Acute Compartment Syndrome Flashcards
What is acute compartment syndrome?
Acute Compartment Syndrome is defined as raised pressure within an enclosed fascial space leading to localised tissue ischaemia. This may result in temporary or permanent damage to muscles and nerves.
Outline the epidemiology of ACS
Acute compartment syndrome is most common in the lower limb, and occurs in 4% of tibial fractures. It is more common in males than females, and the young rather than old (young man > old woman).
What is the pathophysiology of ACS?
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 reduced when the pressure exceeds systolic blood pressure.
When the mean arterial pressure entering a compartment falls below that of the compartment ischaemia will begin to occur.
What is the most common cause of ACS?
70% cases caused by fracture
Give 6 causes of ACS other than fracture
- Crush syndrome
- Bleeding disorder (Haemophillia A/B), anti-coagulants
- Soft tissue injury
- Re-perfusion injury
- Infection
- Iatrogenic
What sites are usually affected?
The upper and lower limbs are most affected, as they have the most compartments – however other regions, such as the abdomen and gluteal regions, can be affected.
Outline the Forearm compartments and structures at risk
- Ventral compartment: median and ulnar nerves; radial and ulnar arteries.
- Dorsal compartment: posterior interosseous nerve; no major vessels.
Outline the lower limb compartments and structures at risk
- Ventral compartment: median and ulnar nerves; radial and ulnar arteries.
- Dorsal compartment: posterior interosseous nerve; no major vessels.
What is gluteal compartment syndrome?
- Uncommon and is often diagnosed late, resulting in muscle necrosis and sciatic nerve palsy.
Who does abdominal compartment syndrome usually occur oin?
multiple trauma patient who has undergone a period of profound shock.
What are the key history & examination signs in ACS? Four of them
- Pain
- Tense, swollen compartment
- Paraesthesiae/hypoaesthesiae
- Pulses rarely absent
What are the characteristics of pain in ACS
Excessive/progressive/not relieved by analgesia/passive stretch pain
What are the 6 P’s of compartment syndrome?
- Pain
- Pulselessness
- Pallor
- Paralysis
- Paraesthesia
- Perishingly cold
Why are the 6 Ps useless?
Compartment syndrome should be picked up before these signs occur
How can diagnosis of ACS be made?
Diagnosis can be made clinically or on the basis of compartment pressure monitoring
What are the two main criteria for diagnosis ACS from compartment pressure monitoring?
- Pressure >40mmHg
OR - Pressure differential 30mmHg below diastolic blood pressure – especially important in the hypotensive patient!
What investigations can be made into ACS?
Intracompartmental pressure can be measured through using a wick catheter, needle manometry or side-ported needles. MRI scans can help in clinically ambiguous situations.
What is the treatment for ACS?
Immediate surgical decompression is required on the recognition of ACS via a dermatofasciotomy. This may or may not involve debridement of necrotic tissue, skeletal stabilisation and treatment of an underlying cause.
Skin and deep fascia must be divided along the whole length of the compartment.
All potentially constricting dressing must be removed
Give four complications of ACS
- Muscle necrosis
- Joint stiffness
- Nerve fibrosis
- Delayed fracture union
What occurs in ACS muscle necrosis?
Muscle necrosis can lead to fibrosis and shortening, resulting in ischaemic contracture and weakness.
Give compartments of lower limb and incisions needed
Lower limb – 4 compartments - Anterior - Lateral - Deep posterior - Superficial posterior Two incisions, medial and anterolateral.
Give compartments of thigh and incisions needed
Thigh – 3 compartments - Anterior - Medial - Posterior Two incisions, lateral and posterior (+/- medial)
Give compartments of foot and incisions needed
Foot – 4 compartments - Medial - Central - Lateral - Interosseous Three incisions, anteromedial, medial dorsal and lateral dorsal
Give compartments of forearm and incisions needed
Forearm – 3 compartments - Palmar/flexor - Dorsal/extensor - Radial Two incisions, long palmar, dorsal, +/- carpal tunnel decompression
Give compartments of handand incisions needed
Hand – 10 compartments - 4 dorsal interosseous - 3 palmar interosseous - Add. Pollicis - Thenar - Hypothenar Four incisions made
What are the five aspects of post-operative management of ACS?
- Leave wounds open
- Use loose, absorbent dressings
- Elevate gently
- Maintain fluid balance and adequate analgesia
- Reinspection +/- debridement +/- delayed closure at 2-5 days
What is the prognosis of ACS?
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.
