The Surgical Infection Paradox

The Paradox: Cutting skin increases the chances for infection.  Closing skin increases the chances for infection.

The integument (i.e., the skin and the epithelium lining the digestive and urinary tracts) is our immune system.  When the integument is injured, microorganisms have the opportunity to invade the interstitium.  This invasion triggers a response by the so-called immune system, which really functions as a border patrol.  Several of such invasions can be managed by the local defenses, which are various types of white blood cells resident in the tissues.

For example, a paper cut on the finger is an opportunity for organisms to invade.  Because the total number of organisms that actually invade in a paper cut are usually very meager when people are washing their hands frequently, the local defenses can handle the invasion without even demonstrating the signs of infection.  When a higher concentration of bacteria get into the tissue, such as a cut with a dirty and highly contaminated knife, the number of organisms overwhelm the local defenses.  As a result, a call for backup occurs, and white blood cells of various types are called into the fray, producing the typical signs of an inflammatory responses (redness, pain, swelling, warmth, etc.) which we recognize as an infection.

When we surgeons incise skin, we enable the potential for bacterial invasion.  If the amount of contamination is excessive, we will trap those organisms in tissue at the time we close the wound.  In such cases, it has been demonstrated that timely administration of antibiotics immediately before and during the contamination will reduce the rate of surgical infections observed.  Prolonged antibiotics following wound closure have been shown to offer no benefit, but rather increase costs and the potential for resistant strains to emerge.  Despite extensive data regarding the necessarily brief course of antibiotic effectiveness as prophylaxis (and national initiatives promoting antibiotic discontinuation by 24 hours postoperatively), many clinicians still feel compelled to continue prophylactic perioperative antibiotics for days and days following surgery.

The paradigm shift in medicine is to understand the biological nature of surgical wound infections and use antibiotics in a targeted strike against the invaders.