General data about burn

>> BURN WOUNDS SURGERY

 

If you have sustained deep partial/deep burns which cover an area larger than your palm surface, you may require an operation. The surgery consists of burn wound removal followed by the application of a temporary or permanent covering.
Surgery can be performed either in the first 3 days or after 2 weeks from the time of injury. The decision will be influenced by several factors that need to be taken into consideration:
A) You have to be well enough to have surgery. Heart or lung problems, kidney disease, diabetes may get worse after burn
Injury and further treatment will be required to make you feel better.
B) The risks of anaesthesia and surgery complications need to be assessed. Children under the age of 12 months and elderly people have a higher risk of complications.
C) The operation needs to be planned carefully in order to minimise the possibility of complications due surgery or anaesthesia. Most burn operations take 3 hours, but some may be longer.
d) Infection.
e) Bleeding.

 

WHY DO WE SOMETIMES OPERATE ON BURNS IN THE FIRST FEW DAYS?

Deep burns that cannot heal by themselves are operated on quickly to reduce the risk of infection and to get the patient out if hospital as early as possible

 

WHY DO WE SOMETIMES OPERATE ON BURNS AFTER A COUPLE OF WEEKS?

Burns that heal by themselves in a week or two do not need an operation. They may have scars that are better or no worse than after surgery.
In patchy burns, some areas may heal and then safely can be operated on after 2 weeks.
Some patients need a period of preparation for surgery. (e.g. patients with other medical problems)

 

HOW CAN WE GET RID OF BURNED SKIN?

Wound debridement consists of removal of damaged tissue and preparation of the wounds for treatment.
Debridement exposes the true depth and severity of burn injuries and can be done using one of the following methods:
A) your body will itself get rid of the dead tissue over a period of time.
B) removal of the dead tissue with a waterjet
C) removal of the dead tissue using surgery (surgical knife),
D) some enzymes get rid of the dead tissue.
Debridement may be painful and adequate pain relief or anaesthesia may be required.

 

WHAT DOES BURN SURGERY INVOLVE?

Burn surgery involves two phases:
A) first stage is removal of dead tissue with a surgical knife / waterjet;
B) second stage consists of covering the defect made by removal of dead tissue.

The dead tissue is removed until healthy living tissue is seen. Usually this tissue is within or just below the skin. Sometimes the burn is so deep that other tissues are damaged.
Depending on the extent of burn wound excision, you may require a blood transfusion afterwards.
The defect left after excision is covered either with grafts of your skin or with skin substitutes. The best coverage is given by your own skin.

 

HOW CAN YOUR SKIN COVER THE AREAS LEFT AFTER REMOVAL OF BURN WOUNDS?

The most frequent method is to take a skin graft with a special instrument (dermatome). A skin grafting is shaving a thin layer from an uninjured skin. The area where the skin was taken from is called the donor area.

                                                                                                                                         ^ top of page

WHAT IS A SKIN GRAFT?


The skin has two layers (see skin structure).

A skin graft contains the surface layer and some of the underlying skin layer (dermis).If the dermis layer is taken partially, the skin is split thickness. A skin graft that has all the dermis is a full thickness skin graft. A split thickness skin graft can be thin or thick, depending on the thickness of the harvested dermis. When a thin split thickness skin graft is harvested, the donor area will heal in 2 weeks but the graft may be very thin. The thicker a graft is taken, the more likely it is to leave a mark at the donor site.
If you take a full thickness skin graft, the donor area has to be closed with stitches because it does not heal on its own.

 

WHAT IS A SPLIT THICKNESS SKIN GRAFT?

A skin graft that contains the superficial and part of the second skin layer (epidermis and part of the dermis) is known as split-thickness skin graft. This type of graft can be raised with special instruments (dermatome) with a width up to 4 inches and as long as 10-15 inches from flat body surfaces (thigh, back).
After the skin graft has been taken, in order to increase its surface, holes may be made in the graft with a machine. Skin grafts can be made to go further by “meshing” them with multiple small cuts made by a machine. This does tend to leave a long term pattern in the skin. With this method, the surface area can be doubled or trebled.

The graft is fixed to the defect with staples, tissue glue or stitches. In order to survive, the skin graft has to “take” on the underlying tissue.
A skin graft “takes” when it picks up circulation of blood from the healthy tissue beneath it. This needs the graft to be held in place securely, without movement for several days. After 5 to 7 days, the graft is firmly attached and the dressings are removed.

The place from where the skin graft was taken (donor area) is similar to a graze or superficial burn and it may take up to 2 weeks to heal. After complete healing, the same donor area may be used again for further skin graft harvesting if necessary.

 

WHAT IS A SPLIT THICKNESS SKIN GRAFT ?

 

Another method is to cut a small piece of skin and to grow the cells from the superficial layer of the skin in special conditions in the laboratory (culture cells). In about 2 weeks, cells grown in special environment can be placed over areas with skin defect.
The cultured skin cells will constitute the centres from where cells migrate on the surface of the defect and form a new skin.
The newly formed skin will be less robust than a skin graft, but cultured cells are used frequently in patients with large burns (more than 50%).
A combination of skin graft and cultured cells give good results in severe burns.

                                                                                                                                          ^ top of page

Skin structure

 

Split skin graft

Skin graft 5 days after application

Healed skin graft

WHAT ARE THE SKIN SUBSTITUTES?


When skin graft availability is not enough to cover the defect after removal of dead tissue, burn surgeons may use skin substitutes which are temporary or permanent wound coverings. They will prevent the wound from getting infected and also will help the healing process. When permanent coverage is available, the temporary skin substitutes are removed.

 

WHICH ARE TEMPORARY SKIN SUBSTITUTES?

Temporary coverings will be used in areas where the adherence of skin graft is uncertain or can be used as a protection over a very thin and largely expanded skin graft to allow maximum coverage.
The three categories of temporary dressings are:
A) Allograft (skin grafts from human tissue donors).
B) Xenograft (treated animal products).
C) Synthetic skin coverings.

 

ALLOGRAFT

Allograft is a skin graft harvested from another patient (relative) or donor. Allografts were used frequently in 1950s to the 1990s, but nowadays due to limited supply of donor skin and the risk of transmissible disease, the usage is less. Any allografts used nowadays will be obtained from a tissue bank where very strict processes are followed to minimise the risk of transmissible diseases. The primary indication for its use is to cover a large area left after excision of burn wound. It can stay up to 4 weeks but your body will ultimately reject it. By that time, permanent skin substitutes or products from your own skin are ready to cover the defect. Allografts are also used to cover a widely expanded skin graft, sealing the spaces between the skin graft bridges during the healing process.

 

XENOGRAFT

Xenograft is skin graft harvested from species other than humans and has been used for hundreds of years in burn wound coverage. Nowadays, pig skin is the most commonly used xenograft.
It is processed in the laboratory before use. It provides temporary cover and excellent pain control for donor sites and superficial burn wounds, which are clean.

                                                                                                                                          ^ top of page

 

 

 

 

 

 

 

 

 

 

 


SYNTHETIC SKIN COVERING

 

A lot of research has been put into developing synthetic skin coverings.
These coverings usually combine synthetic membranes to imitate skin and protect burn wounds from the environment, with biological substances that stimulate and promote skin healing.

 

Biobrane is an example of a temporary synthetic skin substitutes.
It is made from:
- A silicone thin layer that has small holes in it. Through these tiny pinprick holes, wound secretions find their way out. This layer protects the burn from the environment.
- Underneath the silicone layer there is a nylon mesh upon which is bonded proteins extracted from pigs. These substances bond strongly with the surface of superficial burns. After about 2 weeks, the skin is healed and the Biobrane may be peeled off. Biobrane is used frequently in children who have sustained scald injuries providing good wound cover and excellent pain relief.

 

Transcyte is another temporary skin substitute. It has a bi-layer structure similar to that of Biobrane:
– The outer layer is a silicone thin layer that mimics the skin properties and has tiny pinprick holes.
– The inner layer is a knitted nylon scaffold which is layered with human skin cells group in culture in the laboratory. These cells will produce substances that facilitate the healing of burn wounds.

After 2 weeks, the skin underneath heals and Transcyte is peeled off. Transcyte is used frequently in children that have sustained scald injuries and provides excellent pain relief. Transcyte needs to be stored in the freezer prior to use.



                                                                                                                                          ^ top of page

BIOBRANE structure

BIOBRANE glove applied on a foot

Transcyte structure

WHICH ARE THE PERMANENT SKIN SUBSTITUTES?

The aim of permanent skin substitutes is to replace the whole thickness of the skin and to improve the quality of the healed skin after severe burns. These products are used either early to help with healing, or later for scar release.
Their structure is much more complex than that structure of the temporary skin substitutes. The products that have been developed are designed after two models.
- The first model is a one layer structure and aims to replace either the superficial (epidermis) or middle (dermis) layer of the skin but not both.
- The second model uses the two layer structure. The outer layer is either synthetic or has skin cells. The inner layer forms new skin tissue and take active part in wound healing. Cells and substances that promote healing can be attached to the scaffold.

 

Epicel is used especially in patients with very large burns and provides only the surface layer of the skin. If you sustain extensive burns, a small piece of your skin (1 inch x 1 inch) is taken. The skin cells from superficial layer are extracted and made to grow and multiply. In this way you can obtain a thin layer of skin cells that is 10,000 times larger than the piece that we took from you (1 inch square). It may take up to 2 - 3 weeks till the products are ready.
Often burn is removed at an earlier stage and temporary skin substitutes are applied until the culture cells are ready. When Epicel is ready, the wounds are cleaned and the product is applied immediately.

 

Alloderm is a product that contains human donor skin from which the surface layer has been removed. After harvesting, the human skin is treated to avoid infection and rejection. The main indication is when the replacement of soft tissue defects is needed.
This product is used mainly in the recovery period when scars need to be released. Alloderm does not bring a superficial layer and requires application of a thin skin graft.

 

Integra is a bi-layer product. The inner layer is a scaffold made from proteins and fibres. In this scaffolding, the patients own cells migrate and grow.
The outer layer is a transparent silicone sheet that acts as a barrier protection.

The main indications for Integra are the treatment of large burns as well as in the reconstructive procedures after burns.

After removal of burned tissue, Integra is applied and secured over the defect. It will take around 2-3 weeks till blood vessels form and patients own cells start to grow into the scaffold. It is essential that Integra does not move on the underlying tissue because the newly formed blood vessels can be damaged and the product will be lost. After three weeks the outer silicone layer is removed and a thin skin graft is applied.

                                                                                                                                         ^ top of page

 

 

 

 

 

 

 


Epicel          Alloderm

Integra application

   
| Search | Terms & Policy | Contact | Links | Newsletter |
© 2006 Burn Centre Care.All rights reserved