Pressure sores have defied the best attempts of medical and nursing staff since they were first described in Egyptian mummies.1 They are defined as a localised area of tissue damage resulting either from direct pressure on the skin causing pressure ischaemia or from shearing forces causing mechanical stress to the tissues. The pathophysiology remains poorly understood.2

Pressure sores are painful, unsightly, difficult to treat, and costly. The estimated cost of caring for pressure sores is pounds sterling 150 million a year in the United Kingdom and more than $3 billion in the United States.3, 4 A full thickness sacral sore typically involves substantial expenditure in staff time, dressing materials, drugs, and special pressure relieving beds during hospital inpatient care over many months; the estimated total cost per patient is pounds sterling 26 000.5 Also, there is the cost to patients in lost income, productivity, and independence, which the patients and their relatives increasingly attempt to recover from health authorities by litigation.6, 7