▶ Previous Artlcle : #12-2. Burn Care Using Human Cadaveric Skin
Dressing materials harvested from human tissues have proven efficacy and are easily integrated into the wound site. However, limited availability, complicated grafting procedure and high cost present great challenges to this method. Therefore, animal-derived xenograft materials such as bovine amniotic membrane, porcine skin with structure similar to human skin, and collagen materials derived from bovine and porcine origins have been developed.
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Bioengineered substitutes including Transcyte® (Advanced Tissue Sciences), Dermagraft® (Advanced Tissue Sciences), and Apligraf® (Organogenesis). etc. have widened the choices of a graft material. New products such as Biobrane® that combines silicone coated nylon mesh (developed 30 years ago) with collagen and SUPRATHEL®, a type of polyglycolic acid, have entered the market.
Figure 1. Advantages of amniotic membrane
Figure 2. Anatomy of amniotic membrane
Amniotic membrane
The human amniotic membrane has been widely used in wound and burn care with excellent clinical outcome since its first application to wound treatment in 1910 and to burn care in 1913. Recently, it is used to accelerate epithelization in burn care or following laser resurfacing or dermabrasion. It is also used in treatment of lower limb varicose veins, ulcer, Steven-Johnson syndrome, and Parkinson syndrome, etc. Especially in the field of ophthalmology, it is applied to various treatments of damaged cornea.
The major disadvantage of amniotic membrane is difficult storage and limited availability which makes wider application of it difficult. Therefore, the specimens are cryopreserved, glycerol preserved or lyophilized and irradiated for storage. The amniotic membrane causes little immune response in fresh state and contains various growth factors. With such benefits it has excellent biologic compatibility and promotes the wound healing process. It also prevents evaporative loss of moisture and infection as well as reduces pain.
However, it fails to bring effect in severe second to third degree burns where thick crusts form and cannot be used in infected sites. As the human amniotic membrane has inconsistent availability and complicated storage, cryopreservable products derived from bovine amniotic membrane have been introduced with improved availability (Figure 3).
Figure 3. Dressing materials derived from bovine amniotic membrane
Case 1: Second degree scalding burn on right thigh. Amnisite-BA was applied when exudate subsided three days after wound was sustained. Complete healing was observed 10 days after sustaining wound.
Case 2: Second degree scalding burn on left thigh. Amnisite-BA was applied when exudate subsided six days after wound was sustained. Complete healing was observed 10 days after sustaining wound.
-To be continued-
▶ Next Artlcle : #13-2. Non-allograft Biological Dressing Materials
