Expansion
Local factors at the wound, systemic factors in the patient
Expansion
Local factors, at the wound itself
- Infection, the commonest cause of delay
- Ischaemia and poor perfusion
- Foreign body, necrotic tissue, haematoma
- Movement and mechanical stress
- Radiation damage
- Poor apposition, excess tension
Systemic factors, in the patient, remembered as DIDN’T HEAL:
- D - Diabetes
- I - Infection
- D - Drugs: corticosteroids, chemotherapy, NSAIDs
- N - Nutritional deficiency: protein, vitamin C, zinc
- T - Tissue necrosis
- H - Hypoxia and anaemia
- E - Excess tension
- A - Another wound, or malignancy
- L - Low temperature, and Liver or renal failure
“Vitamin C for collagen, zinc for epithelialisation, protein for everything.” Vitamin C is required for proline and lysine hydroxylation in collagen synthesis, which is why scurvy causes old wounds to break down.
Healing by primary intention is a clean apposed wound with minimal granulation tissue and a fine scar; secondary intention is an open wound healing by granulation, contraction and epithelialisation, giving a larger scar and more contracture.
Wound strength reaches only about 70 to 80 per cent of the original, and takes about 3 months to do so.