1. By: M. Rustom Plastic Surgeon
WOUND HEALING
By: M. Rustom
Plastic Surgeon

2. Definitions
A wound by true definition is a breakdown in the protective function of the skin; the loss of continuity of epithelium , with or without loss of underlying connective tissue (i.e. muscle, bone, nerves) following injury to the skin or underlying tissues/ organs caused by surgery, a blow, a cut, chemicals, heat/ cold, friction/ shear force, pressure or as a result of disease, such as leg ulcers or carcinomas.

3. Healing is the interaction of a complex cascade of cellular events that generates resurfacing, reconstitution, and restoration of the tensile strength of injured skin.

4. Phases of Wound Healing
1- Phase of hemostasis
2- Phase of Inflammation
3- Phase of proliferation
4- Phase of maturation ( remodeling )

5. Phase of Hemostasis The 1st phase after the occurrence of the wound.
Aims to stop the bleeding by forming a clot.
3 physiological processes take place:
- Vasospasm.
- Platelets aggregation.
- Activation of the coagulation cascades
This phase last about 24 hours.
The end products of this phases prepares for the phase of inflammation.

7. Phase of inflammation 2nd phase to take place.
Aims at defending the wounded area against invading microorganisms & prepares for the wound proliferation.
Characterized by activation of the immune cells & inflammatory mediators.
The following events take place:
- Vasodilatation
- Increased vascular permeability
- Activation of Neutrophils & Macrophages ( 1st 48 hours )
- Activation of T-lymphocytes ( after 72 hours )
- Release of inflammatory cytokines

9. Phase of Proliferation
Initiated by the end products of the inflammatory phase.
Aims at:
- Filling the wound gap with granulation tissues
- Contracts the wound edges
- Epithelialize the wound surface
Main elements include :
- Fibroblast which is main elements in granulation tissue formation.
- Myofibroblasts
- Epidermal cells

11. Phase of Maturation The final process of wound healing.
Aims at restoring the scar tissue formed to the best possible resemblance to the original damaged tissue.
The main events are:
- Gradual reduction of the amount of tissue enzymes.
- Water resorption of the scar.
- More cross linkage of the collagen
- Transformation of collagen III to collagen I

14. Healing types Healing by primary intension
Healing by secondary intension
Students inputs ????

15. Abnormal wound healing
Factors affecting wound healing:
Local factors :
- Excessive damage
- Infection
- Foreign body
- Excessive tension

16. Regional Factors :
- Poor tissue perfusion
- Venous congestion
- Lymphatic obstruction
- Peripheral neuropathy
- Climetric
- Local radiation

17. Systemic Factors:
- Poor nutritional status
- Uncontrolled DM
- Smoking
- Immunocompromised conditions
- Drugs, eg chemotherapy, steroid & cytotoxic therapy
- Uncontrolled morbidities, esp endocrine diseases & heart failure

18. Questions to the students
How does DM affect wound healing ?
How does smoking affect wound healing ?
What are the differences between keloid & scar hypertrophy ?

20. Wound infection
Wound contamination - the presence of bacteria within a wound without any host reaction
Wound colonisation - the presence of bacteria within the wound which do multiply or initiate a host reaction
Critical colonisation - multiplication of bacteria causing a delay in wound healing, usually associated with an exacerbation of pain not previously reported but still with no overt host reaction
Wound infection - the deposition and multiplication of bacteria in tissue with an associated host reaction

21. Clinical features of wound infection
Pain
Excessive discharge
The presence of biofilm of slough
Delay in wound healing
Surrounding oedema & erythema
Systemic features : fever, leukocytosis & eventually systemic sepsis

23. Treatment Local treatment: - Removal of foreign bodies if any
- Debridement & desloughing
- Prompt dressing
- Antibiotics ( culture based ) if indicated
- Control of the medical comorbidities

25. THANK YOU