Several conditions are classified as varieties of chronic wounds, although they may not clearly follow mechanical trauma.
An ulcer is any breach in an epithelial surface. Chronic ulcers are wounds that fail to heal. In generally, they have a fibrotic margin and a bed of granulation tissue which may include areas of slough (necrotic tissue). Ulcers are particularly common in the lower third of the lower limb and foot. They have a number of different aetiologies, often being associated with arterial or venous insufficiency or a lack of normal skin innervation. The wound healing process is delayed by a variety of mechanisms including infection, mechanical irritation, ischaemia or other metabolic factors. Ulcers are common in diabetes and rheumatoid arthritis. Treatment consists of specific management of the underlying cause. The ulcer is managed either by dressings to allow healing by second intention or by surgical excision of granulation tissue and split-skin grafting. Recurrence is inevitable if the underlying cause is not corrected.
These are chronic wounds following tissue necrosis from pressure. They occur over bony prominences. Their pathogenesis is identical to compartment syndrome in that they arise where there is unrelieved pressure in the soft tissues overlying bone such that the external pressure exceeds capillary perfusion pressure and ischaemic necrosis occurs. They occur in paraplegic individuals who lack the usual sensory input that tissue ischaemia is beginning and may lack the ability to move themselves and relieve this pressure. They also occur in situations where perfusion pressure is low, such as hypotension and peripheral vascular disease. Sacral and trochanteric sores occur in bed-bound patients, both paraplegic and nonparaplegic. Ischial pressure sores occur in chair-bound paraplegics. Patients with peripheral vascular disease are prone to heel pressure sores. On occasions almost any bony prominence may be involved. Prevention is better than cure. This depends on an awareness of pressure sore risk in all patients and the implementation of appropriate measures that may include turning or lifting the patient, pressure-relieving mattresses and beds, special seating and cushions, and educating the patient and their carers in taking responsibility for pressure relief. When a sore occurs it is essential to identify and correct the underlying cause. If this can bedone most sores will heal by second intention. Incontinence should be managed appropriately and nutritional support provided if needed. Surgical treatment can accelerate healing. The sore is excised and closed using a flap. Pressure sore closure is indicated for nonparaplegics where the sore is delaying or complicating their recovery from an illness, and in paraplegics who have identified and corrected the precipitating cause and who are motivated to maintain adequate pressure relief. Surgery is usually inappropriate in those in the later stages of progressive neurological illnesses.
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