As human beings, we tend to falter and fall (physically and mentally as well), and when that happens we suffer cuts, bruises burns and other injuries. Every day we use sharp objects like knives, razors, saws etc and accidently cut ourselves. Children injure themselves while playing. The world is full of glass, metals, chemicals, electricity, machines and others - sources of injuries and burns; we have now come to accept them as part of our everyday life. While we can be careful and reduce the incidence of injuries we can never completely eradicate them like polio or small pox.
‘Even a beautiful rose –hides a lowly thorn.’
The point of this entire introduction is that when injuries result we often ask
‘why did this happen to me?’
We need to put aside this question and turn to the important issue- managing the injury and its complication.
First of all how does a normal wound heal?
When the skin is cut or injured the first protective body mechanism is to stop the flow of blood by contraction of the blood vessels and forming blood clots (haemostasis). Once this is done the body decides to repair the damage. It does this by sending certain cells to the area of damage (macrophages, neutrophils, monocytes and lymphocytes). These ‘worker cells’ do the following
- They clear the wound of debris and dirt
- They fight infection
- They send signals to bring in ‘specialists’ who will rebuild the damaged tissue.
Growth factors are chemical substances released by a lot of cells (macrophages, platelets, endothelial cells, fibroblasts, lymphocytes) that encourage and promote various activities needed to heal a wound like –cell multiplication, matrix synthesis, blood vessel growth. A lot of studies are underway to determine if we can externally add some growth factor and influence or encourage or hasten the wound healing and avoid scar formation.
The next step is to start rebuilding the damage and so the wound needs some ‘specialist cells’ called fibroblasts. These cells lay down a strong scaffold with collagen fibers and ground substance or matrix which will provide a basic structure and strength to the healed area. New blood vessels (angiogenesis) form and grow into the healing area to bring in more ‘workers and specialist cells’ to rebuild the damage. During this time some worker cells are repairing the skin surface (called epithelisation). This hyperactivity (proliferative phase) is needed in the initial phase to repair the wound. This phase of repair (3-4 weeks) then slows down and the body starts to focus on remodeling the tissues (remodeling phase) so that they will start to look like normal skin. Remodeling of the tissues can go on up to a year.
During the repair –a lot of collagen (scaffold) and ground substance(cementing substance, extra cellular matrix) is laid down to strengthen the wound and during the remodeling stage the extra collagen is removed or replaced to get the end result to resemble normal skin. These are also some specialist cells called myofibroblast that cause the wound size to decrease by contracting the wound edges. As long as these process are going on normally there may be no scar or a fine mature scar may develop.
When the baby is in the womb (in utero), wounds heals without scarring, but we lose this ability after birth. We are still unable to understand why exactly fetal wounds heal without scars. However when there is an imbalance of the repair phase, and the remodeling phase i.e. when the fibroblast cells in the remodeling phase lay down too much collagen and the body is slow to remove it- the problem starts to manifest in the form of a hypertrophic scar or keloid. Beside the liver which minimally regenerates tissues, we don’t have the capacity to regenerate limbs or organs as we see in lizard which can regenerate the whole tail that is lost.
figure: showing the stages of wound
healing and how scars result.
Why do we need to understand wound healing?
Wound healing is a complex process. As we have discussed, there are four phase or stages of wound healing. Understanding the stages helps us to realize that wounds take time to heal and that we need to be patient. It also helps us to look closely at wound healing and our researchers and doctors can work on various parameters to hasten wound healing. We can evolve and develop better wound care products like different wound dressings for better wound management. Growth factors play a very important role and studies are underway to introduce growth factors into the wound and hasten wound healing. By studying the healing process in different types of wounds and ulcer like diabetic wound, surgical wounds, pressure sores, burn wounds, acute, chronic and non healing wounds, venous ulcers etc we are able to individualize treatment for each case and help the patients have a faster recovery.
We now understand non healing wounds and ulcers in a better way and treat them. Wound care companies are involved in serious research trying to outdo their competitors by providing the best wound care products. Newer techniques in wound management like VAC( vacuum assisted healing),enzymatic wound debridement, hyperbaric oxygen therapy, maggot therapy, growth factor therapy, skin substitutes, advanced wound dressings, keratinocyte culture (skin culture) have all developed from our understand of wound healing. Even plastic surgeons, burn surgeons, general surgeons and others decide how and when to interfere surgically to heal a wound through their understanding of the wound healing processes. In addition we are now able to establish wound assessment and wound care guidelines for proper wound management.
Following a minor injury the skin heals without any visible mark. If this was not the case, our body would be a museum of scars as we suffer minor injuries almost daily that we hardly notice.
So then what exactly is a scar?
The word scar simply means any visible mark left on the skin or mucosa in the process of healing of any injury or wound.
What are the types of scar?
There are four Scenarios:
1. No scar
2. Mature scar
There are four Scenarios:
1. No scar
2. Mature scar
3 atrophic scar
4. hypertrophic scar
5. Keloid scar
5. Keloid scar
What are mature scar?
Mature scar are scars that develop in the course of wound healing. These scars are not physically troublesome- they do not cause pain, itching, are not thickened or red in colour and do not tend to grow in size. The main problem with this scar are they are they are a cosmetic problem especially when they are on the exposed parts like face, arms, or legs.
Mature scar are scars that develop in the course of wound healing. These scars are not physically troublesome- they do not cause pain, itching, are not thickened or red in colour and do not tend to grow in size. The main problem with this scar are they are they are a cosmetic problem especially when they are on the exposed parts like face, arms, or legs.
Related sites:
Wound Healing Society - What's Happening Now
http://www.woundheal.org/
Canadian Association of Wound Care
http://www.cawc.net/
WUWHS - World Union of Wound Healing Societies
http://www.wuwhs.org/
http://www.woundheal.org/
Canadian Association of Wound Care
http://www.cawc.net/
WUWHS - World Union of Wound Healing Societies
http://www.wuwhs.org/
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