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What is Mohs Surgery?

Mohs surgery, also known as Mohs micrographic surgery, is a surgical procedure to treat skin cancer. During the surgery, individual layers of skin tissue are excised (removed) and inspected under a microscope one at a time until all cancerous tissue has been removed. The main objective of Mohs surgery is to excise as much of the cancerous skin tissue as possible while ensuring minimal harm to surrounding healthy tissue.

Following skin cancer removal, wounds are reconstructed to preserve function and aesthetic appearance. Some wounds may be allowed to heal on their own, while others will require stitches, skin grafting (skin from another location removed and used to cover the defect), or a flap to close the wound.

Indications for Mohs Surgery

Mohs surgery is a procedure to treat simple skin cancers like squamous cell carcinoma and basal cell carcinoma, as well as more complex skin cancers, such as melanoma, which may be found on the eyelids, ears, nose, neck, lips, hands, and feet. It is indicated for the removal of skin lesions where it is important to preserve surrounding healthy tissue for functional and cosmetic purposes, and for skin cancers that:

  • Are unlikely to be removed through regular surgery
  • Have not responded to earlier treatments
  • Have recurred
  • Are large in size
  • Contain scar tissue
  • Have borders that are not clearly defined

Preparation for Mohs Surgery

In general, pre-procedure preparation for Mohs surgery involves the following steps:

  • A review of your medical history and a physical examination to check for any medical issues that need to be addressed prior to surgery.
  • Depending on your medical history, social history, and age, you may need to undergo tests such as blood work to help detect any abnormalities that could compromise the safety of the procedure.
  • You will be asked if you have allergies to medications, anesthesia, or latex.
  • You should inform your doctor of any medications or supplements you are taking or any medical conditions you have such as diabetes.
  • You may be asked to refrain from certain medications such as blood thinners or aspirin for a week or two prior to the procedure.
  • Refrain from smoking for at least a week before surgery and several weeks after, as it can hinder the healing process.
  • Refrain from alcohol at least 24 hours before and after surgery, as well as herbal and vitamin supplements for at least a week before surgery, to reduce the risk of increased bleeding and blood pressure.
  • You may be asked to shower with an antibacterial soap prior to surgery to reduce the risk of infection.
  • Signed informed consent will be obtained from you after the pros and cons of the procedure have been explained.

Procedure for Mohs Surgery

Mohs surgery is usually performed on an outpatient basis utilizing a local anesthetic, so you will be awake throughout the procedure. Your surgeon removes the visible raised area of the tumor with a curette (a scoop-like instrument). A thin layer of healthy tissue immediately surrounding or underlying the excised tumor is removed and used as a guide to the exact location of the tumor. The tissue is processed, stained, and examined under a microscope by your surgeon. If any indication of cancer cells is found in the sample, your surgeon will remove and examine another tissue sample taken from the specific region indicated on the map. These steps are repeated until no cancer cells are detected under the microscope. This helps your surgeon remove all traces of cancer cells without undue removal of healthy tissue. Finally, depending on the extent of the tissue excision performed, your surgeon may use sutures, skin flaps, or skin grafts to close the wound or leave the wound open to allow it to naturally heal on its own.

Post-Mohs Reconstructive Surgery

Many techniques can be employed as part of post-Mohs reconstructive surgery to preserve the aesthetic appearance and function of the treated area. Techniques chosen by your surgeon will depend on the type, size, and location of your skin cancer. The techniques can include the following:

  • Skin Grafts: Skin grafting is a technique that involves removing a patch of skin from one area of the body (the donor site) and transplanting it to another area to cover the wound.
  • Flap Technique: This is a surgical technique that involves transferring a piece of healthy skin tissue that has a good vascular supply from one region of your body to another. The flap technique is most utilized for any necessary facial reconstruction.
  • Bone Grafting: Bone grafting is a surgical technique in which a damaged area of the bone (with bone loss or missing bone) is replaced with a bone graft (healthy bone tissue) usually taken from the skull and shaped to be placed into the excision site.
  • Tissue Expanders: Tissue expansion is a procedure to promote the growth of healthy supplementary skin for the replacement of damaged skin. It involves the placement of a balloon-like expander under the skin near the damaged area, which is then filled with a saline solution over time to prompt the skin around it to stretch and grow.
  • Cartilage Grafting: Cartilage grafting is a surgical procedure to replace damaged cartilage with healthy cartilage. The most common donor site for cartilage is the ear, but rib cartilage is also utilized.

Postoperative Care and Recovery

In general, postoperative care instructions and recovery after Mohs surgery will involve the following steps:

  • You will be transferred to the recovery area where your nurse will closely observe you for any allergic or anesthetic reactions and monitor your vital signs.
  • Mohs procedure is normally a same-day surgery unless your doctor instructs otherwise.
  • You may experience pain, inflammation, and discomfort in the operated area. Medications are prescribed as needed to manage these.
  • Application of ice packs to the operated area for a couple of days every 2 to 3 hours when awake is also recommended to reduce swelling and bruising.
  • Antibiotics are also prescribed to address the risk of surgery-related infection.
  • Instructions on incision site care and bathing will be provided to keep the wound clean and dry.
  • Refrain from strenuous activities and lifting heavy weights until the first follow-up visit. A gradual increase in activities is recommended.
  • A follow-up appointment will be scheduled to monitor your progress.

Benefits of Mohs Surgery

Some of the benefits of Mohs surgery include:

  • Minimal muscle trauma
  • Minimal scarring
  • High success rate in cancer tissue removal (99%)
  • Preserves healthy skin tissue
  • Use of local anesthesia
  • On-site lab work results
  • Same-day surgery
  • Cost-effective
  • Improved cosmetic outcome

Risks and Complications of Mohs Surgery

Mohs surgery is a relatively safe surgery; however, as with any surgery, the following risks and complications may occur:

  • Infection
  • Bleeding
  • Discoloration
  • Scarring
  • Nerve damage
  • Cancer recurrence
  • Pain
  • The need for additional reconstructive surgery