Compartment Syndrome

 

Definition of compartment syndrome

• The condition where elevated pressure within a confined space can lead to damage of its contents
• This can occur in other areas of the body (e.g. abdominal compartment syndrome, raised intracranial pressure) but in this situation it refers to the elevation of pressure within a discrete myofascial compartment leading to irreversible injury to its contents (particularly muscles and nerves)

 

Epidemiology of compartment syndrome

• Compartment syndrome is most common in patients under 35 years of age, with a gender preponderance towards men, often following fractures of the tibial diaphysis
• It is most often seen in the leg, followed by the forearm
• It can also affect the hand and foot and rarely the upper arm or thigh

 

Causes of compartment syndrome

• Extraneous forces that constrict the size of the compartment
  • Closure of fasical defects
  • Tight plaster casts
  • compression bandages
  • Pneumatic anti-shock garments or burns
• Intrinsic changes that alter the compartment’s contents
  • Haemorrhage following soft tissue injury/fracture
  • Post-operative swelling and oedema
  • Post-ischaemic swelling
    • e.g. after tourniquet use intraoperatively or in pre-hospital care

 

Presentation of compartment syndrome

• The ‘six Ps’ are often stated as the diagnostic criteria for compartment syndrome
  • Pain, pallor, pressure, paraesthesiae, paralysis and pulselessness
    • Although they are often present, if one waits for these to develop (particularly paralysis and pulselessness) it is most likely too late
• The first sign, in an alert responsive patient without distracting injury, is pain out of proportion to the injury
• On examination, the most reliable sign is severe pain on passive stretch of the involved muscles within the affected compartment.
  • One can also see that the compartment in question is also swollen to a high intensity.

 

Video on diagnosis and treatment of compartment syndrome

 

Differential diagnosis of compartment syndrome

• Deep vein thrombosis
  • Due to the similar presentation with pain and swelling in the lower leg
• Cellulitis
  • Presenting with pain and often lower-limb swelling. Check for temperature and inflammatory markers.
  • There should not be pain on passive stretch of muscles.
• Peripheral vascular disease/ischaemic limb
  • These are included together as they are part of a spectrum of disease. They often present with the 4 Ps due to inhibition of blood supply, but the compartment is often soft and there is often coexisting vascular disease.
• Septic Arthritis
  • This can often present with excruciating lower limb pain with swelling
  • Look for raised inflammatory markers, pyrexia or a joint effusion to differentiate between this and compartment syndrome.
• Rhabdomyolysis
  • This also often follows trauma. It also presents with muscle pain but also a picture of more generalised malaise
  • Look for dark urine, deteriorating renal function and raised creatinine kinase
  • Consultant a renal physician if acute renal failure in this context

 

Diagnosis of compartment syndrome

• Compartment syndrome is a clinical diagnosis on the basis of the above clinical picture together with an evaluation of the clinical likelihood.
  • It is often difficult to ascertain in those who have a reduced conscious state (e.g. intubated poly-trauma patients on ITU)
  • For this reason there are other diagnostic criteria that can be used:
• Measurement of intra-compartmental pressure
  • If the pressure exceeds 30mmHg then compartment syndrome is likely

If this exceeds 40mmHg or rises to within 20mmHg of the patient’s diastolic blood pressure (i.e. above 50 for a patient with a diastolic pressure of 70), urgent fasciotomy should be carried out as a limb/life saving measure.

 

Initial management of compartment syndrome

• Initial management centres around early appreciation of risk of compartment syndrome, together with close monitoring. Monitoring includes:
  • Pain out of proportion to injury
  • Checking compartment pressures in those unable to respond to pain
    • e.g. patients who have blocks, patients with a reduced Glasgow Coma Score
• Remove any constrictive dressings or split them down to the skin
• Hold the limb at the level of the heart (not above) to promote arterial inflow
• If there is any suspicion of compartment syndrome there should be a low threshold for urgent referral and assessment by an orthopaedic specialist
  •  They may wish to perform formal compartment pressure monitoring using specialist equipment

 

Further management of compartment syndrome

• Urgent fasciotomy
  • The release of the restrictive fascial compartment with both the skin and fascia left open to decompress the structures within
  • The skin can be grafted at a later date by a centre with a plastic surgery department

 

Complications of compartment syndrome

• If left untreated, the end result is necrosis of the muscles
• This leads to an ischaemic contracture depending on the compartment involved and loss of the movements generated by the muscle group in question
  • This is known as Volkmann’s contracture in the forearm, wherein the muscles of the flexor compartment contract resulting in a claw like deformity of the hand

 

Prognosis following compartment syndrome

• Prognosis is highly dependent on time to intervention
• If dealt with within 6 hours, with an urgent fasciotomy the outcomes are excellent
• If delayed up to 12 hours only 68% of patients have a normal limb function
• Beyond this the rates of normal limb function are just 8%

 

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