What is skin grafting? [ Hot oil burns, second ( 2nd) degree deep and third ( 3rd ) degree burns, a discussion on skin grafting]

Dear doctor,

My husband suffered burns to his arm from hot oil and he was admitted in the hospital for treatment.

He was given first aid, painkillers ,antibiotics, and the wound was dressed with a white cream(silver sulphadiazine), Now it is three weeks after the burn and though most of the areas have healed, a small patch still remains about 5cm x 6cm, which looks red and refuses to heal. The attending surgeon feels that a skin transplant is needed.

He seems very busy and has not given us a good idea about this procedure. Doc, could you please tell us more.. Is it safe?? What happens if we don’t do it?

Thanks for your time,

Lucy.

Dear Lucy

Thank you very much for the letter. Am sorry to hear your husband suffered a burn.

Hot oil burns are a serious affair, since oil when heated can reach temperatures of more than 200 degree Celsius compared to boiling water. The burns are therefore often deep, sometimes 3rd degree. It will also depend on the time of contact and temperature of the oil itself.

In your husband’s case, it appears that only a small part has been a third degree burns, as the rest of the areas have already healed in two- three weeks. The red area of this unhealed burn wound appears to be area which has no skin. The body tissue cells and blood vessels grow within it forming ‘granulation tissue’. 

Wounds heal by two ways-

A) The remnants of skin element within the wound itself grow and form new skin

B) If no skin elements are present within the wound, the skin cells at the edge of wound multiply and slowly corner the wound.

Small tiny wound can heal like this but big wounds may never heal or heal very slowly. Leaving a large non healing wound open for a long time can lead to infection spreading to the whole body. Besides even when they heal they form a lot of scar tissue which can be troublesome. Scars can be painful, itchy and even restrict movement, especially when they from across a joint leading to ‘contractures’. The picture below shows a young unfortunate lady who suffered deep 2nd degree and third degree burns and ended up in scars and contractures.

Hence wounds which are unlikely to heal by themselves must be supported by bringing in new skin – a procedure called ‘skin grafting’. The grafted skin must also be of adequate size replacing the lost skin or otherwise again hypertrophic scars,  keloid scars and contractures may result.

What is skin grafting?

Skin grafting is a surgical procedure where the skin is taken from one part of the body and applied over another area where there is no skin.

The part from which it is taken is called the ‘donor site’ and the part or wound over which the skin is applied is called the ‘recipient site’

Doc, if you take the skin from the donor site won't it leave a wound?

Well, the skin has two layers- the dermis and the epidermis and there are two ways to take a skin graft:

a)    Full thickness skin graft

b)    Split thickness graft

By full thickness we mean both the epidermis and the dermis layers- This means that the donor area will have no skin and therefore either it must be closed, sutured or stitched primarily, otherwise  you may have to apply another split skin graft over it. Sometimes when large areas of full thickness skin is needed then the donor area may be expanded by a tissue expander where a silicone balloon is inserted under the skin and slowly expanded by filling saline water.

When the adequate size is reached the balloon is removed and the extra stretched skin is used as a skin graft. By this technique we get extra skin from the donor site.

By split thickness or partial thickness we mean a graft which has epidermis and small part of dermis. Here the donor area can heal on its own as part of the dermis is still left behind (usually two weeks)

Doc, what sites can be used on a skin graft?

Technically any site can be used as a skin graft.

In burn patients with major burns sometimes we even take skin from the scalp, foot and hands as there is shortage of unburnt skin.

Usually the preferred donor sites are the unexposed areas of the body like the thighs and buttock since they are covered by normal clothing. But one can take skin from the legs, abdomen, chest and back areas. The burn surgeon must discuss all these options with the patient before planning a skin graft procedure as different patients will have different ideas and needs.

Doc, how is the skin graft taken?

Skin grafts are taken depending on what types of grafts are needed and how big an area is to be covered. In major burns large skin pieces are needed and therefore split skin grafts are preferred, Here the donor area usually heals in 2 weeks. These split skin grafts are taken either manually using a blade - called the humby knife, or by an electric dermatome   that is motorized and helps to take skin grafts. For small skin grafts the silver blade or knife is good and can be used. Experienced surgeons can manage to take small grafts even with the regular humby knife. The picture below show the humby knife and the Aesculap  (division of the B. Braun Melsungen AG) ( http://www.bbraun.com/ ) electric dermatome that is often used to harvest skin grafts.

Doc, my three year old son has a bad burn on his hand from an electrical socket shock. The surgeon feels he has to do a skin graft procedure. Can I donate skin from my body to my son, he seems so fragile and I don’t want the doctor to create another injury on his body. Will this work permanently?
nigella
Goa

No, this is a temporary procedure as we are not doing a skin transplant but a skin graft.

In organ transplant procedures like the kidney transplant or liver transplants, the tissues are matched so that no rejection occurs and immunosuppressants (medications used to reduce our immune reaction so that the foreign donor organ is not rejected) are freely used to prevent rejections.

However in skin grafting a donor matching is not done and medications are not given therefore once this skin from the mother is applied, it stays on and provides some temporary cover. Sometimes the burn wound underneath may heal if the burn is not very deep. Otherwise one will have to get a skin graft procedure done again, this time the skin from the same individual has to be used if we must have a permanent graft.
Skin grafts from live humans are taken only in exceptional cases as we have other alternatives.

Animal skins from the pig (porcine skin grafts) are also used in the same way. Similarly (Cadaver skin) skin from cadavers (Human dead bodies) is also used as temporary covers. These skins are often taken and stored in skin banks by aseptic techniques.

The cadaver from which the skin is harvested must be free from HIV, hepatitis and other communicable diseases otherwise the recipient stands the risk of getting these diseases.
 Skin substitutes like 'Integra' is another option.

Doc, what about the donor site, how long does it take to heal?

Well, the donor site from where the graft is taken usually heals in about 2 weeks. If the donor site is not soaked with discharge then the dressings need not be changed. However if one suspects infection or finds excessive soakage of the dressing then it should be changed. Some pain is expected but routine painkiller medications are adequate. Once healed, the donor site may take time to get back its original skin color. Also one has to use moisturizers as the new skin will need some support till it regains all its functions and direct sunlight over the site must be avoided to prevent hyper pigmentation.

The video below shows a hand of a patient who suffered 2nd degree deep burns and third degree burns and needed a skin grafting procedure. The video shows how full function of the hand can be achieved after skin grafting which is very important for the patient though this may not be possible all the time and will depend on the burn damage.

(an original article from @asktheburnsurgeon+)