A friend of mine called yesterday to ask me about his cat’s surgery site. He had gone to a veterinary clinic to have her spay surgery done last week and there now seemed to be a problem. The incision was opening up and foul smelling pus was oozing out. What to do was his question.
An infected surgery site is unfortunately not an uncommon occurrence in veterinary medicine. Research tells us that approximately 5% of dogs and cats may develop infections after a surgery, regardless of the kind. When we focus in on sterile uncomplicated surgeries like a spay surgery, the risk should be less than 2.5%.The reason for this relatively high level of infection is the habits of pets themselves. Cats are particularly good at contortions and are able to lick virtually every area of their bodies. That velvet tongue that is so gentle when licking your hand, can become a rasp if they want it to. The first thing a cat likes to do after surgery is to “clean” the surgery site. As if it wasn’t clean enough already! This grooming will carry saliva onto the incision and greatly increases the risk of infection. For this reason I always advise that an Elizabethan collar (aka “cone of shame”) be used after surgery. It can prevent a host of problems! Unfortunately, this was not recommended by his vet clinic. She had been licking and now it was infected. In addition to preventing licking of the surgical site, using sutures (stitches) that are buried under the skin greatly reduces the risk of that saliva from having an easy passage to track down to get under the skin. The technique called “sub-cuticular” or “intra-dermal” closure has the stitches on the under side of the skin and a buried knot at the end should leave no visible sutures on the skin. This is not only less likely to get infected, it also is much more comfortable for the cat.
As mentioned above, wound infections can occur despite our best efforts but just because it looks like it is opening up, it doesn’t mean that the abdominal wall is going to open up! After surgery, the body wall is closed separately from the skin layer so the inner layer may be just fine, despite the look of the skin. Having said that, it does require skill to assess and a veterinarian is the best person to determine if the wound can be treated as an open wound or whether surgery will need to be repeated and sutures replaced.
Re-closing a wound is somewhat controversial. It’s not as simple as placing a few new sutures in the skin! A wound that is fresh and just has the presence of bacteria, can be cleaned and flushed and re-closed with in 8 hours of the wound being made. Any longer than this golden period, gives the bacteria a chance to “dig in” and the wound is no longer classed as a “contaminated wound” but an infected wound. Once infection has set in, the bacteria have started to invade the tissues and closing the wound again traps them inside the wound and can lead to an abscess. An infected wound must first be treated with antibiotics, flushes and “debriding” that is, the surgical removal of all damaged and infected tissue – basically surgically removing the old incision and starting over again. However, if the wound is relatively small and easily managed, it can be treated with antibiotics and surface washes with saline until a layer of healing tissue covers the wound. This layer of tissue is called granulation tissue and it usually covers the wound surfaces within a week. Once this layer has covered the wound, antibiotics are not usually indicated, just saline washes and possibly dressings depending on the location of the wound. The edges of the wound are gradually drawn together
by the healing process and most often the scar that remains is minimal. However, all of these are less than the ideal of primary healing of the skin with the sutures holding the fresh wound edges close together. Interestingly, it is the same process of healing with or without sutures, the only difference being the amount of time to heal and amount of scar tissue left at the site after all healing is done.
All that to say, when in doubt bring your pet to a veterinarian who will assess your pet and hopefully prescribe the correct mode of treatment. Some of the factors to be considered are; weakened immune system, old age, poor physical condition, malnutrition, systemic disease, drug therapy, number of bacteria, kind of bacteria, time since contamination, presence of dead or damaged tissue, haematoma or blood clots, pockets of open space under skin, reduced blood supply or foreign material in the wound. I would love to be able to report that you will always get the right treatment every time but sadly, that is not always the case. Never be shy to ask for a second opinion or for alternative treatments.