Skin Graft Flashcards
What is a skin graft?
A sheet of skin comprising of epidermis and various degree of dermis which has been completely detached from its original site (donor site) and from its blood supply and transplanted to a new site (recipient site) for skin cover and it is expected that the initial survival will depend on diffusion of nutrients and oxygen from the bed to the graft.
What are Types of grafts: Based on source of graft?
- Autografts (auto transplantation): self
- Hetero graft (aka allograft): same specie
- Xenografts (eg. Pig skin): different specie
What are Types of grafts: Based on amount of damage involved?
- Cultured epidermal graft: only the epidermis is harvested, processed with proteolytic enzymes to detatch it from the dermis after which it is grown in a culture broth.
It is used in conjunction with artifical dermis eg integra - Split thickness skin graft (thiersch graft)
The epidermis and part of the dermis is harvested
Thin, intermediate or thick depending on the dept of the dermis taken. - Full thickness graft (wolfe): Contains the epidrmis and the whole of the dermis
What is meant by The ‘take’ of a graft?
It is a term used to describe the survival of the grafted skin , and it is given in percentage e.g 50%, 75%
The thinner the graft the easier it is for it to take, but has worse cosmetic appearance after healing, it also under goes more secondary contraction
The thicker the graft the poorer the take but the better the cosmetic appearance, it under goes less secondary contraction
What are types of contraction?
Primary contraction: Is the shrinkage size noticed immidiately the graft is harvest
Secondary contraction is the reduction in the size of the graft during wound healing
What is the Indication and conditions for skin graft?
- Wounds with a well vascular bed, including:
Granulation tissue,
Muscles,
Periostium,
Paratenon,
Paraneuron - Leg ulcers
- Full thickness or deep dermal burn
- Post tumor excision
What are the contraindications for a skin graft?
- SEPTIC WOUND WITH SIGNS OF INFECTION
ABSOLUTE CONTRAINDICATION
* WOUNDS WITH THE LANSFIELD GROUP A BETA HEMOLYTIC STREPTOCOCCOUS
RELATIVE CONTRAINDICATION- STAPHYLOCCOUS , PSEUDOMONAS
BARE BONE
BARE TENDONS AVASCULAR FASCIA BED
BARE NERVE WITHOUT NERVE SHEET
ANY AVASCULAR BED
What are the types of skin grafts: Based on meshing?
- Meshed
- Sheet
What is the process of graft take?
- Fibrin glue – Fixes the skin graft to the bed of the recipient site.
- Plasmatic imbibition – Diffusion of nutrients across layers to supply nutrients to the graft.
- Inosculation and neovascularization – Invasion of capillaries to link those on the graft and the formation of new blood vessels.
- Adherence – The deposition of collagen in the fibrin, helping the graft adhere.
Migration of nerve fibers and lymphatics into the graft.
What are the Instruments required for a skin graft?
The instrument used for harvesting a split skin graft is called a skin dermatome
- Hand held or manual : eg humby knife
-Motorised ; electric or air dermatome
The instrument for mesching a skin graft
Skin graft mescher
Hand mesching
Common areas to take split skin graft
- thigh
- the arm
- the buttocks
- scalp
1) post auricular skin
2) pre auricular skin
3) cubital fossa
4) pubic region
Areas available for full thickness graft
Flexural surface with redundant skin:
•Pre- and post-auricular area
•Upper eyelid
•Supraclavicular area
•The groin
•The size is limited because it has to be closed.
What are the Factors that will prevent graft take?
Wrong placement of graft
Tenting of graft over the recipient site
Foreign body
Hematoma
Pus
Infection
Movement of the graft on the bed
Wound infection
Donor site management
THE DONOR WOUND HEALING
EPIDERMAL CELL MIGRATION FROM THE HAIR FOLLICLES AND SWEAT GLAND LEFT ON THE SITE IN SPLIT SKIN GRAFT
WHEREAS IN FULL THICKNESS HARVEST SITE HAVE TO BE CLOSED DIRECTLY
TRADITIONAL METHOD – LAYERED DRESSING
NON ADHERENT LAYER- E.
G SUFRATULLE
ABSORBENT AREA-E.G GAMGEE
HOLDING LAYER- CREPE BANDAGE
WITH THIS METHOD DONOR SITES TAKE 2-4 WEEKS TO HEAL
MODERN DRESSING
OPSITE –TRANSPARENT FILM DRESSING, TAKES 9 DAYS TO HEAL
SILVER ALGINATE I ABSORBENT DRESSING TAKES 10-14 DAYS TO EPITHELISE
BIOBRAME-9DAYS
Recipient site management
OBTAIN A WOUND CULTURE AND TREAT WITH ANTIBIOTICS
PREPARE THE SITE : REMOVE EXCESS GRANULATION TISSUE
ENSURES HEMOSTASIS IS ACHIEVED
LAY THE GRAFT
GRAFT SHOULD BE FENESTRATED OR MESHED,
THIS IS THE PROCESSING OF PEFORATING THE GRAFT IN SET PATTERN , THIS ALLOWS THE EGRESS OF SEROMA AND HEMATOMA FROM UNDER THE GRAFT
IN ADDITION THE PROCESS OF MESHING EXPANDS THE GRAFT BECAUSE IT CREATS LATTICES WITHIN THE GRAFT THEREFORE ALLOWING A LARGER SURFACE TO BE COVERED
