Highlights from the Literature 2

Characteristics of Lower Extremity Infection Rates Following Mohs Micrographic Surgery

Niklinska EB, Hicks A, Wheless L, Hanlon A. Characteristics of Lower Extremity Infection Rates Following Mohs Micrographic Surgery. Dermatol Surg. 2021; 47(21): 1547-50.  

by Charlene Lam, MD, MPH, FACMS

Even though surgical site infection (SSI) is the most common complication of Mohs surgery, the overall reported infection incidence is very low (0.4 – 2.5%).¹  However, compared with other body sites, the lower extremities portend a much higher risk of infection.

 In this retrospective review at Vanderbilt, Niklinska et al. reviewed all lower extremity Mohs cases from 2011 to 2016 and tracked patient follow-up and clinical communications for 1-month post-surgery.² SSI was diagnosed with positive culture or clinical evidence of infection including intense erythema, purulent drainage, edema, and pain. Forty-six of the 620 (7.4%) cases met criteria for SSI, which was consistent with previous studies.³ Wounds closed by flaps/grafts had a significantly higher rate of infection (35%) compared to those closed by linear repair (7.7%) or allowed to heal by second intent (5.5%, p<.001).  Larger wounds had a higher risk of infection, also confirming previous studies.⁴ Using stratified analysis, they found that large wounds (> 4cm2) allowed to heal by second intent had a lower infection incidence than those closed with a flap or graft.

Interestingly, 48% of the cohort received either a preoperative (92/620), post-operative (208/620) antibiotic or both (19/620). Cephalexin was the most used antibiotic (186/620). However, this prophylactic practice did not seem to make a statistical difference in infection rates. The authors conclude that more multicenter, prospective studies are needed to determine the effectiveness of antibiotic prophylaxis on SSI. 

Overall, this study reaffirms the challenges we encounter in lower extremity Mohs surgery. With evolving antibiotic prophylaxis guidelines and variations in practice patterns, this single center, retrospective review study characterizes the factors associated with SSI in the lower extremities that will help define future studies.

References:

1. Alam M, Ibrahim O, Nodzenski M, Strasswimmer JM, et al. Adverse events associated with Mohs micrographic surgery: multicenter prospective cohort study of 20,821 cases at 23 centers. JAMA Dermatol 2013;149:1378–85.
2. Niklinska EB, Hicks A, Wheless L, Hanlon A. Characteristics of Lower Extremity Infection Rates Following Mohs Micrographic Surgery.  Dermatol Surg 2021; 47(21): 1547-50.   
3. 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(8):19–27.
4. Liu X, Sprengers M, Nelemans PJ, Mosterd K, et al. Risk factors for surgical site infections in dermatological surgery. Acta Derm Venereol 2018;98:246–50.