Mohs surgery typically involves five steps:
1. Anesthesia
Mohs surgery is performed using local anesthesia, which involves less risk than general anesthesia. At the beginning of the procedure, the area of interest is cleaned, then numbed with a mixture of lidocaine and epinephrine. While there may be some slight stinging or burning associated with the injection itself, the area around the injection quickly numbs, making the rest of the surgery painless.
2. Tissue Removal
The skin cancer is first debulked, allowing the physician to explore how deep the cancer penetrates beneath the skin. A thin layer of the surrounding tissue is then removed and a dressing is applied over the wound.
3. Tissue Mapping and Examination
The layer of tissue that was removed is then labeled, mapped, processed, and mounted on a slide. All of this is done at an on-site laboratory. Creating a finished slide with the tissue specimen is the most time consuming part of the Mohs surgery day, taking between 1-2 hours for each stage. The slides are then examined under the microscope by the Mohs surgeon at the on-site laboratory, and the results are interpreted. Areas where skin cancer still remains is mapped accordingly.
4. Additional Tissue Removal
If the first layer displays residual skin cancer, another small layer of skin is removed from the cancerous areas only. This sample is again labeled, mapped, processed, and mounted on a slide for examination under the microscope. This process is repeated until all tissue removed is found to be cancer-free, at which point the excisional wound is prepared for closure.
5. Reconstruction
With the all of the cancer removed, the wound is then closed. The science of wound closure is complex and involves a profound knowledge of tissue anatomy and movement, balanced by knowledge of aesthetic outcomes. Based on the size and location of the wound, closure may involve simple side-to-side closures, flaps, or grafts. Sometimes, the wound is left open to heal by itself.
