Mohs Micrographic Surgery is a special technique used to remove skin cancers. It is a complicated, time consuming technique and is therefore only used in special circumstances. The usual indications for using Mohs Surgery to treat a skin cancer are:
- a skin cancer that has been shown to be an aggressive type on the biopsy
- a skin cancer that has beenincompletely removed or previously treated and recurred
- a skin cancer that is near an important structure where the sparing of as much normal skin as possible is desired such as the nose, ear or eyelid
- a skin cancer in a cosmetically important area such as the face or neck
- a skin cancer that is considered large which would be greater than 9mm on the face or greater than 2 cm on the trunk or extremities
The procedure is done in our office under local anesthesia and can usually be accomplished in one day.
The actual technique involves several steps. First, the involved area is anesthetized with injections using a very small needle. This is the only painful part of the procedure and fortunately only lasts 1-2 minutes. However, you should know that we had a special ingredient to our anesthetic which makes the injection even less painful. The rest of the procedure should involve very little discomfort. Skin cancers tend to be softer than the surrounding skin and often the bulk of the tumor is first removed by scraping off this soft tissue. Then a thin layer of surrounding tissue is removed surgically. The above steps usually take only 10-15 minutes. Next, the layer of skin that has been removed is processed and prepared for examination under the microscope by the Mohs surgeon. This is also done in our office. This tissue is carefully mapped and color-coded with dyes to enable the Mohs surgeon to determine the exact location of any residual cancer. The processed tissue is then carefully and systematically examined under the microscope. If any residual skin cancer is found, then the entire process of tissue removal is repeated, but only for the areas where residual tumor remains. We can usually determine if you are going to need additional tissue removed before your local anesthetic wears off. If you need additional tissue removed we will give you more local anesthetic for the next stage while you are still numb from the previous injections. Therefore if you need additional anesthesia it should not be painful. The processing and microscopic examination usually takes approximately 1 hour, but may take longer if the amount of tissue removed is larger than average. It is impossible to determine ahead of time how many times this process will need to be repeated.
We ask that you come to the office at your appointed time and expect to stay 5-6 hours, but it does not always take that long. Take your medications, if any as usual, including aspirin or any other blood thinners you may be on. We encourage you to bring a book and/or media player with headphones/earbuds with you, since most of your time will be spent waiting. We also insist that you have someone drive you home. If you so desire, someone can also wait with you during the time you are in the office. After the skin cancer has been removed, we will decide what to do about the wound created by the surgery.
Sometimes the wound can be allowed to heal by itself, which may take several weeks. Sometimes the wound can be closed directly with stitches if the wound is not too large, or if the wound is larger thensome of the surrounding skin may be rearranged and moved over to cover the wound (this is called a flap) and then the area closed with stitches. Sometimes skin is removed from another area of the body and grafted onto the wound. We will decide together what will be best for you after all the skin cancer has been removed.
You will be given written instructions after the mohs surgery on how to care for the treated area. All wounds drain somewhat. Those that are allowed to heal without placing stitches drain more. Therefore, frequent bandage changes are necessary -- at least once a day. Mild bleeding can also occur following this type of surgery. If bleeding should happen, apply direct, constant pressure without stopping for 20 minutes. If the area is still bleeding after pressure then call the office, even if it is after regular office hours. You can expect some mild discomfort after the anesthetic wears off. Usually plain Tylenol is sufficient to control the pain. Swelling and bruising are quite common after this type of surgery and should resolve in 2-3 weeks. Skin cancers can often involve the nerves of the skin and it may take as long as a year or two until normal sensation returns. It is possible that the area may stay numb permanently. Also, the skin area that has been treated often feels tight. This tightness improves after several weeks to months. Anytime a skin cancer is treated, no matter what method, a scar always occurs. We will try to give you the best cosmetic result possible; however, the most important aspect is removing the entire tumor with the highest chance of it not recurring. Fortunately, scars tend to improve with time, but the maximum improvement may take as long as 1-2 years.
Rest assured we will always be available to you should you have any questions or develop problems.