Six P’s of Compartment Syndrome

A compartment syndrome occurs when injured tissue swells within the fascia and connective tissues inside of a limb causing an increase in the pressure within that “compartment”. Our muscles are split and divided by connective tissue. These, fibrous layers of connective tissue, known as fascia, surround our muscles and form a septum that divides the compartments.

Here is how it happens; the deep fascia that covers the muscles form an INTERMUSCULAR SEPTUM that penetrates and attaches to the bones.

In the case of the forearm, these septa will form an anterior or flexor compartment, and a posterior or extensor compartment. But besides their function it is important to understand that these compartments are in some way isolated from each other and they have their own neurovascular supply.

When damage occurs to the a muscle or muscle group within the fascial compartment, the resulting swelling and bleeding can create an increased pressure that, if left untreated, can choke off circulation, eventually leading to localized cellular hypoxia and death. The pressure within the closed fascia “compartment” becomes a tourniquet for the surrounding tissue  and distal structures supplied by the same neurovascular elements. When left unrecognized or untreated, compartment syndrome can lead to loss of limb function and even loss of the limb itself.

For our physical assessment, there are 6 P’s to consider. These six signs are often associated with compartment syndrome.

1] Pain

 

Pain is the universal symptom in compartment syndrome. While significant pain is almost always present as the pressure within the limb compartment rises, we may mistakenly attribute it solely to the injury itself. When pain seems dramatically out of proportion for the severity of the mechanism, consider the possibility of a compartment syndrome and look a little closer.

The pain typically felt with compartment syndrome is a dull, deep aching that is difficult to localize. Pain that increases upon manipulation of the muscle is also suspect for compartment syndrome.

2] Paresthesia

This is that hallmark “pins-and-needles” sensation that we feel when one of our limbs has been without adequate circulation for a period of time. If you’ve ever had a crossed leg become temporarily numb while you were sitting down and then felt a rush of pin-prick sensations as circulation returned, you’ve felt two different types of paresthesia (numbness and tingling).

Numbness isn’t typically associated with our run-of-the-mill limb injuries. It can indicate nerve damage or it might suggest a progressing compartment syndrome.

3] Pallor

Pale, shiny skin distal to the injury should raise our suspicion of compartment syndrome. Bruising may also be present.

4] Paralysis

More common in crush injuries, the total inability to move the limb distal to the injury might suggest compartment syndrome. If the limb is still intact, some movement should be possible in the distal extremity. If the limb is lifeless we should suspect significant muscle and nerve disruption and, possibly compartment syndrome.

5] Pulselessness

 

We normally associate pulelessness with the severely angulated limb or massive soft tissue damage. But the absence of a pulse distal to the extremity can be caused by any mechanism that produces a tourniquet type effect.

6] Poikilothermia

In the context of compartment syndrome it refers to the finding of differing temperatures between the affected limb and the uninjured limb. Place a hand on the painful limb just distal to the injury or the site of pain. Then place your other hand on the opposite limb in the same location. If the affected limb feels cooler than the unaffected limb, this suggests that the injured limb is unable to thermoregulate.

When treating limb injuries, compartment syndrome is definitely a possibility that you should add to your differential diagnosis bag. Acute compartment syndrome is a limb threatening issue that requires surgical intervention.  

A 15 year-old male sustained high energy injury to forearm. X-ray showed proximal comminuted ulnar fracture. Physical exam revealed severe painof the entire forearm and hand, pallor, paralysis, and lack of distal pulses. A Stryker intercompartmental device revealed increased compartment pressure.

 

Picture shows a fasciotomy [compartment release] of the flexor compartment that was indicated to release the pressure.

The definitive surgical therapy for compartment syndrome is emergent fasciotomy (compartment release), with subsequent fracture reduction or stabilization and vascular repair, if needed. The goal of decompression is restoration of muscle perfusion within 6 hours.