Surgical Site Infections
Your skin is a natural barrier against infection, so any surgery that causes a break in the skin can lead to a postoperative infection. Doctors call these infections surgical site infections (SSIs) because they occur on the part of the body where the surgery took place. If you have surgery, the chances of developing an SSI are about 1 to 3 percent.
Types of SSIs
An SSI typically occurs within 30 days after surgery. The CDC describes three types of surgical site infections:
Superficial incisional SSI. This infection occurs just in the area of the skin where the surgical incision was made.
Deep incisional SSI. This infection occurs beneath the incision area in muscle tissue and in fascia, the tissue surrounding the muscles.
Organ or space SSI. This type of infection can be in any area of the body other than skin, muscle, and fascia that was involved in the surgery, such as a body organ or a space between organs.
Signs and symptoms of SSIs
Any SSI may cause redness, delayed healing, fever, pain, tenderness, warmth, or swelling. These are the additional signs and symptoms for specific types of SSI:
A superficial incisional SSI may produce pus, which doctors call "purulent discharge," from the wound site. Samples of the pus may be grown in a culture to find out the types of germs that are causing the infection.
A deep incisional SSI may also produce pus. The wound site may reopen on its own, or a surgeon may reopen the wound and find purulent discharge inside the wound.
An organ or space SSI may show a discharge of pus coming from a drain placed through the skin into a body space or organ. A collection of purulent discharge called an abscess is an enclosed area of pus and disintegrating tissue surrounded by inflammation. An abscess may be seen when the surgeon reopens the wound or by special X-ray studies.
Causes and risk factors of SSIs
Infections after surgery are caused by germs called microorganisms. The most common of these include the bacteria Staphylococcus, Streptococcus, and Pseudomonas. Microorganisms can infect a surgical wound through various forms of contact, such as from the touch of a contaminated caregiver or surgical instrument, through microorganisms in the air, or through microorganisms that are already on or in your body and then spread into the wound.
The degree of risk for an SSI is linked to the type of surgical wound you have. Surgical wounds can be classified in this way:
Clean wounds. These are not inflamed or contaminated and do not involve operating on an internal organ; the risk for an SSI in this type of wound is less than 2 percent.
Clean-contaminated wounds. These have no evidence of infection at the time of surgery, but do involve operating on an internal organ; the risk for SSI is less than 10 percent.
Contaminated wounds. These involve operating on an internal organ with a spilling of contents from the organ into the wound; the risk for SSI is 13 to 20 percent.
Dirty wounds. These are wounds in which a known infection is present at the time of the surgery; the risk for SSI is about 40 percent.
These are other risk factors for SSIs:
Surgery that lasts more than two hours
Having other medical problems or diseases
Being an elderly adult
Having a weakened immune system
Having emergency surgery
Having abdominal surgery
Helping prevent SSIs
If you are having surgery, ask your doctor what you can do to reduce your risk for a surgical site infection. It's important to stop smoking before surgery and to tell your surgical team about your medical history, especially if you have diabetes or another chronic illness. Also, avoid shaving in the skin area that the surgeon is planning to operate through.
No matter how curious they are, loved ones should not touch your wound or surgical site. Carefully follow your doctor's instructions about wound care after surgery. Call your doctor if you develop a fever or pus, redness, heat, pain and/or tenderness near the wound or any other signs or symptoms of a surgical site infection.
Most SSIs can be treated with antibiotic medications. Sometimes additional surgery or procedures may be required to treat the SSI. During recovery, make sure that friends and family members wash their hands before and after they enter your room—and make sure doctors, nurses, and other caregivers wash their hands, too.