Involves point scales for degree of skin, nerve, vascular and bone injury, and for injury severity, age, concurrent medical conditions, and time to vascular repair. This system is complex and subjective, with many variables requiring surgical intervention for accurate determination. Again, much information must be obtained by surgery. This system is based on the degree of skeletal and soft tissue injury, ischaemia, shock and age. MESS is simple to apply and has been validated with a prospective study.
Most information required is available at initial evaluation, although some factors are subjective.
When applied to the upper extremity, MESS accurately predicts amputation and is useful as an objective aid to augment clinical experience. LSI is based on duration of ischaemia and severity of injury to artery, bone, muscle, skin, nerve and deep veins. The system is very detailed, requiring operative evaluation for accurate scoring, with some scores requiring treatment and outcome to be known initially. No studies have validated this system. Most studies evaluating these systems are retrospective and involve small numbers of patients, so are subject to error.