Prevalence of wound complications following Mohs micrographic surgery (MMS): a cross-sectional study of 1000 patients undergoing MMS and wound repair in a UK teaching hospital.

Background: Mohs micrographic surgery (MMS) for nonmelanoma skin cancer is often quoted as having an excellent safety profile.

Aim: To determine the complication rate of patients undergoing MMS in a large UK Mohs unit and subdivide complication rates into mild/intermediate and major, and to identify potential risk factors necessitating a clinical intervention.

Methods: This was a single-centre, cross-sectional study of 1000 consecutive cases of MMS performed with in-house repair. Notes from the postsurgical dressing clinics were reviewed at Visit 1 (Days 7-14) and Visit 2 (approximately Week 6). Based upon the intervention required and effect on cosmetic/functional outcome, complications were classified as minor, intermediate or major. Logistic regression modelling was used to identify risk factors associated with a complication that needed a clinical intervention (i.e. intermediate or major).

Results: In total, 1000 Mohs surgeries were performed on 803 patients, resulting in 1067 excisions. Complication rates in our cohort were low (minor 3.6%, intermediate 3.1% and major 0.8%) Potential risk factors for developing a complication included skin graft (unadjusted OR = 4.89, 95% CI 1.93-12.39; fully adjusted OR = 7.13, 95% CI 2.26-22.45) and patients undergoing surgery on the forehead (unadjusted OR = 3.32, 95% CI 0.95-11.58; fully adjusted OR = 5.34, 95% CI 1.40-20.42). Patients whose wounds were allowed to heal by secondary intention healing (6.8%) exhibited no complications.

Conclusion: We advocate that patients should be informed during the consent procedure that less than 1 in every 100 patients (0.75%) undergoing MMS will have a serious adverse event (major complication) affecting their cosmetic or functional outcome.