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|Classification and external resources|
|Classification and external resources|
Compartment syndrome is a limb- and life-threatening condition which occurs after an injury, when there is insufficient blood supply to muscles and nerves due to increased pressure within the compartment such as the arm, leg or any enclosed space within the body. If uncorrected, the lack of blood supply leads to injury in the affected muscles and nerves. The severity of compartment syndrome can be divided into acute, subacute, and chronic compartment syndrome.
Classically, there are 6 "Ps" associated with compartment syndrome — pain out of proportion to what is expected based on the physical exam findings, paresthesia, pallor, paralysis, pulselessness, and pressure. The first signs of compartment syndrome are numbness, tingling and paresthesia. 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). The other three symptoms of compartment syndrome are palpable pulse, paresis and pallor. These symptoms are irreversible and consistent during compartment syndrome and they are part of the diagnosis (Shears, 2006).
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 burns. Another possible cause can be the use of creatine monohydrate. 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[where?] 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. When compartment syndrome is caused by repetitive use of the muscles, as in a cyclist, 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. The cause of compartment syndrome is due to excess pressure on or within the muscle compartments. This pressure can occur for many different reasons, many are due to injuries. Injuries cause the swelling of tissue. The swelling of the tissue forces pressure upon the muscle compartments, which has a limited volume. Due to this pressure, the venules and lymphatic vessels that drain the muscle compartments are compressed, and are prevented from draining. As arterial inflow continues while outflow is decreased, the pressure builds up in the muscle compartments. This pressure will eventually decrease the amount of blood flow over the capillary bed, causing the tissue to become ischaemic. The tissues will release factors and will lead to the formation of edema.
Complementary to chronic compartment syndrome is another subset known as chronic exertional compartment syndrome CECS, often called exercise induced compartment syndrome EICS . According to Touliopolous, CECS of the leg is a condition caused by exercise which results in increase 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 in will reduce the compartment volume of the surrounding fascial borders and resulting 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. 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 are often relieved by rest. It also includes moderate weakness that can be a noticeable factor in the affected region. Chronic extertional 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 spiral stenosis. Treatment for chronic exertional compartment syndrome includes decreasing or subsiding exercising and activities, or cross training for athletes.
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 haemorrhage, especially haemorrhage 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.
Compartment syndrome is a clinical diagnosis. However, 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.
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 arterial occlusion. Decompression of the nerve traversing the compartment might alleviate the symptoms (Rorabeck, 1984).
Subacute compartment syndrome, while not quite as much of an emergency, usually requires urgent surgical treatment similar to acute compartment syndrome.
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. In cases where symptoms persist, the condition can be treated by a surgical procedure, subcutaneous fasciotomy or open fasciotomy. Left untreated, chronic compartment syndrome can develop into the acute syndrome. A possible complication of surgical intervention for chronic compartment syndrome can be chronic venous insufficiency.
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. The main treatment for compartment syndrome is surgical. 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.
Technology solutions for compartment syndrome involving continuous monitoring have also been proposed and tested.
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.
17 "Compartment Syndrome -OrthoInfo - AAOS." Compartment Syndrome -OrthoInfo - AAOS. N.p., n.d. Web. 07 Dec. 2013.
18. Paik, Ronald S., Douglas Pepples, and Mark R. Hutchinson. "Chronic exertional compartment syndrome." pain 78 (2007): 136-42.