wound healing

1. WOUNDS AND WOUND
HEALING
Presented by – Mrs. Khushnasib
Associate Professor

2. INTRODUCTION
• A wound is a damage or disruption to the normal anatomical
structure and function.
• Wounds range from simple break in the epithelial integrity of the skin
and extending to damage of deeper structures – subcutaneous
tissues, tendons, muscles, vessels, nerves, parenchymal organs and
bone
• Wounds may be intentional, accidental or following a disease process
• A wound represents a violation of natural defence barriers and
encourages invasion by micro-organisms.
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3. CLASSIFICATION OF WOUNDS
• Aim of classification: diagnosis and stratification, prognostic
information, guide management, uniformity of documentation
• Wounds can be classified using the following criteria:
• Time - acute, subacute, chronic
• Aetiology – surgical, penetrating trauma, blunt trauma, burns, frost bite
• Morphology – abrasion, incision, laceration, degloving, ulceration
• Degree of contamination – aseptic, contaminated, septic
• Complexity – simple, complex, complicated
• For Surgical wounds: CDC, ASEPSIS, Southampton
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4. CLASSIFICATION OF WOUNDS
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Avulsion/Degloving injury
Contusion
Abrasion
Crush injury
Laceration
Burn injury

5. CLASSIFICATION OF WOUNDS
CDC Classification of Surgical Wounds
• Clean: Elective, not emergency, non-traumatic, primarily closed; no
acute inflammation; no break in technique; respiratory,
gastrointestinal, biliary and genitourinary tracts not entered.
• Clean-contaminated: Urgent or emergency case that is otherwise
clean; elective opening of respiratory, gastrointestinal, biliary or
genitourinary tract with minimal spillage (e.g. appendectomy) not
encountering infected urine or bile; minor technique break.
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6. CLASSIFICATION OF WOUNDS
CDC Classification of Surgical Wounds
• Contaminated: Non-purulent inflammation; gross spillage from
gastrointestinal tract; entry into biliary or genitourinary tract in the
presence of infected bile or urine; major break in technique;
penetrating trauma <4 hours old; chronic open wounds to be grafted
or covered.
• Dirty: Purulent inflammation (e.g. abscess); preoperative perforation
of respiratory, gastrointestinal, biliary or genitourinary tract;
penetrating trauma >4 hours old.
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7. CLASSIFICATION OF WOUNDS
ASEPSIS Classification of Surgical Wounds
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8. CLASSIFICATION OF WOUNDS
Southampton Classification of Surgical Wounds
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9. PHYSIOLOGY OF WOUND HEALING
• Wound healing is a complex process involving coordinated
interactions between diverse immunological and biological systems
• Wound healing is a continuous process but can be differentiated into
four time-dependent phases for understanding:
• Coagulation and haemostasis phase
• Inflammation phase
• Proliferation phase
• Remodelling phase
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10. PHYSIOLOGY OF WOUND HEALING
Coagulation and Haemostasis Phase
• Primary aims:
• Prevent exsanguination
• Provide matrix for invading cells in the later phases of healing
• Rapid reflex vasoconstriction occurs following noxious insult
• Process effective only in transversally interrupted vessels
• Vasoconstriction effective for few minutes until hypoxia and acidosis
set in
• Formation of clot via coagulation cascade further limits blood loss
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11. PHYSIOLOGY OF WOUND HEALING
Inflammatory Phase
• Primary aim: establish an immune barrier against invading micro
organisms
• Further divided into:
• Early inflammatory phase
• Late inflammatory phase
• Involves both the humoral and cellular immune response
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12. PHYSIOLOGY OF WOUND HEALING
Early Inflammatory Phase
• Begins during the late phase of coagulation
• Serves the following functions:
• Activates complement cascade
• Initiates molecular events leading to the infiltration of wound site by
neutrophils
• Neutrophils mobilized to wound site within 24-36 h of injury for
phagocytosis
• Phagocytosis is by proteolytic enzymes and free radical species
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13. PHYSIOLOGY OF WOUND HEALING
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14. PHYSIOLOGY OF WOUND HEALING
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15. PHYSIOLOGY OF WOUND HEALING
Late Inflammatory Phase
• Tissue macrophages mobilized within 48-72 h to continue
phagocytosis
• Macrophages have longer lifespan than neutrophils and work better
at a lower pH
• Macrophages facilitates wound debridement, fibroblast proliferation
and maturation, and angiogenesis
• Lymphocytes are the last cells to enter a wound site at 72 h
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16. PHYSIOLOGY OF WOUND HEALING
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17. PHYSIOLOGY OF WOUND HEALING
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18. PHYSIOLOGY OF WOUND HEALING
Proliferative Phase
• Commences on day 3 of injury and lasts for 3 weeks
• It involves the following processes:
• Fibroblast migration,
• Collagen synthesis,
• Angiogenesis and granulation tissue formation,
• Wound contraction, and
• Re-epithelialization of wound surface
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19. PHYSIOLOGY OF WOUND HEALING
Remodelling Phase
• The phase responsible for the development of new epithelium and
final scar tissue formation
• This phase lasts 1-2 years or more
• Maturation of collagen – type I replacing type III until 4:1 is achieved
• Realignment of collagen fibres along lines of tension
• Decreased vascularity
• Collagen fibres regain about 80% of original strength
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20. PHYSIOLOGY OF WOUND HEALING
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21. PHYSIOLOGY OF WOUND HEALING
Factors affecting wound healing:
• Site of the wound
• Structures involved
• Mechanism of wound
• Contamination
• Loss of tissue
• Other local factors – pressure, vascular insufficiency, radiation
• Systemic factors – malnutrition, diseases, medications, immune
deficiencies, smoking
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22. PHYSIOLOGY OF WOUND HEALING
Factors affecting surgical wound healing:
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Surgical considerations Anaesthetic considerations Patient-related factors
Surgical classification Tissue perfusion Diabetes
Skin preparation Perioperative temperature Smoking
Presence of suture or foreign
body
Concentration of inspired
oxygen
Previous radiotherapy or
chemotherapy
Site, duration and complexity Pain Alcoholism
Suturing quality Blood transfusion Chronic renal failure
Haematoma Jaundice
Mechanical stress on wound Advanced age
Medication
Poor nutrition

23. PHYSIOLOGY OF WOUND HEALING
Classification of Wound Healing
• Primary intention
• Wound edges apposed
• Minimal scar
• Secondary intention
• Wound left open
• Heals by granulation, contraction and epithelialization
• Poor scar
• Tertiary intention
• Also called delayed primary intention
• Wound initially left open
• Edges apposed later when healing conditions are favourable
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24. PATHOLOGY OF WOUND HEALING
• Chronic wound
• Necrotizing soft tissue infections
• Compartment syndrome
• Scars
• Contractures
• Genetic syndromes: Ehlers-Danlos, cutis laxa, homocystinuria,
osteogenesis imperfecta
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25. MANAGEMENT OF WOUNDS
• A correct approach of treating wounds aims to effectively assist the
healing process
• A wound represents a violation of natural defense barriers and
encourages invasion by micro-organisms.
• Chief factors in otherwise immunocompetent individuals are the size
and virulence of the inoculum, the presence of foreign body, and
tissue hypoxia.
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26. MANAGEMENT OF WOUNDS
General principles of acute wound management
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Steps Activities
Assessment Accurate history: magnitude of trauma, contamination
Diagnosis and stratification
Associated injuries: neurovascular, musculoskeletal, visceral
Need for referral/multidisciplinary approach/triage
Preparation Prophylaxis: antibiotic, tetanus
Analgesia/anaesthesia
Exploration, toilet and debridement
Haemostasis
Definitive treatment Closure: when, how, where, which first?
Drainage
Referral/multidisciplinary approach?
After care Dressings
Removal of sutures/splints
Surveillance for complications
Physiotherapy and rehabilitation

27. MANAGEMENT OF WOUNDS
Preparation
• Antibiotics have a role in reducing wound infections, but they do not
replace the need for aseptic technique, atraumatic handling of tissue and
good perioperative wound care.
• The role of antibiotic prophylaxis in clean wounds is controversial. Factors
to consider:
• clinical environment with rate of infection > 4%,
• patient-related risk factors,
• disastrous consequence of infection such as in implant surgeries,
• The choice of antibiotic varies depending on the site of trauma or surgery
• Adjuncts to antibiotic prophylaxis: perioperative normothermia and oxygen
supplementation
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28. MANAGEMENT OF WOUNDS
Preparation
• A decision regarding tetanus prophylaxis must be made in every
patient with an injury; more likely in wounds:
• contaminated with soil or manure
• with extensive devitalized tissue (especially muscle)
• in the lower limbs, axilla
• caused by bites
• that are punctured deeply.
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29. MANAGEMENT OF WOUNDS
Preparation
• Acute post-traumatic wound is often contaminated, hence the need
for wound toileting and debridement before definitive treatment
• Wound cleaning should be done promptly with water, saline and or
antiseptics (chlorhexidine, cetrimide, povidone iodine)
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30. MANAGEMENT OF WOUNDS
Preparation
• Debridement is the removal of foreign matter, necrotic and devitalized
tissue from the wound
• Debridement aims to achieve a clean, well perfused area with low bacterial
count.
• Surgical and mechanical debridement are commonly used in acute wounds
• Autolytic, enzymatic and biological methods are more relevant in wounds
presenting late or in chronic wounds
• The skin must not be undermined because of the blood supply may be
compromised.
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31. MANAGEMENT OF WOUNDS
Wound Closure
• Of two types: Direct and Transplanted closure
• Direct closure:
• For clean wounds with satisfactory vascularity, haemostasis and not under
tension
• Sutures, staples, skin tapes and cyanoacrylate glue are commonly used in
direct closure of wounds.
• When non-absorbable tools are used for closure, removal is often by: 48
hours in the eyelid, 4 days in the face, 7–10 days in the trunk, 10–12 days in
the upper limb, 10–14 days in the lower limb
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32. MANAGEMENT OF WOUNDS
Wound Closure
• Transplanted closure refers to when non-native tissue is used to
achieve closure, such as skin grafts and flaps
• Local or distant flaps are preferred to skin grafting if:
• the wound bed is not very vascular
• bare tendons or nerves are exposed
• the wound is over a bony prominence
• radiotherapy or repeat surgery is contemplated
• better cosmetic effect is required.
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33. MANAGEMENT OF WOUNDS
Wound Drainage
• Wound drainage is usually employed if the risk of a fluid collection is
estimated to be high
• Blood and wound fluid collecting within or under a wound may give
rise to:
• pressure effects (vascular compromise, airway compromise, pressure on
nerves, compartment syndromes)
• infectious complications (infected seroma, infected haematoma, abscess)
• unsightly swellings
• A closed system of drainage is preferred because it is aseptic.
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34. MANAGEMENT OF WOUNDS
Adjuncts to Wound Healing
• Bioengineered skin
• Electrostimulation
• Growth factors
• Hydrotherapy
• Hyperbaric oxygen
• Lasers
• Negative pressure therapy
• Ultrasound
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35. Thank you
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