There are times that you may have to consider taking your rat to a veterinarian to have surgery, maybe to remove a tumor or cancerous growth. The first thing to consider is if your rat is healthy enough for surgery. If your rat is over-weight, has breathing problems, or is in any other way in bad health, surgery may not be possible. You should discuss this with your surgeon before hand. Finding a Veterinarian that has experience with small animals and has done this particular surgery before is a must. Not all Vets have experience with "Exotics" and therefore finding one who does is a top priority.
It is important to discuss the methods they will use for surgery. What kind of anesthesia will they use? Gas is the most common type used now because finding a vein in a small rat is not likely and gas is much easier to administer. Will they prescribe a post operative pain killer for your rat? It is important to make sure they are willing to give you a post operative analgesic, the pain medicine they give during surgery will likely wear off a few hours after surgery and there's no need for them to be in pain while they heal.
Unlike you and I, rats do not need to fast twelve hours before surgery. They are unable to vomit and can eat right up until they go in for surgery. After surgery they will most likely want some water and you should make sure you are there to help them get at the water bottle if they need extra help. The Veterinarian hospital staff is going to be busy and no one will give your little fuzzy buddy the tender loving care that you yourself will. Make sure they are being kept warm and have food around they can eat.
Make sure to ask what kind of stitches they have used to close the wound. Most Vets will use subcuticular dissolvable stitches which are small stitches under the skin that make it harder for the rat to chew off. Most wounds will heal fast as long as the rat leaves them alone. For larger wounds a vet may have to put in staples or other types of stitches. If your rat starts chewing on them, the vet may tape a piece of gauze around the wound and then use cast material to make it harder for the rat to open the wound back up. Most rats won't bother too much with the wounds and they will heal quickly.
Once you get your rat home you will want to keep them separated from any other cage mates for at least two days. This is just so they can heal before their cage mates start sniffing at the wound or accidentally hurt them while playing. Most rats are smart and will curl up next to a cage mate that's not feeling good.
While you have your rat in its own cage you have to make sure to keep him warm. It's easiest to do this using a single level glass cage. Putting a heating pad on the low setting, that's covered with a towel, under the tank will keep the cage warm. Put the heating pad under only half of the tank so your rat can choose whether they want to lay over it. You rat will be sleeping and may just want to curl up and sleep for a while after coming home, this is perfectly normal. You should wake your rat up every two hours and offer him some water either from his water bottle or from a dropper to make sure he doesn't get dehydrated. Offering some baby food or soft food will also help him feel better and help him heal faster. Mixing any powdered or liquid medicines the vet gives you into a small amount of yogurt or baby food will make it easier for your rat to take his medicine. While also making sure he gets some food.
If your rat become lethargic or won't eat or drink you should take them back to the vets office right away. This is a sign of dehydration and a rat can die from this rather quickly. Your vet can give them an injection to get them hydrated again. If you see any redness or swelling around the wound, this may be a sign of infection and you should take your rat back to the Vets office right away.
The most important thing to remember is to be there for your rat. Hold them, give them all the attention they want, hand feed them if necessary and give them lots of love.