Detailed presentation on wounds, classification, phases of healing and management for resident doctors, medical students and nurses

1. WOUND HEALING
BY
DR GEORGE OWUSU

2. OUTLINE
• Introduction
• Historical perspective
• Definition of terms
• Aetiology of wounds
• Classification of wounds
• Types of wound healing
• Phases of wound healing
• Factors affecting wound healing
• Complications of wound healing
• Conclusion

3. INTRODUCTION
• The occurrence of wounds and various bodily
injuries has been with man since time
immemorial.
• However, with the benevolence of nature and in
the words of Joseph Hunter “the injury alone has
in all cases a tendency to produce disposition and
means of a cure”
• Nonetheless, aberrations in the norm, could lead
to abnormal healing patterns such as keloid and
hypertrophic scar formation or intense chronicity
even to a point of Malignant changes.

4. HISTORICAL PERSPECTIVE
• Summarians at about 2000BC noted to employ
two forms of treatment.
• In 1650Bc Edwin Smiths Papyrus noted to have
described at least 48 different types of wounds.
• However, Egyptians were first to differentiate
between infected and non infected wounds.
• In 1550BC, Ebers Papyrus related the use of
concoctions containing honey, lint and grease for
wound treatment.
• Galen Pergamum (120-201 AD) noted that moist
wound environment was required for adequate
healing.

5. HISTORICAL PERSPECTIVE
• The next major stride was the discovery of
antiseptics in the 19th century and their
importance in reducing wound infections.
Noted by Gnaz Philips and Joseph Lister
• The 20th century and the development of
Polymeric dressings.
• Currently, the practice of wound healing
encompasses manipulation and use among
others; inflammatory cytokines, growth
factors and bioengineered tissues.

6. DEFINITION OF TERMS
• WOUND: This is a breach in the anatomical
integrity of skin and other tissues associated
with disruption of the structure and
functionality of the tissue.
• WOUND HEALING: This is the effort of injured
tissue to restore their structural integrity and
normal function after an injury. It is not a
single event but a continuum of processes
beginning at the moment of injury continuing
through months to years.

7. AETIOLOGY OF WOUNDS
• Road traffic accidents/ motor vehicle collision
• Sporting injuries
• Falls
• Physical violence (assaults, fights, wars)
• Chemical injuries
• Burns
• Radiations
• Surgeries

8. CLASSIFICATION OF WOUNDS
• Closed and open
wounds
– Closed wounds (skin
remains intact)
• Bruise
• contusion
– Open wounds (Breach or
loss of skin)
• Abrasion/ friction burns
• Puncture wounds (bites)
• Penetrating wounds

9. CLASSIFICATION OF WOUNDS
• Open wounds (Breach or
loss of skin)
• Perforating wounds
• Incisions
• Lacerations
• Avulsions
• Crush injuries

10. CLASSIFICATION OF WOUNDS
• ACS Classification of surgical wounds
– Clean wounds
– Clean contaminated wounds
– Contaminated wounds
– Dirty wounds
• Simple and complex
• Tidy and untidy

11. TYPES OF WOUND HEALING
• Primary wound healing/ healing by first intention:
– Wound edges well apposed
– Normal healing occurs with minimal scar
• Secondary wound healing/ Healing by secondary
intension:
– Wound is left open (extensive tissue loss)
– Heals by granulation and contraction
– Presence of increased inflammation and proliferation
– Formation of poor scar

12. TYPES OF WOUND HEALING
• Tertiary wound healing/ delayed primary wound
healing:
– Wound initially left open (infection or for further
debridement)
– Edges apposed later when healing condition is favorable
– Heals well with less scar with tensile strength
approaching that of primarily healed wound.
• Epithelialization:
– form of healing in wounds of partial thickness involving
only the epithelium and superficial dermis
– Abrasions, friction burns, superficial partial thickness
burns

13. PHASES OF WOUND HEALING
• Normal wound healing follows a pattern of
various characteristic cellular population and
biochemical activities which can be divided into
overlapping phases including:
1. inflammatory phase
– Haemostasis
– Inflammation
2. proliferative/ Regenerative phase
3. maturation/ Remodeling phase

14. PHASES OF WOUND HEALING
• INFLAMMATORY PHASE:
• Haemostasis:
– Immediate
vasoconstriction of injured
vessels and reflex
constriction of adjacent
small arteries and
arterioles occur in the first
5-10 minutes of injury.
– Following events platelets
adhere to the exposed sub
endothelial matrix protein/
collagen via specific
adhesive glycoprotein.

15. PHASES OF WOUND HEALING
– The aggregating platelets
are activated releasing
contents of their
vesicular granules,
causing further
aggregation of platelets.
– This leads to formation
of the Primary
Haemostatic plug

16. PHASES OF WOUND HEALING
– However definitive
homeostasis is
achieved when fibrin
formed by
coagulation cascade
is added to the
platelet mass with
clot retraction/
compaction

17. PHASES OF WOUND HEALING
• INFLAMMATION:
– Vasoconstriction and
haemostasis is followed by
vasodilatation .
– This heralds the
characteristic signs of
inflammation
– Followed by diapedesis of
inflammatory cells into the
extravascular space and
migrating to the wound.

18. PHASES OF WOUND HEALING
• INFLAMMATORY PHASE:
• Neutrophils are the earliest predominating
cells in the wound.
• Peak presence at about 24-48hrs post injury
• Their primary role is phagocytosis of bacteria
and tissue debris.
• Migration is by release of chemokines
including bacterial products, c3a, c5a , TGF-β,
TNF-α, IL-1

19. PHASES OF WOUND HEALING
• INFLAMMATORY PHASE:
• The second population of inflammatory cells invading the .wound
are macrophages derived from circulatory monocytes.
• Achieve significant number from about 48-96 hours post injury
• Like the Neutrophils, it participates in wound debridement by
phagocytosis and antimicrobial activities with release of reactive
O2 species
• Plays a pivotal role in activation and recruitment of other cell via
secretion of cytokines, growth factors as well as cell-cell
interaction.
• Also plays significant role in the regulating angiogenesis, matrix
deposition and remodeling.

20. PHASES OF WOUND HEALING
• INFLAMMATORY PHASE:
• T-lymphocytes invade the wound later and peak at about
one week post injury.
• Plays a role in the modulation of the wound environment
and regulation of fibroblast collagen synthesis.
• The bridge the transition from the inflammatory phase to
the proliferative phase of wound healing.
• N/B the aim of the inflammatory phase is to clear the
wound surface for proper foundation laying of wound
healing substances.

21. PHASES OF WOUND HEALING

22. PHASES OF WOUND HEALING
• PROLIFERATIVE PHASE:
• This is the phase of granulation tissue
formation and consist of different overlapping
sub-phases/ stages including:
– Fibroplasia
– Matrix deposition
– Angiogenesis
– Epithelialisation

23. PHASES OF WOUND HEALING
• FIBROPLASIA:
• Fibroblast from cells surrounding the wound migrate into the wound at
about days 5-7.
• The proliferate and lay down collagen fibers of sub-types I and III
• Type III collagen predominates early in the wound and later replaced by
type I
• At first, he collagen fibrils are fine and few but as healing proceeds the fiber
cell ratio increases.
• During this phase, the tensile strength of the wound rapidly increases from
one to six weeks and slowly up to a year.
• Fibroplasia is mediated by growth factors including: fibroblast growth factor,
PDGF

24. PHASES OF WOUND HEALING
• MATRIX DEPOSITION:
• Fibroblast synthesize and secrete extracellular matrix
substances including
– Fibronectin
– Fibrilin
– Glycoaminoglycans (GAGs) and proteoglycans.
• GAGs- hyaluronic acid, chondroitin, dermatan chondroitin
sulphate, heparan sulphate, keratan sulphate.
• The matrix forms the major ground substance of
granulation tissue.
• supports the epidermal and endothelial cell migration and
proliferation and as a scaffold for collagen fiber deposition.

25. PHASES OF WOUND HEALING
• ANGIOGENESIS:
• This involves sprouting of new vessels from
existing ones, starts about 2-3 days after
injury and involves:
• Vasodilatation in response to nitric oxide and
increased permeability to VEGF.
• Separation of periendothelial cells (pericytes)
and breakdown of basement membrane to
allow formation of a vessel sprout.
• Migration of the endothelial cells towards
the area of tissue injury with cellular
proliferation behind lead point.
• Suppression of endothelial proliferation and
migration by contact
• Remodeling of capillary tubes, deposition of
basement membrane and pericytes.

26. PHASES OF WOUND HEALING
• EPITHELIALIZATION:
• Within 24hrs, epidermal cells at the
edges of the become transformed
into a homogenous syncytial mass.
• The layer migrates to the centre of
the wound, passing below the
existing scab or escar and stops when
in contact with the opposite side.
• This phase is stimulated by the
epidermal growth factors released
by platelets and keratinocytes.

27. PHASES OF WOUND HEALING
• MATURATION/ REMODELING
• Scar Remodeling
– Collagen remodeling begins approximately 3 weeks
after injury
– Characterized by reorganization of previously
synthesized collagen, with degradation by matrix-
metalloproteinases
– The rate of synthesis and degradation reach
equilibrium and the wound becomes less cellular as
apoptosis occurs.
– Extracellular matrix, including collagen, is continually
remodeled and synthesized in a more organized
fashion along stress lines.

28. PHASES OF WOUND HEALING
– The number of cross-links between collagen fibers
increases
– Realigned, highly cross-linked collagen is much
stronger than the collagen produced during the
earlier phases of healing.
– After the initial 6 weeks, tensile strength increases
though it never reaches the tensile strength of
unwounded tissue

29. PHASES OF WOUND HEALING
• MATURATION/ REMODELING
• Wound Contraction
– Myofibroblasts are specialized fibroblasts that
contribute to wound contraction
– The wound edges are pulled together by the
contractile forces supplied by the Myofibroblast.
– Begins in the 4- 5th day period after wounding and
continues for 12 to 15 days or until the wound
edges meet.
– Excessive contraction can lead to contracture, a
pathologic scarring that impairs the function and
appearance of the scar.

31. FACTORS AFFECTING WOUND
HEALING
• LOCAL FACTORS:
• Site of wound
• Mechanism of wounding
• Loss of tissue (large defect)
• Foreign body
• Wound infection
• Presence of necrotic tissue
• Poor apposition
• Vascular insufficiency (Arterial or Venous)
• Previous radiation
• Recurrent Trauma
• Underlying disease (osteomyelitis, malignancy)

32. FACTORS AFFECTING WOUND
HEALING
• SYSTEMIC FACTORS:
• Age
• Malnutrition
• Vitamins and minerals
• Obesity
• Diabetes mellitus
• Anaemia
• Jaundice
• Use of steroids
• Use of cytotoxic medications
• Cigarette smoking

33. COMPLICATIONS OF WOUND HEALING
• Wound dehiscence
• Wound infection
• Haemorrhage
• Fistula formation
• Hypertrophic scar
• Keloids
• Incisional hernias
• Contractures
• Malignant transformation

34. CONCLUSION
• As wounds continue to abound, the
knowledge, concept and art of achieving
proper wound healing continues to grow.
• However, for the achievement of a proper
healing, efforts must be put in place to assist
the presumably self sufficient natural healing
parameters, by ensuring an adequate and
optimal healing environment devoid of
negative limiting factors for a proper outcome.

35. THANK YOU!!!!

36. REFERENCES
• Schwartz principles of surgery; F.C. Bruncicardi
et al, 10th edition, 2010
• Principles and practice of Surgery including
pathology in the tropics; E. A. Badoe et al, 3rd
edition, 2000
• Robbins and Cotran pathologic basis of
disease; Vinay kumar et al 9th edition, 2015
• https//emedicine.medscape.com/woundheali
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