Adverse events associated with mohs micrographic surgery: Multicenter Prospective Cohort Study of 20 821 Casesat 23 Centers

Importance Detailed information regarding perioperative risk and adverse events associated with Mohs micrographic surgery (MMS) can guide clinical management. Much of the data regarding complications ofMMSare anecdotal or report findings from single centers or single events. Objectives To quantify adverse events associated with MMS and detect differences relevant to safety. Design, Setting, And Participants Multicenter prospective inception cohort study of 21 private and 2 institutional US ambulatory referral centers for MMS. Participants were a consecutive sample of patients presenting with MMS for 35 weeks at each center, with staggered start times. Exposure Mohs micrographic surgery. Main Outcomes And Measures Intraoperative and postoperative minor and serious adverse events. Results Among 20 821 MMS procedures, 149 adverse events (0.72%), including 4 serious events (0.02%), and no deaths were reported. Common adverse events reported were infections (61.1%), dehiscence and partial or full necrosis (20.1%), and bleeding and hematoma (15.4%). Most bleeding and wound-healing complications occurred in patients receiving anticoagulation therapy. Use of some antiseptics and antibiotics and sterile gloves during MMS were associated with modest reduction of risk for adverse events. Conclusions And Relevance Mohs micrographic surgery is safe, with a very lowrate of adverse events, an exceedingly low rate of serious adverse events, and an undetectable mortality rate.Commoncomplications include infections, followed by impaired wound healing and bleeding. Bleeding and wound-healing issues are often associated with preexisting anticoagulation therapy, which is nonetheless managed safely duringMMS.We are not certain whether the small effects seen with the use of sterile gloves and antiseptics and antibiotics are clinically significant and whether wide-scale practice changeswould be cost-effective given the small risk reductions.