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Surgical/excisional debridement involves removal of non-viable tissue using scalpel, forceps, scissors or laser. Biological/maggot therapy debridement involves the use of sterile larvae, which are applied to the wound. Secretions from these larvae selectively degrade necrotic tissue, reduce microorganism load and promote granulation. One shortcoming is that maggots cannot penetrate hard, dry eschar. Table 1.2. Factors affecting wound healing. Local factors Systemic factors Infection Age and sex Foreign body Sex hormones Poor oxygenation Stress Venous insufficiency Ischaemia Diseases: diabetes, keloids, fibrosis, jaundice, uraemia, obesity Medications: steroids, NSAIDs, chemotherapy Alcohol and smoking Immunocompromise: cancer, radiotherapy, AIDS Malnutrition 10 Textbook of Plastic and Reconstructive Surgery 4.2. Infection and inflammation The early stages of wound healing involve inflammation as a normal part of the process. This is characterised by heat, redness, swelling and pain. Inflammation can also be indicative of a bacterial burden anywhere along the spectrum of contamination > colonisation > critical colonisation > infection. In contaminated wounds, low numbers of non-replicating bacteria are present. In colonised wounds, replicating bacteria are present without stimulating an inflammatory reaction. In critically colonised wounds, large numbers of bacteria cause delayed wound healing. Infection is caused by the invasion of wound tissue by an even greater number of bacteria, which subsequently stimulate an inflammatory reaction. The type and extent of infection is determined by the causative microorganism, its load and the host’s ability to fight it. This information is commonly sought from wound cultures; however, the gold standard in microbial analysis is tissue biopsy. Non-healing and chronic wounds require multiple modalities of treatment for successful healing.