Acute Compartment Syndrome

Question 1

What is acute compartment syndrome?

Answer 1

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.

Question 2

Outline the epidemiology of ACS

Answer 2

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).

Question 3

What is the pathophysiology of ACS?

Answer 3

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.

Question 4

What is the most common cause of ACS?

Answer 4

70% cases caused by fracture

Question 5

Give 6 causes of ACS other than fracture

Answer 5

• Crush syndrome
• Bleeding disorder (Haemophillia A/B), anti-coagulants
• Soft tissue injury
• Re-perfusion injury
• Infection
• Iatrogenic

Question 6

What sites are usually affected?

Answer 6

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.

Question 7

Outline the Forearm compartments and structures at risk

Answer 7

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

Question 8

Outline the lower limb compartments and structures at risk

Answer 8

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

Question 9

What is gluteal compartment syndrome?

Answer 9

• Uncommon and is often diagnosed late, resulting in muscle necrosis and sciatic nerve palsy.

Question 10

Who does abdominal compartment syndrome usually occur oin?

Answer 10

multiple trauma patient who has undergone a period of profound shock.

Question 11

What are the key history & examination signs in ACS? Four of them

Answer 11

• Pain
• Tense, swollen compartment
• Paraesthesiae/hypoaesthesiae
• Pulses rarely absent

Question 12

What are the characteristics of pain in ACS

Answer 12

Excessive/progressive/not relieved by analgesia/passive stretch pain

Question 13

What are the 6 P’s of compartment syndrome?

Answer 13

• Pain
• Pulselessness
• Pallor
• Paralysis
• Paraesthesia
• Perishingly cold

Question 14

Why are the 6 Ps useless?

Answer 14

Compartment syndrome should be picked up before these signs occur

Question 15

How can diagnosis of ACS be made?

Answer 15

Diagnosis can be made clinically or on the basis of compartment pressure monitoring

Question 16

What are the two main criteria for diagnosis ACS from compartment pressure monitoring?

Answer 16

• Pressure >40mmHg
  OR
• Pressure differential 30mmHg below diastolic blood pressure – especially important in the hypotensive patient!

Question 17

What investigations can be made into ACS?

Answer 17

Intracompartmental pressure can be measured through using a wick catheter, needle manometry or side-ported needles. MRI scans can help in clinically ambiguous situations.

Question 18

What is the treatment for ACS?

Answer 18

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

Question 19

Give four complications of ACS

Answer 19

• Muscle necrosis
• Joint stiffness
• Nerve fibrosis
• Delayed fracture union

Question 20

What occurs in ACS muscle necrosis?

Answer 20

Muscle necrosis can lead to fibrosis and shortening, resulting in ischaemic contracture and weakness.

Question 21

Give compartments of lower limb and incisions needed

Answer 21

Lower limb – 4 compartments
-	Anterior
-	Lateral
-	Deep posterior
-	Superficial posterior 
Two incisions, medial and anterolateral.

Question 22

Give compartments of thigh and incisions needed

Answer 22

Thigh – 3 compartments
-	Anterior
-	Medial 
-	Posterior
Two incisions, lateral and posterior (+/- medial)

Question 23

Give compartments of foot and incisions needed

Answer 23

Foot – 4 compartments
-	Medial 
-	Central
-	Lateral
-	Interosseous 
Three incisions, anteromedial, medial dorsal and lateral dorsal

Question 24

Give compartments of forearm and incisions needed

Answer 24

Forearm – 3 compartments
-	Palmar/flexor
-	Dorsal/extensor
-	Radial 
Two incisions, long palmar, dorsal, +/- carpal tunnel decompression

Question 25

Give compartments of handand incisions needed

Answer 25

Hand – 10 compartments
-	4 dorsal interosseous
-	3 palmar interosseous
-	Add. Pollicis
-	Thenar
-	Hypothenar
Four incisions made

Question 26

What are the five aspects of post-operative management of ACS?

Answer 26

• Leave wounds open
• Use loose, absorbent dressings
• Elevate gently
• Maintain fluid balance and adequate analgesia
• Reinspection +/- debridement +/- delayed closure at 2-5 days

Question 27

What is the prognosis of ACS?

Answer 27

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.