Wide excision of skin lesions and skin graftingMedical editor Truls Ryder MD
Oslo University Hospital
For wide excisions, additional tissue around the scar where a tumor has previously been removed, is excised. Wide surgical margins around the removed tumor may reduce the risk of relapse. In cases where a lot of skin has to be removed and it is difficult to close the wound primarily, it may be necessary to use a skin graft or flap reconstruction to cover the defect.
If the area to be covered is large, the risk for relapse is considered to be high or the patient's condition does not allow an operation with comprehensive flap reconstruction, and the condition of the patient permits it, the defect will usually be covered with a skin graft.
For a skin graft, the skin tissue is moved from one part of the body to another without preserving the tissue's blood supply. New blood vessels grow from the recipient area in a few days after the operation.
Skin grafts may be full-thickness or split-thickness:
- A full-thickness skin graft is used for small defects where the cosmetic and functional requirements are higher. This especially applies after excision of skin changes and skin tumors in the head/neck region. Full-thickness grafts consist of both the dermis and the epidermis.
- Split-thickness graft is often used for larger defects, and in cases where cosmetic considerations are not possible or needed. Split-thickness grafts consist of the epidermis and parts of the dermis.
Wide excision is carried out for:
- Tumors in the skin where a wider margin is needed to reduce the risk of relapse
- Cases in which all tumor tissue was not removed during the first operation
- Cure the disease
- Reduce the risk for recurrence
- Plastic surgery instruments
For skin grafts, the following are also used:
- The procedure is carried out under local or general anesthesia.
- The area to be removed is outlined on the skin followed by administration of local anesthesia with adrenalin along the edge of the lesion, to reduce bleeding. An interval of 10 minutes should be allowed before the incision is started.
- An incision is made along the outline.
- The area is dissected until an adequate margin of depth is reached.
- The tissue is lifted at one end with forceps and using a scalpel, the appropriate skin thickness is separated from the underlying tissue.
Hemostasis is maintained with diathermy. It is necessary to maintain sufficient hemostasis to prevent postoperative bleeding and formation of an underlying hematoma. Too much diathermy can lead to loss of tissue viability, which will compromise healing of the wound.
- The specimen is usually marked with a thread, at one end or at an area of interest, to facilitate the pathology evaluation of the specimen.
For small defects, the area behind the ear is often used as donor site. For larger defects, it is common to use skin from the groin, inside of the upper arm, or other places where the donor defect can be closed directly with sutures.
- The graft is dissected by separating the dermis from underlying fat tissue. It is important that the skin is free of fat before it is positioned onto the defect.
- The donor site is closed with sutures.
- The edge of the transplant is adapted as precisely as possible to the edges of the defect. The full-thickness graft heals by growth of blood vessels from the dermis into the edges of the defect.
- The graft is attached with "interrupted sutures" where 6 cm remain on each end of the sutures.
- A loop suture is placed around the edge of the graft.
- A compression bandage (buttoning) is placed on the graft and tied securely using ends from the interrupted sutures.
It is easiest to obtain donor skin from flat skin surfaces. A common donor site is the thigh.
- The skin is rubbed with oil.
- The skin is stretched. A compressed air dermatome or manual skin knife is used to harvest the skin. The instrument functions like a cheese slicer cutting the skin in very thin layers.
- The transplant is moistened and placed on a glass surface.
- It is then put through a mesher (aperture puncher). Depending on the size of the mesh surface, the harvested transplant will increase in size, to cover a larger wound surface.
- The transplant is positioned onto the defect and stapled/sutured in place.
- Excess donor skin is resected.
Dressing of split-thickness graft:
- The transplanted area may be covered my Mepitel or Jelonet.
- On top of this is put a compression bandage/sterile sponge or similar to maintain immobility of the graft.
- Alternatively a VAC pump may be applied (Vacuum Assisted Closure Device). Mepitel is similarly put onto the transplanted area and thereafter a sponge covered by a transparent plastic drape. This is connected to a vacuum pump. The vacuum extracts fluid and stimulates proliferation of blood vessels.
- If possible the operated area should be elevated to reduce postoperative edema and bleeding.
- The sutures are removed after 7-14 days.
- For a full-thickness graft, the compression bandage should remain untouched for about 1 week.
- For split-thickness transplants, the compression bandage is to remain untouched for one week if the recipient site is considered clean. If there is danger of infection, the compression bandage should be changed and the graft should be inspected after 2-3 days.
- VAC bandages are changed/removed after 3-5 days depending on the conditions.
- The skin graft should be protected from trauma and force for 2-3 weeks.
- Exercises and training which may lead to damage of the graft should be avoided for 3-4 weeks.
- Protect the graft and donor site from sun exposure.