A surgeon’s primary intention is to reduce secondary infection
By Ashley Decker, MD, FAAD, and Naomi Lawrence, MD, FAAD
Feb. 8, 2023
Vol. 5, No. 6
A commonly held belief in dermatologic surgery is that second intention wounds have a lower risk of surgical site infection (SSI) than primary closures and flaps. However, our clinical experience suggested that second intention wounds, especially on the lower extremity (LE), had higher infection rates. A deep search into the literature to determine the origin of this old adage identified minimal supportive evidence. The available studies were small, assessed a limited number of wound locations, and did not directly compare the infection rate for sutured versus second intention wounds. (1, 2, 3)
To address these knowledge gaps, we conducted the largest published retrospective cohort study to examine the rate of postsurgical infections after skin cancer removal by Mohs micrographic surgery (MMS) or wide local excision (WLE). Five thousand six hundred seventy-nine MMS or WLE performed by a single surgeon over a 5-years were included in the analysis. Eighty-two percent (n = 4,655) were sutured and 18% (n = 1,024) healed by second intention.
Wounds were stratified by closure type, location, and associated organisms. Infection was diagnosed by a positive wound culture. The overall infection rate was 3.9%. Second intention wounds were associated with a significantly higher risk of infection compared with sutured wounds (6.8% versus 3.2%). The lower extremity (LE) had the highest risk of infection overall (10.5%) with no difference in closure type. Staphylococcus aureus and Pseudomonas spp. were the most common cultured species across all closure types. The results confirmed our clinical observation.
Interestingly, in 285 wounds with a clinically diagnosed infection in which a wound culture was performed, 66 (23%) of cultures did not identify a pathogenic organism (41 [22%] sutured, 25 [26%] second intention). This highlights an important point, that early signs of infection can mimic normal healing (mild erythema, edema, and tenderness). In our experience, constant, throbbing pain not alleviated with pain medications is a common early symptom of infection, even in the absence of other clinical findings. We concluded that the LE may be particularly prone to SSI, regardless of the closure approach, owing to wound contamination from S. Aureus colonization in the groin and less robust hygiene practices. (4)
This study has changed the way we think about SSIs in our practice, including how we counsel patients, especially those with second intention wounds. The role of prophylactic oral antibiotics is unclear and it is important that as field we are good stewards of antibiotic use. Indeed, in a study of 816 MMS cases 151 were prescribed antibiotic prophylaxis (18.5%). Of 467 cases with follow-up, 16 (3.4%) developed SSI. Infection rates were higher in subjects prescribed prophylaxis, but propensity adjustment reduced this effect. Adjusted odds of infection were 1.47-fold higher in subjects prescribed antibiotics and not statistically significant. (5)
The proper role of topical decolonization, especially for anticipated second intention wounds or LE location, needs to be properly defined. Certain populations are clearly at risk. For example, MRSA colonization was detected in 13%-15% of HIV-infected participants (n=600, 98% male) at baseline, 6 months, and 12 months. MRSA colonization was detected in the nares only (41%), groin only (21%), and at both sites (38%). Over a median of 2.1 years of follow-up, 29 MRSA clinical infections occurred in 25 participants. The authors suggested that MRSA prevention strategies that effectively prevent or eliminate groin colonization are likely necessary to reduce clinical infections in this population. (6) In all likelihood, this holds true for the non-HIV population as well.
To provide this important information, we are conducting a multicenter randomized clinical trial to examine the potential benefit with topical decolonization with intranasal mupirocin and hibiclens wash prior to surgery.
Point to Remember: Surgical site infections appear most commonly on the lower extremities. Data suggests that this may be more common in a wound healing by secondary intention. We must recognize patients at risk. More studies are necessary to determine the precise role of antibiotic prophylaxis to prevent these infections.
Our editor’s viewpoint
Warren R. Heymann, MD, FAAD
Post-operative wound infections are not just a problem for Mohs surgeons — they are paramount importance to any dermatologist performing any surgical procedure. In a commentary accompanying the research of Schimmel et al (4), Soon states: “Postoperative infection after dermatologic surgery is uncommon, but nonetheless significant in its association with decreased patient satisfaction, poorer outcome, and increased cost of care.” (7)
Predicting who may be at risk, and the type of wound that may be subject to secondary infection, is essential in targeting patients for whom antibiotic prophylaxis is appropriate. Given the vital importance of antibiotic stewardship to prevent ever-increasing antibiotic resistance, ongoing research is essential to establish the proper guidelines.
Dixon AJ, Dixon MP, Askew DA, Wilkinson D. Prospective study of wound infections in dermatologic surgery in the absence of prophylactic antibiotics. Dermatol Surg 2006;32:819–27.
Rogers HD, Desciak EB, Marcus RP, Wang S, et al. Prospective study of wound infections in Mohs micrographic surgery using clean surgical technique in the absence of prophylactic antibiotics. J Am Acad Dermatol 2010;63:842–51.
Futoryan T, Grande D. Postoperative wound infection rates in dermatologic surgery. Dermatol Surg 1995;21:509–14.
Schimmel J, Belcher M, Vieira C, Lawrence N, Decker A. Incidence of Surgical Site Infections in Second Intention Healing After Dermatologic Surgery. Dermatol Surg. 2020 Dec;46(12):1492-1497. doi: 10.1097/DSS.0000000000002409. PMID: 32483093.
Levin EC, Chow C, Makhzoumi Z, Jin C, et al. Association of postoperative antibiotics with surgical site infection in Mohs micrographic surgery. Dermatol Surg 2019;45:52–7.
Peters PJ, Brooks JT, McAllister SK, Limbago B, et al. Methicillin-resistant staphylococcus aureus colonization of the groin and risk for clinical infection among HIV-infected adults. Emerg Infect Dis 2013;19:623–9.
Soon SL. Commentary on Incidence of Surgical Site Infections in Second Intention Healing After Dermatologic Surgery. Dermatol Surg. 2020 Dec;46(12):1498-1499. doi: 10.1097/DSS.0000000000002422. PMID: 32371780.
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