Acute compartment syndrome refers to acute ischemia of the muscles and nerves within a compartment due to elevated intra-compartmental pressure. This should be differentiated from exertional compartment syndrome which occurs in the compartments of the leg, typically the anterior and lateral, during exercise and resolves with rest. Acute compartment syndrome can occur from swelling or bleeding within the compartment or from external compression. Etiologies include fracture, crushing injury, vascular injury, intravenous extravasation, burns, and compression from cast/dressings. Compartment syndrome has been described in many locations including the leg, forearm, foot, deltoid, arm, hand, gluteal compartments, and thigh. Compartment syndrome can occur in open fractures. Compartment syndrome is common in tibial shaft fractures and can occur after open reduction internal fixation if fasciotomies are not performed.
It is often difficult to obtain an accurate physical exam in patients with acute compartment syndrome due to intoxication, delirium, sedation, narcotic administration, and multiple severe distracting injuries. The most common complaint is pain in the compartment of concern. The pain is worse with movement of the muscles, especially passive stretch. Other complaints include loss of sensation, weakness or paralysis, and a cool distal extremity.
The signs and symptoms of compartment syndrome include the following:
- Firmness of compartment
- Pain (out of proportion to what one would expect, especially with passive stretch of the muscles)
- Pallor (pale color)
- Poikilothermia (cold distal extremity compared to the contralateral side)
Intracompartmental pressure can be measured with a Stryker needle. Fasciotomy has been recommended for compartment pressures greater than 30 mmHg, pressures within 30 mmHg of the diastolic blood pressure, and pressures within 30 mmHg of the mean arterial pressure (MAP). However, most rely on a clinical diagnosis rather than intracompartmental pressures if the patient is able to cooperate.
Treatment for acute compartment syndrome is surgical release of the involved compartment(s). Wherever the location, one or more generous skin incisions should be made and all constricting tissues should be released. Small skin incisions with subcutaneous fasciotomies are not appropriate for acute compartment syndrome.
The most commonly performed fasciotomy is that of the leg. All four compartments of the leg can be released with either a two-incision (medial and lateral) or a one-incision (lateral) fasciotomy. In the one-incision fasciotomy, the anterior and lateral compartments are released directly. The superficial posterior compartment is released by elevating the skin posteriorly. The deep posterior compartment is released by dissecting posterior and medial to the fibula.
Complications of compartment syndrome are common, especially if the diagnosis is missed or delayed. Patients may have irreversible nerve and muscle damage. Damaged muscle may result in fibrosis and contracture. With large amounts of muscle involvement rhabdomyolysis, renal failure, and shock can occur. Fasciotomies can also result in complications such as nerve injury, infection, wound healing issues, and the need for flap coverage.
Red Flags and Controversies
There is some controversy surrounding the pressure criteria for surgical intervention of compartment syndrome. Fasciotomy has been recommended for pressures greater than 30 mmHg, for pressures within 30 mmHg of the patient's diastolic blood pressure, and for pressures within 30 mmHg of the patient's mean arterial pressure (MAP). It has been suggested that the use of 30 mmHg as a fixed, absolute definition of compartment syndrome is less accurate. Most orthopaedic surgeons regard acute compartment syndrome as a clinical diagnosis and perform fasciotomies when clinically appropriate. Compartment pressures are relied upon when the patient is unable to respond appropriately to the clinical exam (intubated, obtunded, etc.).
The outcome of compartment syndrome is dependent on location, severity, time between onset and treatment, and associated injuries. There is little published on the outcomes of fasciotomies. In one review of 40 cases of lower extremity fasciotomy the only predictor of a poor outcome was patient age over 50 years (Heemskerk, World J Surg, 2003). In the same study, 45% had good limb function, 28% had salvaged limbs with diminished function, 12% had amputation, and 15% died.