Compartment syndrome is a serious, life-threatening condition that develops in the compartment of the extremities. The compartments refer to the osteofascial compartment which contains muscles, blood vessels and nerves, all enclosed within the fascia. It is serious as it leads to acute ischaemia of the limb.
The compartment we're dealing with here is the osteofascial compartment, which includes muscle, blood vessels and nerves enclosed within fascia (fibrous connective tissue).
Pathophysiology
The osteofascial compartments contain muscles, vessels, nerves and are surrounded by fascia. In compartment syndrome there is a rise of the pressure within the compartment due to oedema, haemorrhage, extravasation of fluids, swelling of muscle, external compression. This pressure increase leads to compression of the microvasculature within the compartment which leads to ischaemia of tissue. As this ischaemia progresses, tissue necrosis may occur which leads to interstitial oedema development. This further worsens the compartmental swelling. There is irreversible damage 4-6 hours after onset of ischaemia.
Let’s discuss some of the common causes of acute compartment syndrome:
- Fractures - this makes up 70% of cases. Tibial shaft fracture is the most common cause, making up up to 40% of all compartment syndrome cases.
- Ischaemia-reperfusion - reperfusion of ischaemic tissue leads to ROS and inflammatory mediator release that subsequently leads to oedema accumulation.
- Extremity compression - due to constrictive bandaging or casting or prolonged immobilisation.
- Burns
- Iatrogenic - such as extravasation of fluids, intramuscular injections, and anticoagulation.
- Muscle hypertrophy
Causes of external compression | Causes of internal compression | |
Trauma-related causes | • Burn eschars
• Constrictive bandage/cast applied before the limb has stopped swelling | • Haematoma and oedema from long bone fractures
• Haemorrhage (especially arterial injuries) into muscle compartment
◦ Penetrating injuries (e.g., gunshot, stab wounds, iatrogenic radial artery perforation)
◦ Crush injuries with deep tissue injury
• Reperfusion syndrome with ischaemia-reperfusion oedema
• Burn oedema
• Oedema from venomous animal bites (especially snake bites)
• Extravasation of IV infusion
• Repetitive muscle use (esp. excessive running, seizures) |
Non-trauma-related causes | • Prolonged poor positioning of limbs (ie surgery) | • Increased capillary permeability (e.g., due to shock)
• Spontaneous bleeding in coagulopathic patients |
Let’s quickly look at some of the sites that may be affected
- Forearm compartment syndrome
- Ventral compartment - contains median and ulnar nerves as well as radial and ulnar arteries.
- Dorsal compartment - contains posterior interosseous nerve.
- Gluteal compartment syndrome - may result in sciatic nerve palsy.
- Lower limb compartment syndrome
- Anterior tibial compartment - contains the deep peroneal nerve and anterior tibial artery.
- Superficial posterior compartment - contains no major nerves or vessels.
- Deep posterior compartment - contains the posterior tibial nerves, posterior tibial artery and peroneal artery.
- Peroneal compartment - contains the deep and superficial peroneal nerves.
- Hand compartment syndrome
- Foot compartment syndrome
😷 Presentation
Signs and symptoms typically progress very rapidly and over a few hours of an injury.
- Early features:
- ⭐️ Pain - disproportionate to the underlying injury. It is worsened by passive stretching of the muscles. It is felt deep and is described as a burning pain. It is extremely tender to touch and is poorly localised. The pain is refractory to opioid painkillers even.
- Tight wood-like muscles
- Swollen limb
- Late features:
- Paraesthesias
- Paralysis (a late and worrying feature)
- Pallor
- Pressure (high pressure)
- Sensory deficits
- Pulses remain detectable - except in very severe cases of compartment syndrome. Pulsatility should not be used to exclude diagnosis.
🔍 Investigations
⭐️ The diagnosis is clinical, but is typically confirmed with early measurement of compartment pressures.
- 🥇 Compartment pressure measurement - via needle manometry. This device injects saline through the needle compartment and in turn measures the resistance to it. It is indicated if there is uncertainty of the diagnosis or the patient is deemed at risk of compartment syndrome.
Normal compartment pressure is 0-8mmHg. Any pressure between 20-30mmHg is at high risk for compartment syndrome and may need fasciotomy but definitely requires monitoring. If the pressure is >40mmHg it is diagnostic and requires urgent surgical decompression.
Other investigations may include:
- Serum CK - elevated as it indicates muscle cell lysis and muscle necrosis.
🧰 Management
- 🥇 Dressing release - if due to compressive bandaging or casting.
- 🥇 Fasciotomy - if due to internal compressive causes. It should be performed within an hour of the decision to operate and ideally should be done prior to 4 hours of onset.
- 🥈 Amputation - if the limb is not viable due to significant muscle necrosis.
Fasciotomy involves incisions of the fascia down to the entire length of the compartment to release the pressure. It is important to explore the compartment and debride any necrotic muscle tissue. The wound is then left open and covered with a dressing. The swelling should subsequently improve and the wound may gradually be closed (but this may occur over several weeks). A graft may be required if the wound cannot be closed.
Other aspects of management that are vital include:
- Fluid therapy - as myoglobinuria may occur leading to acute kidney injury.
💡 If there is chronic compartment syndrome (also known as exertional compartment syndrome) then management involves limiting exertional activities that evoke the onset. If they are unable to do so (e.g. athletes), fasciotomy may be used. NSAIDs can also be implemented to limit pain.
🚨 Complications
- Acute kidney injury
- Tissue necrosis and limb loss
- Volkmann’s ischaemic contracture - this is when muscle necrosis leads to fibrosis which then causes shortening and contractures of the limb.