phases of wound healing,delaying factor,types of wound closure,various types of wounds

1. Wound healing
By Ammara fayyaz

2. wound
• Definition:It is a circumscribed injury which is caused by external
force and it can involve any tissue and organ.
• A wound is a break in the integrity of the skin or tissues often which
may be associated with disruption of the structure and function.
or
• A cut or break in the continuity of any tissue, caused by injury or
operation.

3. • Regeneration:
Replacement of dead or damaged cells by functioning cells of same
structure and function.
• Exp bone,liver.
• Repair:
Replacement of dead or damaged cells by granulation tissue which
matures to form scar,Function is lost .
• Exp skin.

4. Phases 0f wound healing

5. •Inflammatory phase (day1-4)
• Limit blood loss Debridement Sealing the wound
• Inflammatory phase 1). Hemostasis 2). Inflammation
• Hemostasis:Vessel damage ---- bleeding---- platelet plug ---- thromboxane
A2 --- Vascular contraction and coagulation pathway activation --- fibrin
frame work deposition ----Hemostasis (Activated by intrinsic & extrinsic
pathways)
• Inflammation: Serotonin/Histamine --- increased vascular permeability
TGF– neutrophil chemotaxis, starts 6-8 hrs, max in 24 hrs Monocyte/
Macrophage– max 3-4 days Phagocytosis, cytokines (IL-1, TNF), mediators
(TGF, PDGF, FGF) Activated by platelet secretary products (PDGF, TGF, FGF,
Serotonin, Histamine)

6. •Proliferative Phase (day 4-21):
• Filling wound gap with granulation tissue
• EVENTS :Fibroplasia, angiogenesis, contraction, re-epithelization
• FIBROPLASIA :Chemotactic TGF, PDGF, EGF, IL-1 Fibroblasts ,peaks at
7th day, Collagen & Matrix deposition, Wound contraction 10-21 days
• ANGIOGENESIS: Hypoxia, lactic acidosis, and FGF-1 (most potent),
heparin, TGF, prostaglandin, Endothelial cells proliferation
• EPITHELIALIZATION: Basal layers thickens, elongates and cells
detaches and migrates

7. •Remodeling phase (day 21-2years):
• Shrinkage ,Loss of oedema, Strength, Scar contraction.
• EVENTS: Regression of vessels & granulation tissue ,Wound
contraction, Collagen remodelling (replacing collagen III with I)
Maximum strength at the 12 week.
• WOUND CONTRACTION: Begin in the proliferative phase (4-5 th day)
Continues throughout the healing process Maximum 10-21 day
.Brings edges close at a rate of 0.6-0.75mm/day Depends on the laxity
of the skin

13. Excessive healing
• Hypertrophic :
• Defined as excessive scar tissue that does not extend beyond the
boundary of the original incision or wound.
• Prolonged inflammatory phase.
• Keloid:
• Defined as excessive scar tissue that extends beyond the boundaries
of the original incision or wound.
• Aetiology is unknown.
• Both hypertrophic and keloid scars shows excess collagen with
hypervascularity, but this is more marked in keloids where there is
more type B collagen.

14. Wound closure types
• Primary(First-intention):
• the wounds are sealed immediately with simple suturing, skin graft
placement, or flap closure.
• Closure at end of a surgical procedure.
• Secondary(Spontaneous-intention):
• no active intent to seal the wound.
• Closes by re-epithelialization, contraction of the wound.
• Larger clot or scab rich in fibrin.
• More inflammation,more amount of granulation tissue,involves wound
contraction.
• Highly contaminated wound.
• Tertiary intension :Initially treated by repeated debridement, systemic or
topical antibiotics, or negative pressure wound therapy for several days to
control infection.
• Surgical intervention, such as suturing, skin graft placement, or flap design is
performed.

18. Rank and wakefield classification of wound