Mohs Micrographic Surgery
Mohs surgery is a highly technical, microsurgical technique invented by surgeon Frederic Mohs. It is the most advanced and single, most effective procedure for removing Basal Cell Carcinoma (BCC) and Squamous Cell Carcinoma (SCC) – the two most common forms of skin cancer.
Mohs surgery allows the Mohs surgeon to check that all cancer cells have been removed at the time of surgery. This increases the likelihood of a cure and reduces the need for additional treatments. Because Mohs surgery provides extremely precise removal of cancerous tissue, healthy tissue is spared and because of its high cure rate, it is now recommended as the treatment of choice for high-risk non melanoma skin cancers in specific areas such as the eyelids, nose, lips, ears and scalp as well as other areas of the face and body.
Your dermatologist is trained to determine when this technique should be used and will refer you to a specialist Mohs Surgeon. The Skin Hospital has been performing Mohs surgery since 1991. We operate the largest Mohs centre in the southern hemisphere, training more Mohs surgeons than anywhere else in Australia. Recognised as a Mohs centre of excellence we now have 17 Mohs surgeons conducting more than 2,500 procedures annually. They are supported by outstanding Mohs nurses and technicians dedicated to delivering the best patient outcomes.
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Mohs Surgery Questions
What is the cure rate?
Using the Mohs surgery technique, the cure rate is greater than 95%, even if other forms of treatment have failed; however, no one can guarantee a cure rate of 100%.
Who performs Mohs surgery?
Many dermatologists throughout Australia have been trained in skin cancer surgery. When patients require more extensive surgery, however, they are referred to a qualified Mohs surgeon. The period of training to be a qualified Mohs surgeon is a one-year fellowship, during which the dermatologist acquires extensive experience with all aspects of the technique.
Mohs surgery at The Skin Hospital involves a team of people. Your Mohs surgeon is the head of that team but will be supported by a group of highly skilled and specially trained doctors, nurses and technicians.
The Skin Hospital has been performing Mohs surgery since 1991. We operate the largest Mohs centre in the southern hemisphere, training more Mohs surgeons than anywhere else in Australia. Recognised as a Mohs centre of excellence we now have 17 Mohs surgeons conducting more than 2,500 procedures annually. They are supported by outstanding Mohs nurses and Mohs technicians dedicated to delivering the best patient outcomes.
The Mohs team cares about you and wants to help in relieving any anxiety or fear you may have by making your surgery day as comfortable and relaxed as possible.
How is the surgery performed?
The suspicious skin lesion is treated with a local anaesthetic so there is no feeling of pain in the area. A thin piece of tissue is removed and carefully divided into pieces that will fit on a microscope slide.
The edges are then marked with specially coloured dyes, a map of the tissue which has been removed is made and the tissue is frozen by a pathology technician. Thin slices can then be made from the frozen tissue and examined under the microscope by the dermatologist.
A pressure dressing is applied to the surgical site and the patient is asked to wait in a recovery area while the tissue is being processed.
The doctor will examine the slides under the microscope and be able to tell if any tumour is present. If cancer cells remain, the patient is taken back to the procedure room where another layer of tissue is removed. The procedure is repeated as often as necessary until no cancer cells remain. This process preserves as much healthy skin as possible. After the first layer is taken, a long-acting anaesthetic is used to keep the area numb for many hours.
How long will the surgery take?
The removal of each layer of tissue takes approximately 1–2 hours. Only 20-30 minutes of that time is spent in the actual surgical procedure; the remaining time is needed for slide preparation and for the doctor to read the slides. On average, the surgery usually requires removal of 2–3 layers of tissue (called stages). The whole process including sewing up the wound, usually takes 4-6 hours. Some difficult or larger cases may take longer.
What happens after the tumour has been removed?
After Mohs surgery you will be left with a surgical wound. This wound may be repaired in one of the following ways:
- closing the wound, or part of the wound, with stitches
- various skin closures, such as grafts and flaps, or reconstructive procedures
- healing by spontaneous granulation
- referral for reconstruction to a plastic or oculoplastic surgeon
Wound Closure & Post Op Care
A wound may be stitched up in a straight line (side-to-side closure) or by making extra incisions to move adjacent loose skin into the wound site (flap closure) or with a skin graft. Side-to-side closures are more common for smaller wounds. This involves some adjustment of the wound and stitching the edges together. The procedure speeds healing and offers a good cosmetic result: for example, the scar can be hidden in a wrinkle line. The scar is always larger than the size of the skin cancer.
With a flap closure, skin is moved from an area next to the surgical site. This leads to more stitches than you may have anticipated and a scar with a geometric shaped closure such as a T, Z, or W etc. The final cosmetic result is usually very pleasing as again the surgeon places the wounds so as to hide them in natural creases or folds as much as possible.
With grafts, a second wound is created to obtain skin (this is the donor site). This is usually taken from a ‘non-cosmetic’ site (from behind the ear, for example) to minimise scarring. The stitches will remain in place for approximately 5-14 days, depending on the site of the lesion. Specific wound care instructions will be given to you on the day of surgery.
Your wound may be left to heal by spontaneous granulation which involves letting the wound heal itself. Experience has taught us that there are certain areas of the body where nature will heal a wound as nicely as any further surgical procedure. If the resultant scar is unacceptable, some form of cosmetic surgery can be performed at a later date. If the wound is allowed to granulate it usually heals in four to eight weeks and requires daily dressing changes.
Your post-operative care will be thoroughly explained to you by a nurse and you will also be given written instructions.
It is usual to expect some discomfort after your surgery. We request that you not take Aspirin, Ibuprofen or Disprin but use Paracetamol for pain relief. Your doctor may prescribe you something stronger if necessary.
Bleeding occurs occasionally following surgery. If this should happen, the bleeding can be controlled by the use of pressure. Leave the dressing in place and apply pressure with a gauze or similar pad. You may support yourself against a couple of pillows in a semi-upright position and apply constant pressure over the bleeding site for 20 minutes.
Swelling is common around the surgical site. It can be minimised by applying ice packs (or frozen peas) on the area for 10 minutes every hour for at up to 24 hours after surgery.
You will be given instructions on how to care for your wound at the end of your surgery and arrangements will also be made for your sutures to be removed. Some patients will be asked to return to The Skin Hospital the day after surgery to have their wound checked.
Do not make arrangements for sporting activities or travel after your surgery as you will need to rest for at least one week to prevent post-operative complications. We also advise that you do not undertake strenuous exercise for at least one week or more after your sutures have been removed.
Risks and Complications
Our number one priority is total removal of the skin cancer. Incompletely removed skin cancers can recur and in some cases spread to other parts of the body.
All surgery carries risks and can develop complications. After your Mohs surgery, these may include; bruising, swelling, bleeding, infections, numbness, scarring, and skin tightening or stretching. Most of these problems will resolve with time but you will always be left with a scar.
Swelling and bruising are very common, especially when surgery is performed around the eyes and nose. These conditions subside by keeping your head elevated and by using ice-packs regularly for the first 24 hours following surgery. If redness and pain don’t subside within two days, or if the wound begins to drain or discharge, you may have an infection and you should contact your doctor.
Nerve damage is usually temporary and recovers, however can be permanent in some cases if the cancer is extensive and the nerve is involved. Scarring from the surgery usually settles well. Flaps and grafts take time to heal but improve significantly within 3-6 months. They may require massage, cortisone injections or further surgery to improve the scar. Sometimes the extent of skin cancer and the complexity of the wound may require a larger reconstruction, which can leave a more obvious scar. Your doctor can discuss with you a range of options to deal with this circumstance.