Surgical Wounds
Section editor:
Surgical wounds are those created during a medical procedure. They may consist of incisions, punctures, or excisions.1 Ideally, the surgeon will close the surgical wound primarily at the end of a procedure with sutures or staples, and the surgical wound will close through the typical stages of wound healing. However, there are instances when primary closure is not desired or possible, adding to their complexity.
Classifying Surgical Wounds
Classifications of surgical wounds in the preoperative time frame can help medical teams better understand and stratify for risk of surgical site infection. If events transpire intraoperatively that change this classification, this event should also be documented.
The Centers for Disease Control and Prevention (CDC) created the often used system below as part of preprocedural surveillance:1-3
Class 1/Clean. Usually closed primarily, not infected, and not involving significant inflammation, these wounds are also not usually in areas of higher microorganism colonization—meaning, they are not typically in the respiratory, genital, urinary, or alimentary tracts.1,3 Any drain system used must be considered closed. This class of surgical wounds usually carries a less than 2% infection rate.3
Class 2/Clean-Contaminated. These types of surgical wounds may involve those higher areas of colonization discussed above, but do not typically have additional risk of unusual or unexpected contamination. Teams usually carefully monitor these wounds under planned and controlled conditions.1,3 Infection risk in this class is typically less than 10%.3
Class 3/Contaminated. In these cases, the surgical wound is fresh and open, with assumed contamination. Trauma, acute inflammation (without purulence), errors in sterile technique, unintentional wound creation or gastrointestinal fluid leakage into the wound can fall under this class.1,3 Infection risk for class 3 surgical wounds is at least 13–20%.3
Class 4/Dirty-Infected. These wounds most commonly result from microorganisms present in perforated viscera or in the operative field.1,3 The contamination may already be present at the time of surgery and may later result in postoperative infection.3 These wounds carry the highest risk for infection, at around 40%.3
The Role of Antibiotics in Surgical Wounds
Pre- and/or postoperative antibiotics may be indicated for surgical wounds, depending on the circumstances. For example, Dirty-Infected or Contaminated procedures do not usually necessitate preoperative antibiotic prophylaxis, since they likely require specific, targeted postoperative antibiotic therapy.4 Additionally, the surgeon may wish to hold preoperative antibiotics when indicated to aid in a more accurate deep wound or tissue culture. Each facility typically has established protocols for when and how to choose preoperative antibiotics for surgical wounds.
Understanding the risk stratification for each type of surgical wound may also allow the surgical and postoperative teams to make postop choices that align with SSI prevention tailored to each respective wound class. For instance, a clean, primarily closed surgical wound from a lower-risk procedure is less likely to necessitate specialized intervention.
How are Surgical Wounds Closed?
Primary closure occurs when all tissue and skin layers are reapproximated, but closure by secondary intent may be chosen when deep layers are closed, but there is not an ability to close or reapproximate more superficial skin and tissue. Tertiary intent, or delayed primary closure, is occurs when the surgical wound is intentionally left open to allow for drainage, contamination control, or to prepare for a future procedure.5
Conclusion
Surgical wounds can be straightforward or complex, thus commanding thoughtful evaluation and consideration in wound healing. Careful assessment of risk, along with the circumstances of the case in question, can guide providers in determining challenges to healing and best ways to prevent infection.
References
1. Centers for Disease Control and Prevention. National Healthcare Safety Network. Surgical Site Infection Event (SSI). Published January 2023. Accessed June 29, 2023.: https://www.cdc.gov/nhsn/pdfs/pscmanual/9pscssicurrent.pdf.
2. Onyekwelu I, Yakkanti R, Protzer L, Pinkston CM, Tucker C, Seligson D. Surgical wound classification and surgical site infections in the orthopaedic patient. J Am Acad Orthop Surg Glob Res Rev. 2017:1(3):e022. doi: 10.5435/JAAOSGlobal-D-17-00022.
3. American College of Surgeons. Wound Home Skills Kit: Surgical Wounds. Accessed June 29, 2023. https://www.facs.org/media/zr5dimjk/wound_surgical.pdf.
4. Zabaglo M, Sharman T. Postoperative wound infection. In: StatPearls [Internet]. StatPearls Publishing; Updated September 19, 2022. Accessed January 2023. https://www.ncbi.nlm.nih.gov/books/NBK560533/
5. Berríos-Torres SI, Umscheid CA, Bratzler DW, et al. Centers for Disease Control and Prevention Guideline for the Prevention of Surgical Site Infection, 2017. JAMA Surg. 2017;152(8):784–791. doi:10.1001/jamasurg.2017.0904
