Wound Healing PDF

Wound healing Dr SALAH SHAHEEN Prof of General Surgery Kasr Al-Ainy Hospital, Cairo university A wound is defined as a breakdown of the tissue continuity. Etiology ❑ Trauma including surgery. ❑ Caused by Sharp object e.g. scalpel, broken glass,...

Wound healing Dr SALAH SHAHEEN Prof of General Surgery Kasr Al-Ainy Hospital, Cairo university A wound is defined as a breakdown of the tissue continuity. Etiology ❑ Trauma including surgery. ❑ Caused by Sharp object e.g. scalpel, broken glass, sharp metal like a knife…etc (cut wound) Blunt object e.g. stick, collision with car, fall from a height…etc (contused wound) Pointed object e.g. nail, metallic rod (penetrating or puncture wound) Others e.g. bullet, missile, blast, stab, bite Types of wounds 1) Incised (clean, cut or tidy) wounds. 2) Lacerated (contused or untidy) wounds. 3) Puncture (penetrating) wounds. 4) Others (including abrasions, contusions, hematoma, bites, missile and blast injuries. Tidy wound Untidy wound Phases of wound healing 1) Phase of inflammation “Lag phase” (Day 1– 4) 2) Phase of granulation tissue “Proliferation phase” (Day 5-20) 3) Phase of scar formation “Maturation and remodeling phase” (Day 20 onwards) 1) Phase of inflammation (Lag phase)  Hemostasis leading to platelets plug.  Platelets release certain cytokines and growth factors that stimulate chemotaxis of leucocytes and macrophages.  Macrophages → phagocytosis and wound debridement. Also, they release further growth factors → recruitment and activation of fibroblasts and endothelial cells i.e. to start granulation tissue formation. 2) Phase of granulation tissue (proliferation phase)  Fibroblasts (derived from the surrounding tissues) secrete collagen.  Endothelial cells (proliferating from intact venules in the area) form new capillary buds.  Both capillary buds and fibroblast form granulation tissue that fill the gap.  Epithelial cells proliferate from wound edges to cover granulation tissue. 3) Phase of scar formation (maturation & remodeling phase)  Immature collagen becomes mature.  Collagen fibers are arranged along lines of tension → ↑ tensile strength of the wound.  This phase is prolonged up to 1 – 2 years (don’t revise a scar before 1 y). Components of wound healing  Wound contraction to diminish wound size.  Granulation tissue formation Later replaced by fibrosis  Epithelization Types of wound healing  Healing by primary intention – Occurs in clean wounds when immediately closed by sutures. – There is minimal fibrosis leading to a nice neat scar.  Healing by secondary intention – Occurs when the wound edges cannot be approximated due to presence of devitalized tissue, infection or skin loss. – Healing occurs slowly by in-filling with granulation tissue with resulting more fibrous tissue. – This ends in an unsightly or ugly scar. Treatment ❑ General management of the injured patient i.e. maintenance of adequate airway, breathing and circulation. ❑ Stop bleeding, if there is. ❑ Prophylaxis against tetanus. ❑ Prophylactic antibiotics contaminated, deep or lacerated wounds. ❑ In theater, – Thorough cleaning of the wound by saline irrigation. – Sterilize the wound and surrounding skin by an antiseptic solution, e.g. povidone iodine (Betadine). – Meticulous removal of foreign bodies and dead tissue. Treatment  Explore the wound to assess extent of damage. Extension on both sides to help complete exploration in punctured wounds may be needed.  Incised wounds are ideal for primary closure if done within 6 hours of injury. Damaged nerves, vessels and tendons should be repaired  Lacerations are treated by thorough wound toilet with warm saline solution, wound excision and primary closure if done within 6 hours of injury. If treatment is delayed, debridement is done, and the wound should be left open to be repaired after few days (delayed primary repair). Nerve or tendon repair is better to be deferred.  In case of gross sepsis, the wound is left open and treated with regular dressing and antibiotics. It takes around 2 weeks to become clean. Closure of the wound at this stage is called as secondary suturing.  Skin loss is treated by a skin graft or flap when wound becomes clean. Wound excision Factors affecting wound healing General factors  Age; healing is slow in elderly persons.  Nutritional status; hypoproteinemia leads to diminished synthesis of collagen and ground substance. Vitamin C deficiency → lack of maturation of collagen. Vitamin A deficiency → deficient epithelization. Anemia delay wound healing.  Debilitating diseases as uremia, jaundice, cirrhosis, diabetes and malignancy delay wound healing.  Drug intake: Corticosteroids and cancer chemotherapy inhibit wound healing. Factors affecting wound healing Local factors  Wound infection.  Poor blood supply (face and scalp have rich blood supply vs poor blood supply below knee). Radiotherapy causes local endarteritis obliterans leading to ischemia and poor healing.  Foreign bodies or necrotic tissue in wound.  Wound factors e.g. hematoma, tension on suture line, faulty wound closure and lack of rest to the sutured area, all delay wound healing.  Fixation to the underlying bone prevents wound contraction. Complications of wound healing 1) Wound infection. 2) Wound dehiscence (gapping). 3) Hypertrophic scar: scar is red, raised, itchy and tender usually up to 6 months and then gradually regresses (actually, it is a stage in healing). 4) Keloid formation 5) Contractures: Shortening of the scar → deformity if scar is over a joint. 6) Malignant transformation (Marjolin’s Ulcer). Hypertrophic scar Keloid Thank You