Skin grafting refers to the transfer of skin from one part of the body to the other to cover raw areas in the body. Through this procedure, the defect in the skin is reconstructed irrespective of the reason for the defect
The skin is the largest organ of the body and comprises two layers. However, a skin graft is a segment of skin comprising of epidermis and variable part of the dermis which is elevated and separated from its blood supply.
- Epidermis: It is a protective outer layer of the body. Epidermis protects the body from infection, trauma and dehydration.
- Dermis – It is a tissue located below the epidermis that contains living cells such as sweat glands, hair follicles, nerve endings, and blood vessels.
Types of skin grafts –
The thickness of the dermis determines the type of skin graft, viz.
Split-thickness skin graft:
A split-thickness skin graft (STSG) consists of the entire epidermis and a varying portion of dermis. These grafts do not contain hair follicles, sebaceous glands, and sweat glands. The outcome of a split-thickness skin graft is usually dry and hairless.
A split-thickness skin graft is further divided based on its dermal thickness:
- Thin - 0.008- to 0.012-mm
- Medium - 0.012- to 0.018-mm
- Thick - 0.018- to 0.030-mm
Full-thickness skin graft –
A full-thickness skin graft includes the epidermis and entire dermis. It is similar to normal skin, especially in terms of color match, texture and scope for hair growth.
Indications of skin graft
Skin grafting is the most common form of Reconstructive Surgery performed for decades. Grafts are required to cover a wound that cannot be closed with sutures and leaving it alone would take a long time to heal or may likely cause the development of scar contractures.
Also, skin grafting is done to cover wounds that do not have exposed bare bone, bare cartilage, or open joints; neither is it the first choice to cover wounds in cosmetically important areas like the face and functionally important areas like hands.
The most common injuries suitable for skin graft are –
- Post-traumatic defects/ raw areas
- Post infective raw areas
- Primary Burns or residual post burn raw area
- Diabetic foot ulcers
- Vitiligo to add pigment in the white patches
- In any other procedure where there is likely to be skin shortage like syndactyly release.
Split-thickness skin graft
A split-thickness skin graft is preferred when the cosmetic appearance of the wound is unimportant. Also, the wound is relatively large and or infective, wherein the use of a full-thickness skin graft is not recommended.
Use of Split-thickness skin graft
- To cover acute and chronic cutaneous ulcers cover post-traumatic raw areas
- To cover sites that require observation for tumour recurrence
- To cover white patches in depigmenting disorders
- To line orbital cavities following orbital exenteration surgeries
- To cover post burn raw areas to speed the healing process and reduce the loss of fluid
Use of Full-thickness skin graft
- To cover and restore skin in cosmetically important areas like the face where color and texture match is essential like infra-orbital area, temple area
- To cover raw areas post-surgical release of joined fingers and following contracture releases like eyelid contracture, finger contracture, etc.
- To surgically correct the depigmentation conditions through punch grafting
- To facilitate punch grafting( hair transplantation) and mini grafting
Contraindications of skin graft
Contraindications of skin graft depend upon location, nature of the wound and type of skin graft.
Contraindications to the use of Split Thickness Skin Graft are
- A good cosmesis is required at the affected area
- Ensure functionality of the area
Contraindications to the use of Full-Thickness Skin Graft are
- Poor vascular supply
- High risk of graft necrosis
- Infected and/or large wound
Procedure for a split-thickness skin graft
Skin grafting surgery is done under local/ regional/general anaesthesia depending on the location f defect and size.., Donor site for a split-thickness graft is usually the inner or outer thigh or buttock. For large aw areas, the entire thigh skin is harvested to cover the raw area. Raw area is prepared by scooping to remove and unhealthy tissue or infective material, washed and all bleeding is controlled.
The graft is then spread on the raw area and anchored with staples or sutures. Meanwhile, a sterile dressing covers the dressing site for 3 to 5 days and plaster is given to aid in immobilizing the grafted area.
Procedure for a full-thickness skin graft
Donor site is usually the back of the ear for graft on the face and neck; for grafts below the neck, full-thickness graft is taken from the groin crease or other concealed areas.
A gauze template is taken of the defect and placed onto the donor site. An appropriate size donor graft is marked and removed from the donor site.
Donor site is prepared. Graft is placed and anchored with sutures. The surgeon takes care to place the graft in apposition to the wound bed avoiding any shearing forces and minimizing any chances of graft failureGraft dressing is done after 7-8 days. Donor site is closed with sutures.
- Few days of hospital stay recommended for proper healing of the graft as well as the donor site
- Issues in graft or recovery on account of infection, collection of blood or fluid under the graft, smoking, and improper blood supply to the graft area.
- General Instructions for proper healing of the graft
- Keep the bandage dry and clean at all times.
Graft loss is the most important complication that can occur, however, if the wound is prepared well for grafting then loss is unusual.
Post graft care:
Dressings are usually out by the 15-18 days post grafting. The patient is then asked to apply a moisturizer to the graft twice a day for about 2-3months to make it feel and look like natural skin.