What Happens On the Day of Mohs Surgery?

Mohs surgery typically takes at least several hours; however, due to the nature of this technique, ie, checking each stage under the microscope in real-time, we cannot predict the exact duration of surgery. Please plan to spend the day with us and do not make other appointments or meetings on the day of surgery. As a general rule-of-thumb, about half of skin cancers are cleared after 1 or 2 stages.

Before surgery, please eat normally and take all your regular medications. There is no need to fast. If you take medications during the day, please bring them with you. Please shower/bathe the morning of surgery to ensure a clean site and as you will not be able to for 24 hours after surgery (48 hours if you take a blood thinner).

On the day of surgery, you will meet the nurses and surgeon who will verify the surgical site with you and discuss any questions and concerns.

Step 1: Anesthesia

The tumor site is numbed with local infiltration of anesthesia. This anesthesia lasts for 1-4 hours and will be added throughout the day as needed. You will remain awake for the entire duration of surgery.

Step 2: Removal of tumor

Once the skin is numbed, the first stage or “layer” of tissue is removed. This step takes 10-20 minutes.

Step 3: Evaluating the tissue

The removed tissue is then inked and a color-coded map is created to precisely guide the location of the tumor. A laboratory technician processes the tissue and embeds it onto a microscope slide. The surgeon then examines the entire tissue layer for evidence of microscopic tumor. This step takes approximately 1 hour.

Step 4: Additional stages

If tumor is seen under the microscope in step 3, the surgeon will remove more tissue at that specific area and repeat the process of embedding the tumor and examining under the microscope. Each additional stage will take approximately 1 hour.

Step 5: Reconstruction

Once the skin cancer is completely removed, reconstruction options will be customized to preserve function and maximize cosmetic outcome.

The best method of repairing the wound cannot be determined until the skin cancer is removed, but possible options include:

  • Healing by spontaneous granulation (natural healing)
  • Closing the wound with stitches
  • Skin grafts
  • Skin flaps

In rare cases, we may recommend consultation and coordination with another surgical specialty for reconstruction. If necessary, our in-house board-certified oculofacial plastic surgeon, Alison Callahan, is also available to work alongside Dr. Sun for any complex repairs in or around the eye area.

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