compartment syndrome

see also:

• acute foot drop

• compartment syndrome is a surgical emergency as the increased pressures within a fascial compartment such as the lower leg compartments results in markedly reduced blood supply and progressive ischaemia and muscle and nerve infarction - muscle necrosis can occur quickly, within 3-4 hours of original injury and becomes irreversible within 4-8hrs
• first described in 1881 by Richard von Volkmann
• the lower leg has 4 major fascial compartments:
  • anterior (the most common compartment affected)
  • lateral (the 2nd most common compartment affected)
  • superficial posterior
  • deep posterior - these are easily missed!
• men are 10x more likely to develop compartment syndrome
• those with a coagulopathy are at higher risk
• occurs in 2-9% of those with tibial fractures, especially diaphyseal fractures
• occurs in 3% of those with mid-shaft forearm fractures
• Abdominal compartment syndrome occurs when the intra-abdominal pressure exceeds 20 mmHg and abdominal perfusion pressure is less than 60 mmHg. This disease process is associated with organ dysfunction and multiple organ failures.

• fracture (accounts for 75% of cases)
• muscle trauma or crush injuries
• encircling tight bandages or plasters
• eschar from burns
• extravasation of IV or IO fluids
• reperfusion following ischaemia
  • post-operative repair of arterial obstruction
  • prolonged compression of artery - intoxicated states, decreased mental state
• anabolic steroid use
• acute strenuous muscle use eg. horse riding for the first time
• hypothyroidism
• snakebites
• Chronic (Exertional) Compartment Syndrome - generally does not cause permanent damage

• pain more severe than expected and not relieved by rest or non-steroidal anti-inflammatory drugs (NSAIDs)
• stretching the muscles increases the pain
• +/- paraesthesae of skin
• muscle may feel tight, “wooden” or full
• distal pulses may be diminished but will usually still be present unless there is peripheral vascular disease (PVD or PAD) as well
• numbness or paralysis is usually a late sign and indicates permanent injury
• if not treated within 6 hours, permanent injury will occur which may later result in gangrene, Volkmann's contracture, and chronic regional pain syndrome
• almost a quarter develop rhabdomyolysis

• may be confirmed by measuring compartment pressures
  • a transducer connected to a saline filled IV fluid catheter connected to a 18G needle is inserted 5 cm into the zone of injury
  • normal pressure within the compartment is between 0 mmHg to 8 mmHg
  • The perfusion pressure of a compartment, also known as the compartment delta pressure, is defined as the difference between the diastolic blood pressure and the intra-compartmental pressure
  • pressures higher 30mmHg (20mmHg if hypotense) or a delta < 30mmHg indicate compartment syndrome
• XR to exclude other causes of pain such as undiagnosed fractures
• if pulses are absent then emergent angiogram may be indicated
• consider Doppler USS if DVT is more likely and compartment pressures are normal
• serum CK to assess for rhabdomyolysis
• MRI can be used to Dx Chronic (Exertional) Compartment Syndrome

• remove any encircling dressing or plaster cast including any underpadding
• supplemental oxygen
• elevate the extremity to levl of heart to improve perfusion
• avoid hypotension
• immediate surgical consult
• manage any rhabdomyolysis to prevent acute kidney injury (AKI) / acute renal failure (ARF)
• if intracompartmental pressures are elevated but below the threshold for fasciotomy, consider serial measurements
• urgent fasciotomy if less than 36hrs from onset and acute compartment syndrome
  • ideally within 6hrs of onset
  • of no benefit after 36hrs as just adds risk of infection ¹⁾
  • if chronic then an elective fasciotomy may suffice