it’s best done when the rat is not in heat. A pregnant rat can also be spayed, but occasionally a pregnancy (or false pregnancy) will change a rat’s behavior and make her aggressive or obsessive. If this happens, this change may persist after the surgery, so in this case it’s better not to spay while she is pregnant.

Neutering a male rat is more complicated than neutering a dog or cat. A rat neuter seems to cause more pain and discomfort than a rat spay if it is done through the scrotum. Rodents have an open inguinal canal, which allows them to draw their testicles up inside the body cavity. This means that a neuter can be done like a spay, avoiding the sensitive scrotum.

If a rat neuter is done through the scrotum, it should be done using a closed method and sterile surgery to prevent peritonitis. The scrotal sac should be sutured or ligated separately from the skin. A fairly common complication is a scrotal abscess, which usually occurs 2-6 weeks after the surgery. The chances of this might be reduced if the large amount of fat associated with the testicles is removed. Performing the neuter through the abdomen like a spay avoids the possibility of a scrotal abscess and is highly recommended. An inguinal hernia is not likely because the remaining fat will block the inguinal canal. Neutering is easier on both surgeon and rat when done as young as possible, even at 4 weeks, but it can be done at any age. A neutered male may continue to be fertile for 3 weeks after the surgery.

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