Compartment Syndromes

Compartment syndrome is caused by an elevation of interstitial pressure in a closed fascial compartment. It can occur wherever a compartment is present. Therefore although the upper and lower limbs are most commonly affected, other sites may be affected, particularly the abdomen and gluteal regions:

• With increasing duration and magnitude of interstitial pressure, there is increasing impairment of muscle and nerve function and necrosis of soft tissues
• Initial venous compromise may progress to reduced capillary flow, which increases ischaemia and may further increase the interstitial pressure, leading to a vicious cycle of increasing pressures
• Arterial blood inflow is rarely reduced unless the pressure exceed systolic blood pressure

• Ventral compartment: median and ulnar nerves; radial and ulnar arteries
• Dorsal compartment: posterior interosseous nerve; no major vessels.

• Anterior tibial compartment: deep peroneal nerve; anterior tibial artery
• Superficial posterior compartment: no major nerves or vessels
• Deep posterior compartment: posterior tibial nerves and vessels; peroneal artery
• Peroneal compartment: deep and superficial peroneal nerves.

• Uncommon and is often diagnosed late, resulting in muscle necrosis and sciatic nerve palsy
• The mainstay of treatment is prompt diagnosis and early surgery.

• May occur in any multiple trauma patient who has undergone a period of profound shock
• It may cause acute renal failure, cardiac dysfunction and an elevated central venous pressure
• The diagnosis can be confirmed by the measurement of intra-abdominal pressure, either by a foley catheter in the bladder or a nasogastric tube in the stomach
• Sudden release of the abdominal compartment syndrome may lead to an ischaemia-reperfusion injury causing acidosis, cardiac dysfunction and cardiac arrest.

• Fractures: especially fractures of the forearm and lower leg that have been internally fixed or infected
• Crush injury
• Burns
• Infection
• Prolonged limb compression, e.g. immobilisation in a tight plaster cast
• Vascular: ischaemia-reperfusion injury, haemorrhage, phlegmasia caerulea dolens
• Iatrogenic: intramuscular injections, vascular puncture in anticoagulated patients
• Muscle hypertrophy in athletes.¹

Compartment syndrome may complicate up to 15% of open fractures.

Compartment syndromes usually present within 48 hours of injury. A high index of suspicion is required, especially with an unconscious patient following major trauma. Clinical features include:

• Increasing pain despite immobilisation of fracture
• Sensory deficit in the distribution of nerves passing through the compartment
• Muscle tenderness and swelling
• Excessive pain on passive movement, increasing pain despite immobilisation
• Peripheral pulses may still be present
• Later features are of tissue ischaemia with pallor, pulselessness, paralysis, coolness and loss of capillary return.

Any other cause of limb swelling, e.g. peripheral oedema, deep vein thrombosis.

• Diagnosis is essentially clinical with recognition of patients at risk and recognition of early signs
• Intracompartmental pressure can be measured by several methods including Wick catheter, needle manometry, infusion techniques, pressure transducers or side-ported needles
• The critical pressure for diagnosing compartment syndrome is unclear
• MRI scans help make the diagnosis of compartment syndrome in clinically ambiguous cases².

Patients with a swollen limb and no clear underlying cause should be considered for urgent orthopedic opinion³.

• Urgent decompression is required to prevent severe ischaemia. Early orthopaedic referral and continuous compartment pressure monitoring is required
• All potentially constricting dressings, casts and splints must be removed. Splitting a plaster is not sufficient. The compartment pressure should be measured
• Open fasciotomy:
• Indications for fasciotomy vary between different authorities, e.g. absolute compartment pressure greater than 30-40 mmHg; difference between diastolic pressure and compartment pressure greater than 30 mmHg or difference between mean arterial pressure and compartment pressure greater than 40 mmHg
• The skin and deep fascia must be divided along the whole length of the compartment
• Otherwise, the limb should be closely observed until improvement is apparent clinically. If no improvement occurs then a fasciotomy is required. All four compartments may need to be opened in cases involving the leg
• After fasciotomy, the wound should be left open. Healing may be encouraged by suturing, skin grafting or the wound left to heal by itself
• Debridement may be indicated for any muscle necrosis.

• Tissue necrosis develops within about 12 hours
• Muscle necrosis leads to fibrosis and shortening, resulting in an ischaemic contracture (Volkmann's ischaemic contracture).

• Nerve dysfunction may be reversible with time but infarcted muscle is damaged permanently
• Early surgery enables a good functional outcome but delay results in muscle ischaemia and necrosis.