WOUND HEALING

1. WOUND HEALING Dr Ryan Fernandes Asst. Professor Dept of General Surgery

2. CLASSIFICATION OF WOUNDS

3. Classification of Wounds 1) Clean Wound: Operative incisional wounds that follow non penetrating (blunt) trauma 2) Clean Contaminated Wound: uninfected wounds in which no inflammation is encountered but the respiratory, gastrointestinal, genital, and/or urinary tract have been entered.

4. 3) Contaminated Wound: • open, traumatic wounds or surgical wounds involving a major break in sterile technique that show evidence of inflammation. • 4) Infected Wound: • old, traumatic wounds containing dead tissue and wounds with evidence of a clinical infection (e.g., purulent drainage)

5. Based on nature of wound • Open wounds • Closed wounds

6. OPEN WOUNDS • Incisions. • Abrasions • Avulsions • Puncture wounds. • Gunshot wounds

7. CLOSED WOUNDS • Contusions. • Haematoma. • Crushing injuries.

8. Based on reparative process Acute wounds : Normally proceed through an orderly and timely reparative process that results in sustained restoration of anatomic and functional integrity. Chronic wounds : Failed to proceed through an orderly and timely process to produce anatomical or functional integrity or proceeded through repair process without establishing a sustained anatomical and functional result.

9. Based on SEVERITY • Minor wounds • Major wounds

10. Minor wounds • It is superficial. • It is away from natural orifices. • There is only minor bleeding. Major wounds • All other wounds.

11. RANK & WAKEFIELD CLASSIFICATION TIDY WOUNDS • Surgical incisons & wounds caused by sharp objects • Incised,clean, healthy wound without any tissue loss • Heals by primary intention

12. UNTIDY WOUNDS They are due to – • Crushing • Tearing • Avulsion • Devitalised injury • Vascular injury • Burns • Fracture of underlying bone may be present • Secondary suturing, skin graft or flap may be needed

13. Wound excision • Adequate anaesthesia provided • Blood less field created • Excision should start from superficial to deeper structures systematically • Blood vessels, nerves, tendons are exposed but left in continuity • Bone fragments with no soft tissue attachments, non vital soft tissues discarded

14. Features of Devitalisedtissues • Devitalised dermis pink • Devitalised muscle dark and lost its sheen and turgor and no twitching SLOUGH –Dead necrotic tissue attached to living tissue

15. Types of wound healing • Healing by first intention (Primary Intention) • Healing by second intention(Secondary Intention) • Healing by third intention (Tertiary Intention)

16. Healing by Primary Intention • Occurs in clean incised wound or surgical wound • Wound edges are approximated with sutures • There is more epithelial regeneration than fibrosis • Wound heals rapidly with complete closure • Scar will be linear, smooth & supple

17. By 24hrs • Neutrophils at the margin of incision. • Increased mitotic activity of basal cells of epidermis Migration of epithelial cells along edges • Fusion of epithelial cells Separation of SCAB.

18. By day 3 • Appearance of : 1). MACROPHAGES 2). GRANULATION TISSUE Collagen fibrils vertically oriented. • Epithelial proliferation continues.

19. By day 5 • Marked granulation tissue • Maximal angiogenesis and neovascularisation • Collagen fibrils begins to bridge the incision • Normal epidermal thickness appears

20. By 2nd week • Continued accumulation of collagen with fibroblast proliferation. • Leukocyte infiltrate • Edema • Vascularity • Increased accumulation of collagen

21. At end of 1 month Scar comprising of cellular connective tissue devoid of inflammatory infiltrate and covered by epidermis is formed.

23. Healing by Secondary Intention Occurs in more extensive loss of tissue 3 important features : a)Abundant granulation tissue b)Increased inflammatory reaction c)Wound contraction

24. Heals slowly with fibrosis • Leads to a wide scar often hypertrophied & contracted • Re-epithelialisation occurs from wound margins

26. Healing by Third Intention - Occurs when the wound is sutured 4-6 days after injury. • Wound is much more contaminated. - Higher degree of scarring.

28. EXTRACELLULAR MATRIX • Collagen • Adhesive glycoproteins • Basement membrane • Elastic fibres • Proteoglycans

29. MECHANISM OF HEALING

30. Mechanisms 1)Epithelialisation 2)Contraction 3)Connective tissue matrix deposition

31. Epithelialisation The process whereby keratinocytes migrate and divide to resurface partial thickness loss of skin or mucosa Examples : Partial thickness skingraft donor sites,abrasions,blisters, 1st and 2nd degree burns.

32. Contraction The mechanism whereby there is spontaneous closure of full thickness wounds

33. Contraction of wound - Starts after 2-3 days. - 80% of original wound size. Factors proposed are: 1) Dehydration. 2) Collagen contraction. 3)Role of Myofibroblasts.

34. Connective tissue matrix formation The process whereby fibroblasts are recruited to the site of injury and produce a new connective tissue matrix.

35. PHASES OF HEALING

36. 1.Inflammatory Phase (Lag or substrate or Exudative Phase) 2. Proliferative Phase (Collagen/Fibroblastic Phase) 3. Remodelling (Maturation Phase)

37. INFLAMMATORY PHASE • Begins immediately after wound healing. • Lasts 4 – 6 days • Features of inflammation present. • Macrophages promote angiogenesis • Polymorphonuclear leukocytes secrete inflammatory mediators & bactericidal oxygen free radicals. • These remove – • Clots • Foreign bodies & • bacteria

38. Proliferative Phase • Collagen & glycosamines are produced by fibroblasts. • Begins in 7 days & lasts for 6 weeks. • 80-90% of the strength is achieved in 30 days.

39. The angiogenesis & fibroplasia causes formation of granulation tissue which contains fibroblasts, neocapillaries, collagen, fibronectin & hyaluronic acid.

40. Remodelling Phase • Begins at 6 weeks & lasts 2 years • Inflammation diminishes. • Angiogenesis ceases. • Fibroplasia stops. • There is maturation of collagen by cross linking which is responsible for tensile strength of the scar.

43. Complications of wound healing • Infection • Implantation cyst • Pigmentation • Deficient scar formation • Incisional hernia • Hypertrophied scars and Keloids • Excessive contraction • Neoplasia

44. Factors influencingwound healing • Local Factors • Systemic Factors

45. Local Factors • Infection • Presence of necrotic tissue & foreign body • Poor blood supply • Venous or lymph stasis • Tissue tension • Haematoma • Large defect or poor apposition

46. Local Factors (Contd) • Recurrent trauma • X-ray irradiated area • Site of wound eg. Wound over joints • Underlying diseases like osteomyelitis & malignancy • Mechanism & type of wound – incised/lacerated/crush/avulsion • Tissue hypoxia

47. General Factors • Age, obesity, smoking • Vitamin deficiency( Vit C, Vit A) • Anaemia • Malignancy • Uraemia • Jaundice • Diabetes, metabolic diseases • HIV & immunosuppresive diseases • Steroids & cytotoxic drugs

48. MANAGEMENT OF WOUNDS INCISED WOUND – Primary suturing is done after thorough cleaning LACERATED WOUND – Wound is excised & primary suturing done CRUSHED WOUND – Wound debridement, suturing after 2 to 6 days

49. Types of Suturing • PRIMARY SUTURING – means suturing the wound immediately within 6 hours. Done in clean incised wound. • DELAYED PRIMARY SUTURING – means suturing the wound in 48 hours to 10 days. Done in lacerated wound. • SECONDARY SUTURING - means suturing the wound in 10 to 14 days or later. Done in infected wounds.

50. Hypertrophic Scars and Keloids • The natural response to injury involves several stages of wound healing, migration of macrophages, neutrophils, and fibroblasts and the release of cytokines and collagen in an array to promote wound healing and maturation. • Hypertrophy and keloid formation are an overactive response to the natural process of wound healing.