Principles of Wound Management Abdelrahman S-E Imbabi, FRCSEd Assistant Professor of Surgery University of Khartoum

2Principles of Wound Management Traumatic Wounds n Usually untidy – Damage to tissues is extensive, and extent unclear – such as gunshot or blast injuries, crush injuries, lacerations or burns n And contaminated – Most traumatic wounds are potentially contaminated, and hence likely to be infected

3Principles of Wound Management Wound healing n Healing involves many humoral, chemical, environmental and cellular factors n The process may be considered as occurring in three overlapping phases

4Principles of Wound Management Phases of healing n Phase I: – Vasodilatation of capillaries in wound edges and migration of plasma, leucocytes and macrophages into the wound space n Phase II: – Development of granulation tissue, a vascular and cellular tissue comprising new vascular endothelium, fibroblasts, macrophages and mast cells n Phase III: – Remodeling; the wound assumes the appearance of an avascular fibrous scar

5Principles of Wound Management Building blocks of healing n Collagen – Synthesized within fibroblasts, extruded as soluble fibrils which become insoluble, thicker and tougher due to intermolecular cross-links n Proteoglycans – Large protein polysaccharide complexes also synthesized by fibroblasts during the 2 nd phase, responsible for stabilization and maturation of collagen n Fibronectin – Polymorphic glycoprotein, synthesized by fibroblasts during 2 nd phase and form an immobile mesh for cell- to-cell and cell-matrix adhesion

6Principles of Wound Management Chemical factors n Platelets, leucocytes, mast cells and the complement system release – Histamine – Serotonin – Kinins (bradykinin and kallidin) – Prostaglandins – Connective-tissue activating peptide – The epidermal growth factor (urogastrone) – And other factors

7Principles of Wound Management Chemical factors n These factors are directly involved in the healing process by inducing – vasodilatation, – capillary engorgement – and increased vascular permeability, n thus stimulating the synthesis of – granulation tissue, – immigration of leucocytes – and activation of wound fibroblasts

8Principles of Wound Management The fibroblast n Fibroblasts are activated by macrophages and platelet factors n They produce collagen, fibronectin and the proteoglycans of ground substance n Specialized fibroblasts (myofibroblasts) are responsible for wound contraction in secondary healing

9Principles of Wound Management The wound environment n The wound space is acidotic and hypoxic n Fibroblast proliferation and collagen synthesis occur only in areas of superior oxygenation

10Principles of Wound Management Epithelial repair n Urogastrone (epidermal growth factor) stimulates mitosis n New epithelial cells migrate until they come into contact with other epithelial cells (contact inhibition) n Hair follicles, sweat glands and sebaceous glands contribute to the repair by providing epithelial pools

11Principles of Wound Management Healing by secondary intention n Healing by secondary intention involves – laying down of excessive granulation tissue and collagen, – with contracture of up to 40-80% of the wound surface, – and re-epithelialization from the edges of the wound

12Principles of Wound Management Aim of managing wounds n To obtain healing by primary intention – Quick and easy – Smaller scars – Less contracture and deformity – Better looking

13Principles of Wound Management Healing of untidy wounds n With untidy or infected wounds, loss of tissue is extended, and primary healing cannot be achieved n Such wounds heal by secondary intention – Prolonged and complicated healing process – Involves much fibrous tissue and scarring – Gross contractures and deformity – Ugly appearance

14Principles of Wound Management Dealing with untidy wounds n The prime aim is to convert untidy and contaminated or infected wounds to tidy clean wounds which can heal by primary intention

15Principles of Wound Management How can this be achieved n All dead and devitalized tissues MUST BE REMOVED n All dirt and gross contamination should be physically washed out, or picked up by forceps n Avoid further injury to surrounding healthy tissues

16Principles of Wound Management How can this be achieved

17Principles of Wound Management Wounds less than 6 hours n Generally, wounds less than 6 hours old may be closed primarily (preferably with drain), however, it is safer practice to leave the wound open, and re-evaluate after 3-5 days, whence if the wound is clean perform a delayed primary closure. n Broad spectrum antibiotic cover n Anti-tetanus prophylaxis

18Principles of Wound Management Wounds more than 6 hours n For wounds older than 6 hours, or there is evidence of gross infection, or vitality of surrounding tissues is in doubt: – Keep the wound open – Take culture swabs and start broad spectrum antibiotics, modified later according to culture and sensitivity – Anti-tetanus prophylaxis – Re-evaluate the wound daily and debride as necessary (may require more frequent dressings)

19Principles of Wound Management Then what ? n If loss of tissues prevents non-tense primary closure, then preferably resort to either: – Skin grafting Skin grafting – Local or distant flaps, with or without muscle Local or distant flaps – Combination of muscle flap with skin grafting

20Principles of Wound Management What else ? n For proper wound healing: – Surrounding tissues must be well vascularized, hence good debridement down to bleeding tissues – Adequate oxygenation, hence improve tissue perfusion and oxygen-carrying capacity – Moisture; dehydration kills cells and tissues – Balanced nutrition with positive nitrogen balance and calories – Non-compromised immune system

21Principles of Wound Management