Compartment syndrome
Consequences of a compartment syndrome resulting in severe tissue loss

Definition

Compartment syndrome refers to the elevation of interstitial pressure within a closed compartment of the human body that results in microvascular compromise, tissue ischaemia and necrosis.

Anterior, medial, and posterior compartments of the thigh. The medial and lateral septa attached to the femur separate the anterior from the medial/posterior compartments.

Pathology

A compartment syndrome is the build-up of fluid within a body compartment, which may occur in any body region with the following clinical manifestations: head (increased intracranial pressure), chest (tension pneumothorax), heart (pericardial tamponade), abdomen (intraabdominal compartment), extremities (compartment syndromes). It is a critical condition that requires immediate medical attention and management. In the head, chest and abdomen it is life-threatening, in the extremities a limb-threatening condition.

In the upper and lower extremities, a compartment is a unit formed by a number of muscles, nerves and blood vessels that are held together by a rigid membrane of connective tissue called fascia. With tissue swelling (oedema) caused by an injury, a fracture or a surgical procedure the pressure within the tissues increasingly raises to exceed the venous pressure. This causes local accumulation of fluid containing toxic metabolic products that are not transported away through the venous system causing damage to the surrounding tissues.

A compartment syndrome leads to acute pain, impairment of venous and arterial blood transport and oxygenation, leading to tissue ischaemia, nerve alteration and finally death of the affected tissue. The pathology is often distinguished into an acute and chronic condition, such as Chronic Compartment Syndrome in athletes.

Acute compartment syndrome develops rapidly thus requiring immediate diagnosis and management. With delay to treatment it may lead to irreversible necrosis of muscle, skin and other tissues that need to be surgically excised, leaving the patient with debilitating consequences. Chronic compartment syndrome affects mostly the lower leg and is usually less severe, in most cases easily managed conservatively.

The complications arising from a compartment syndrome are chronic pain, muscle and nerve damage, infection after surgical fasciotomy, possibly leading to limb amputation. A Volkmann contracture is a permanent limb deformity of the forearm. It occurs when a compartment syndrome remains untreated resulting in a non-functional extremity due to ischaemic consequences affecting the forearm muscles. 

Classification

Fractures of the humerus shaft can display various patterns: transverse, oblique, spiral, and comminuted. In addition they are differentiated depending on whether the fracture is displaced or undisplaced, relative to the loss of bone alignment and closed or open fracture. The AO (Arbeitsgemeinschaft für Osteosynthesefragen) Foundation, an international organisation founded in Switzerland, focussing on research and education for the management of orthopaedic injuries), is one of most used systems available to characterise humerus shaft fractures. According to the AO humerus shaft fractures are divided into their level of comminution:

Type A - No comminution

Type B - Presence of butterfly fragment (wedge-shaped fragment of bone

Type C - Comminution

A bruise and tissue swelling caused by a fracture can lead to a compartment syndrome

Causes

A compartment syndrome may develop as a result of:

Bone fracture (75% of cases) especially of the tibia, humerus, radius + ulna

Vascular injury with or without fracture

Haemorrhage

Crush injury of extremities: muscle oedema

Burn: increased capillary permeability and tissue fluid entrapment

Constricting dressing, bandage, plaster, cast, tourniquet

Blunt trauma

Abdominal surgery

Arthroscopic surgery of the knee is a risk factor for a compartment syndrome

Risk factors

There is a vast number of risk factors potentially leading to a compartment syndrome either in isolation or combined:

Limb fractures (1-9 % incidence of compartment syndrome)

Trauma associated with vascular injuries

Haemorrhage

Burns

Open and arthroscopic surgery

Tight dressing (bandages, plaster, cast, tourniquet)

Deep vein thrombosis (DVT)

Anticoagulation therapy (haemophilia)

Athletes and soldiers performing exercise causing muscle microinjuries (also named chronic exertional compartment syndrome)

Cannulisation pumps for fluid or chemotherapy infusion

Use of injectable anabolic substances e.g. steroids

Drug and alcohol abuse

Severe swelling caused by a constricting cast

Symptoms

The symptoms of a compartment syndrome are divided into early, easily treatable signs and late symptoms that are often irreversible causing detrimental consequences such as limb amputation.

Initial signs

Disproportional pain relative to injury

Severe pain at rest

Prolonged substantial swelling

Increasing pain with muscle stretching

Tight tissues at touch

Tingling, burning sensation

Late signs

Absent pulse

Sudden cessation of pain

Appearance of skin demarcation

Loss of sensation (numbness)

Paralysis

Diagram of a device used to measure compartment pressure

Diagnosis

When a patient presents with traumatic injuries, swelling or a suspected fracture(s) the examining physician should always consider the possibility of an underlying compartment syndrome at the time or potentially developing in future. For a thorough evaluation, it is critical to remove bandages, plasters or any material covering the affected area.

Physical examination determines limb/tissue tightness, skin colour, presence of swelling, pulses, changes in sensation, level of pain at rest as well as with stretching and movement all of, which is compared to the healthy side (limb). Beside the clinical evaluation, a compartment syndrome is diagnosed with the measurement of compartment pressure with specific devices that should always be available in the Emergency Room.

Muscle pressure is normally up to 15 mmHg, increased between 25 – 30 mmHg and manifests as a compartment syndrome if over 45 mmHg. It is important to repeat all diagnostic parameters every 4 hours during the first day of admission because 4-8 hours post onset, the ischaemic changes become irreversible. Particular care should be given to patients with bleeding disorders and coagulopathy.

Laboratory tests include measurement of muscle proteins (creatine-phospho-kinase, CPK) in blood to detect life-threatening rhabdomyolysis and increase of muscle protein myoglobin in the urine (myoglobinuria), both factors indicative of muscle breakdown as a result of the increased interstitial pressure and ischaemia. Complete blood count is recommended to rule out infections or other pathologies (necrotising fasciitis). X-ray, CT or MRI scans are advised to detect fractures and soft tissue injuries.

Treatment

Patient treatment in a hyperbaric chamber

Non-operative

In the acute phase following the diagnosis when symptoms are not severe, conservative treatment of a compartment syndrome includes:

Removing any dressing, plaster, etc

Limb elevation to heart level

Ice pads

Analgesia

Frequent clinical monitoring of symptoms at 4 hour intervals

Repeated measurement of compartment pressure

Hyperbaric oxygen therapy to increase blood oxygenation and achieve hyperoxic vasoconstriction to attenuate tissue oedema.

Patient with severe compartment syndrome left with muscle tissue loss and functional limitations

Surgical treatment

If despite conservative treatment the compartment pressure increases to levels over 30 – 45 mmHg, the patient requires urgent surgery. Fasciotomy is the procedure of tissue decompression used to open the fascia surrounding the compartments and release the oedematous muscle, restore blood perfusion and prevent ischaemic damage. Then, if present, a fracture is reduced accordingly. The wound is normally kept open and a second look (procedure) is repeated multiple times as required. Vacuseals are often applied to temporally cover the wound and create a negative pressure to draw the excess interstitial fluid out of the affected tissue. The compartment is closed through stages and may require a skin graft to close the skin defect.

Partial weight bearing is recommended with early rehabilitation

Rehabilitation

The rehabilitation following a compartment syndrome is slow as the function of the affected limb may return if at all gradually. In case of lower extremity the patient will:

Avoid full weight bearing

Use crutches

At early stage: gentle exercises to restore flexibility and range of movement of all joints of the affected lower extremity

At later stage: vigorous exercises to increase muscle tone and strength

Occupational therapy is useful in case of debilitating decompressive surgery as it requires a longer rehabilitation.

Close monitoring of severely injured patients with compartment syndrome is pivotal to prevent serious complications

Prevention

Preventing a compartment syndrome requires a close monitoring of patients with any injury or surgery. A medical practitioner should always repeat frequently the diagnostics to detect the earliest symptoms of a compartment syndrome to allow for tempestive treatment and avoid detrimental complications.

In case of chronic compartment syndrome in cyclists, runners and other sports groups, it is recommended to perform regularly muscle stretch exercises, soft tissue massage, and biomechanical correction if necessary.