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#Compartments of lower leg skin#

It is tempting to the surgeon to try early secondary skin suture, rather than skin-graft coverage, once the swelling has subsided. The simplest and safest technique is to cover the healthy soft-tissue defect with a split skin graft: at a later date, when the limb contours have returned to normal, the grafted area can be excised and secondary skin closure performed without tension. Once any skeletal injury is under control, the fasciotomy wound(s) healthy and the swelling of the soft tissues has sufficiently regressed, consideration must be given to achieving skin coverage. Reperfusion injury is another cause of compartment syndrome. After blood flow is restored, capillaries leak and ischemic muscle swells.

An arterial injury may cause compartmental tissue ischemia.

Muscle tolerates short periods of hypoxia, but after a few hours, progressive necrosis begins.

(MPP has also been called "Delta P", to indicate the difference between diastolic blood pressure and intramuscular pressure.) This difference in pressure reflects tissue perfusion far more reliably than the absolute intramuscular pressure.

The critical measurement is muscle perfusion pressure (MPP), the difference between diastolic blood pressure (dBP) and measured intramuscular tissue pressure.

if diastolic arterial pressure is not more than 30 mm Hg above tissue pressure, compartmental capillary blood flow is significantly obstructed and severe hypoxia occurs in muscle and nerve tissue.

When tissue pressure approaches the diastolic pressure, capillary blood flow ceases. The capillary filling pressure is essentially diastolic arterial pressure.

This critical level is the tissue pressure which collapses the capillary bed and prevents low-pressure blood flow through the capillaries and into the venous drainage. Compartment syndrome occurs when the pressure within a closed osteo-fascial muscle compartment rises above a critical level.