Impaired wound healing may be attributed to defects in the normal tissue response to injury and to poor treatment of the wound. Chronic wounds are defined as those that do not appear to follow the normal healing process in less than 4 weeks. These wounds are most commonly located on the lower leg, foot, and pelvic region. Healing is more difficult because the aetiology of the wound is harder to determine, and the measures to reverse the medical abnormalities are often complex.
Impaired wound healing
Many intrinsic and extrinsic factors can impair wound healing.
Local factors
- Growth factors
- Oedema
- Ischaemia
- Hypoxia
- Infection
Regional factors
- Arterial insufficiency
- Venous insufficiency
- Neuropathy
Systemic factors
- Inadequate perfusion
- Metabolic disease
Miscellaneous factors
- Nutritional state
- Pre-existing illness
- Exposure to X-radiation
- Smoking
- Drugs
Smoking
The association between poor surgical outcome and smoking has been recognised for a long time. Smoking increases the risk of wound infection, graft or flap failure, tissue necrosis and haematoma formation. The pathogenesis is unclear but involves:
- Arteriolar vascoconstriction and cellular hypoxia
- Decreased collagen synthesis
Treatment
Treatment of wound infection.
An infected wound must be cleansed and debrided to remove necrotic tissue and foreign bodies. Techniques include:
- Surgical debridement
- Topical enzymes
- Moisture-retentive dressings
- Biosurgical therapy (maggots etc)
- Negative-pressure wound therapy (also called vacuum assisted closure or VAC).
Treatment with topical antibiotics is popular but undesirable because of increasing rates of bacterial resistance. Current interest is focused on antimicrobial moisture-retentive dressings, honey, essential oils and cationic peptides.
More serious local and systemic infections should be treated with systemic antibiotics: penicillins, cephalosporins, aminoglycosides, fluoroquinolines, and sulfonamides are most often prescribed. Other antibiotics include clindamycin, metronidazole, and trimethoprim.
