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Updated: Aug 10, 2026
Establishment of a Clinic-based Biorepository
Published on: May 29, 2017
Complications Associated with Mohs Micrographic Surgery: Data from the Nationwide Prospective Cohort REGESMOHS
Verónica Ruiz-Salas1,2, Onofre Sanmartin-Jiménez3, Joan R Garcés1,2
1Hospital de la Santa Creu i Sant Pau, Barcelona, Spain.
Background:
Large prospective studies on the safety of Mohs micrographic (MMS) surgery are scarce, and most focus on a single type of surgical adverse event. Mid-term scar alterations and functional loss have not been described.
Objectives:
To describe the risk of MMS complications and the risk factors for them.
Methods:
A nationwide prospective cohort collected all adverse events on consecutive patients in 22 specialised centres. We used multilevel mixed-effects logistic regression to find out factors associated with adverse events.
Results:
5,017 patients were included, with 14,421 patient-years of follow-up. 7.0% had some perioperative morbidity and 6.5% had mid-term and scar-related complications. The overall risk of complications was mainly associated with use of antiaggregant/anticoagulant and larger tumours, affecting deeper structures, not reaching a tumour-free border, and requiring complex repair. Age and outpatient setting were not linked to the incidence of adverse events. Risk factors for haemorrhage (0.9%) were therapy with antiaggregant/anticoagulants, tumour size, duration of surgery, and unfinished surgery. Wound necrosis (1.9%) and dehiscence (1.0%) were associated with larger defects and complex closures. Immunosuppression was only associated with an increased risk of necrosis. Surgeries reaching deeper structures, larger tumours and previous surgical treatments were associated with wound infection (0.9%). Aesthetic scar alterations (5.4%) were more common in younger patients, with larger tumours, in H-area, and in flap and complex closures. Risk factors for functional scar alterations (1.7%) were the need for general anaesthesia, larger tumours that had received previous surgery, and flaps or complex closures.
Conclusions:
MMS shows a low risk of complications. Most of the risk factors for complications were related to tumour size and depth, and the resulting need for complex surgery. Antiaggregant/anticoagulant intake was associated with a small increase in the risk of haemorrhage, that probably does not justify withdrawal. Age and outpatient setting were not linked to the risk of adverse events.
Insights
Mohs micrographic surgery (MMS) has a low complication rate. Factors like tumor size and depth, and complex repairs increase risk, while age and outpatient setting do not impact adverse events.
Area of Science:
- Dermatology
- Surgical Oncology
- Plastic Surgery
Background:
- Prospective studies on Mohs micrographic surgery (MMS) safety are limited.
- Previous research often focused on single adverse events, neglecting mid-term outcomes like scar alterations and functional loss.
Purpose of the Study:
- To assess the overall risk of complications following Mohs micrographic surgery.
- To identify specific risk factors associated with adverse events in MMS.
Main Methods:
- A nationwide prospective cohort study was conducted across 22 specialized centers.
- Multilevel mixed-effects logistic regression analyzed factors linked to adverse events in 5,017 patients.
Main Results:
- Overall complication rate was low, with 7.0% perioperative morbidity and 6.5% mid-term/scar complications.
- Risk factors included antiaggregant/anticoagulant use, larger/deeper tumors, incomplete tumor removal, and complex repairs.
- Hemorrhage (0.9%), necrosis (1.9%), dehiscence (1.0%), and scar alterations (5.4% aesthetic, 1.7% functional) were analyzed.
Conclusions:
- Mohs micrographic surgery demonstrates a favorable safety profile with a low incidence of complications.
- Tumor characteristics (size, depth) and the complexity of surgical repair are primary drivers of risk.
- While antiaggregant/anticoagulant use slightly increases hemorrhage risk, it may not warrant discontinuation; age and outpatient setting were not significant risk factors.
