Abstract

Compartment syndrome is a condition in which increased pressure within one of the body's compartments results in insufficient blood supply to tissue within that space. There are two main types: acute and chronic. The leg or arm are most commonly involved.

Symptoms of acute compartment syndrome may include severe pain, poor pulses, decreased ability to move, numbness, or a pale color of the affected limb. It is most commonly due to physical trauma such as a bone fracture or crush injury. It can also occur after blood flow returns following a period of poor blood flow. Diagnosis is generally based upon a person's symptoms. Treatment is by surgery to open the compartment performed in a timely manner. If not treated within six hours, permanent muscle or nerve damage can result.

In chronic compartment syndrome there is generally pain with exercise. Other symptoms may include numbness. Symptoms typically resolve with rest. Common activities that trigger it include running and biking. It does not generally result in permanent damage. Other conditions that may present similarly include stress fractures and tendinitis. Treatment may include physical therapy or if that is not effective surgery.

Acute compartment syndrome occurs in about 3% of those who have a midshaft fracture of the forearm. Rates in other areas and for chronic cases is unknown. The condition more often occurs in those under the age of 35 and in males. Compartment syndrome was first described in 1881 by Richard von Volkmann. Untreated, acute compartment syndrome can result in Volkmann's contracture.

Signs and symptoms | Acute

The first symptom of compartment syndrome is pain. Loss of function and decreased pulses or pulselessness, however, are late signs. According to Shears, paresthesia in the distribution of the nerves transversing the affected compartment has also been described as relatively early sign of compartment syndrome, and later is followed by anesthesia (Shears, 2006).

- Pain is often reported early and almost universally. The description is usually of deep, constant, and poorly localized pain out of proportion with the findings on physical examination (often incorrectly described as pain out of proportion to the injury). The pain is aggravated by passively stretching the muscle group within the compartment or actively flexing it (though this finding is not specific to compartment syndrome alone) and is not relieved by analgesia up to and including morphine.

- Paresthesia (altered sensation e.g., "pins & needles") in the cutaneous nerves of the affected compartment is another typical sign.

- Paralysis of the limb is usually a late finding. The compartment may also feel very tense and firm (pressure). Some find that their feet and even legs fall asleep. This is because compartment syndrome prevents adequate blood flow to the rest of the leg.

- A lack of pulse rarely occurs in patients, as pressures that cause compartment syndrome are often well below arterial pressures and pulse is only affected if the relevant artery is contained within the affected compartment.

- Tense and swollen shiny skin, sometimes with obvious bruising of the skin.

- Congestion of the digits with prolonged capillary refill time.

Signs and symptoms | Chronic

The symptoms of chronic exertional compartment syndrome (CECS) are brought on by exercise and consist of a sensation of extreme tightness in the affected muscles followed by a painful burning sensation if exercise is continued. After exercise is ceased, the pressure in the compartment will decrease within a few minutes, relieving painful symptoms. Symptoms will occur at a certain threshold of exercise which varies from person to person but is rather consistent for a given individual and can range anywhere from 30 seconds of running to about 10–15 minutes of running. CECS most commonly occurs in the lower leg, with the anterior compartment being the most frequently affected compartment. Foot drop is a common symptom of CECS.

Causes | Acute

Because the fascia layer that defines the compartment does not stretch, a small amount of bleeding into the compartment, or swelling of the muscles within the compartment, can cause the pressure to rise greatly. Common causes of compartment syndrome include tibial or forearm fractures, ischemic reperfusion following injury, hemorrhage, vascular puncture, intravenous drug injection, casts, prolonged limb compression, crush injuries and eschars from burns. Less common causes include labor and delivery following uncomplicated births and C-sections.

Compartment syndrome can also occur following surgery in the Lloyd-Davies lithotomy position, where the patient's legs are elevated for prolonged periods. As of February 2001, any surgery that is expected to take longer than six hours to complete must include compartment syndrome on its list of post-operative complications. The Lloyd Davis lithotomy position can cause extra pressure on the calves and on the intermittent pneumatic compression device worn by the patient.

Causes | Chronic

When compartment syndrome is caused by repetitive use of the muscles, it is known as chronic compartment syndrome (CCS). This is usually not an emergency, but the loss of circulation can cause temporary or permanent damage to nearby nerves and muscles.

Complementary to chronic compartment syndrome is another subset known as chronic exertional compartment syndrome CECS, often called exercise induced compartment syndrome EICS. CECS of the leg is a condition caused by exercise which results in increased tissue pressure within a limited fibro-osseous compartment – muscle size may increase by up to 20% during exercise (Touliopolous, 1999). When this happens, pressure builds up in the tissues and muscles causing tissue ischemia (Touliopolous, 1999). An increase in muscle weight will reduce the compartment volume of the surrounding fascial borders and result in an increase of intracompartmental pressure. An increase in the pressure of the tissue can cause fluid to exude into the small spaces between the tissue known as interstitial space, leading to a disruption of the micro-circulation of the leg. This condition occurs commonly in the lower leg and various other locations within the body, such as the foot or forearm. This is commonly seen in athletes who train rigorously in activities that involve constant repetitive actions or motions. In athletic popular culture there is a catchphrase, "Feel the burn," which references these conditions as something to strive for when training, weightlifting or otherwise working out. They are not understood as symptoms. The symptoms involve numbness or a tingling sensation in the area most affected. Other signs and symptoms include pain described as aching, tightening, cramping, sharp, or stabbing. This pain can occur for months, and in some cases over a period of years, and may be relieved by rest. It also includes moderate weakness that can be a noticeable factor in the affected region. Chronic exertional compartment syndrome most commonly affects the anterior compartment of the leg, this can lead to problems with dorsiflexion of the ankle and the toes. The symptoms of CECS are often confused with more common injuries like shin splints and spinal stenosis. Treatment for chronic exertional compartment syndrome includes decreasing or subsiding exercising and activities, or cross training for athletes. In cases with severe intracompartmental pressures surgical treatment, a fasciotomy, is necessary.

Pathophysiology

During compartment syndrome there is increased intra-compartmental pressure in the interstitium over its capillary perfusion pressure, due to the accumulation of necrotic debris and hemorrhage, especially hemorrhage secondary to fractures (Rorabeck, 1984). Any condition that results in an increase in compartment contents or reduction in a compartment’s volume can lead to the development of an acute compartment syndrome. When pressure is elevated, capillary blood flow is compromised. Edema of the soft tissue within the compartment further raises the intra-compartment pressure, which compromises venous and lymphatic drainage of the injured area. Pressure, if further increased in a reinforcing vicious circle, can compromise arteriole perfusion, leading to further tissue ischemia. Untreated compartment syndrome-mediated ischemia of the muscles and nerves leads to eventual irreversible damage and death of the tissues within the compartment.

There are three main mechanisms that are hypothesized to cause compartment syndrome. One idea is the increase in arterial pressure (due to increased blood flow due to trauma or excessive exercise) causes the arteries to spasm and this causes the pressures in the muscle to increase even further. Second, obstruction of the microcirculatory system is hypothesized. Finally, there is the idea of arterial or venous collapse due to transmural pressure.

Acute compartment syndrome (ACS) of the lower extremity is a clinical condition that is seen fairly regularly in modern practice (Shagdan, 2010). Although pathophysiology of the disorder is well known to physicians who care for patients with musculoskeletal injuries, the diagnosis is often difficult to make (Shagdan, 2010). If left untreated, acute compartment syndrome can lead to more severe conditions including rhabdomyolysis and kidney failure potentially leading to death.

Diagnosis

Compartment syndrome is a clinical diagnosis made by a physician. It can be tested for by gauging the pressure within the muscle compartments. If the pressure is sufficiently high, a fasciotomy will be required to relieve the pressure. Various recommendations of the intracompartmental pressure are used with some sources quoting >30 mmHg as an indication for fasciotomy while others suggest a <30 mmHg difference between intracompartmental pressure and diastolic blood pressure. This latter measure may be more sensible in the light of recent advances in permissive hypotension, which allow patients to be kept hypotensive in resuscitation. It is now relatively easy to measure compartment and subcutaneous pressures using the pressure transducer modules (with a simple intravenous catheter and needle) that are attached to most modern anaesthetic machines.

Most commonly compartment syndrome is diagnosed through a diagnosis of its underlying cause and not the condition itself. According to Blackman one of the tools to diagnose compartment syndrome is X-ray to show a tibia/fibula fracture, which when combined with numbness of the extremities is enough to confirm the presence of compartment syndrome.

Treatment | Acute

Acute compartment syndrome is a medical emergency requiring immediate surgical treatment, known as a fasciotomy, to allow the pressure to return to normal. Although only one compartment is affected, fasciotomy is done to release all compartments. For instance, if only the deep posterior compartment of a leg is affected, the treatment would be fasciotomy (with medial and lateral incisions) to release all compartments of the leg in question, namely the anterior, lateral, superficial posterior and deep posterior.

An acute compartment syndrome has some distinct features such as swelling of the compartment due to inflammation and venous occlusion. Decompression of the nerve traversing the compartment might alleviate the symptoms (Rorabeck, 1984). Until definitive fasciotomy can be performed, the extremity should be placed at the level of the heart. Hypotension should also be avoided, as this decreases perfusion pressure to the compartment. Supplemental oxygen also optimizes tissue and neural oxygenation.

Treatment | Chronic

Chronic compartment syndrome in the lower leg can be treated conservatively or surgically. Conservative treatment includes rest, anti-inflammatories, and manual decompression. Elevation of the affected limb in patients with compartment syndrome is contraindicated, as this leads to decreased vascular perfusion of the affected region. Ideally, the affected limb should be positioned at the level of the heart. The use of devices that apply external pressure to the area, such as splints, casts, and tight wound dressings, should be avoided. If symptoms persist after conservative treatment or if an individual does not wish to cease engaging in the physical activities which bring on symptoms, compartment syndrome can be treated by a surgery known as a fasciotomy. Surgery is the most effective treatment for compartment syndrome. Incisions are made in the affected muscle compartments so that they will decompress. This decompression will relieve the pressure on the venules and lymphatic vessels, and will increase bloodflow throughout the muscle. Left untreated, chronic compartment syndrome can develop into the acute syndrome and lead to permanent muscle and nerve damage.

A military study conducted in 2012 found that teaching individuals with lower leg chronic exertional compartment syndrome to change their running stride to a forefoot running technique abated symptoms. Follow up studies are needed to confirm the finding of this study.

Hyperbaric oxygen therapy has been suggested by case reports – though as of 2011 not proven in controlled randomized trials – to be an effective adjunctive therapy for crush injury, compartment syndrome, and other acute traumatic ischemias, by improving wound healing and reducing the need for repetitive surgery.

Complications

Failure to relieve the pressure can result in necrosis of tissue in that compartment, since capillary perfusion will fall leading to increasing oxygen deprivation of those tissues. This can cause Volkmann's contracture in affected limbs. As intercompartmental pressure rises during compartment syndrome, perfusion within the compartment is reduced leading to ischemia, which if left untreated, results in necrosis of nerves and muscles of the compartment (Shears, 2006). Rhabdomyolysis and subsequent renal failure are also possible complications.

Notable cases

PBS science correspondent Miles O'Brien suffered a compartment syndrome and had to have his left arm amputated. According to his blog, O'Brien was securing cases filled with camera gear on a cart as he wrapped up a reporting trip to Japan and the Philippines. One fell on his arm. The arm was sore and swollen the next day but worsened on the next, Feb. 14, 2014, and he sought medical care. At the hospital, as his pain increased and arm numbness set in, a doctor recommended an emergency procedure to relieve the pressure within the limb, O'Brien wrote. The doctor made a real-time call and amputated his arm just above the elbow.

NFL Player Rahim Moore suffered a compartment syndrome in his left calf in November 2013, but doctors treated it soon enough that they were able to save his leg.

Kara Goucher, professional long distance runner and Olympian, had chronic exertional compartment syndrome and subsequent fasciotomies. She describes her experience: "Having compartment surgery changed my life. I was always in so much pain and unable to do the proper training that I needed. I had compartment surgery twice. I had it on both legs in 1999 on my lateral and anterior compartments and again in 2005 on my right posterior calf. Both times it was a huge success for me. As soon as the stitches came out and the wound healed, I was able to run pain free for the first time in years."