Which of the following clinical findings is indicative of compartment syndrome?

Definition:

Compartment syndrome (CS) is a condition in which the perfusion pressure falls below the tissue pressure in a closed anatomic space, with subsequent compromise of circulation and function of the tissues. Each muscle and muscle group is enclosed in a compartment bound by rigid walls of bone and fascia. The compartments of the lower extremity are prone to developing elevated compartment pressures. Exercise-induced CS is the result of elevated compartment pressure that leads to ischemia of the muscles or nerves.

Etiology:

In 45% of cases, CS is caused by tibial fractures. Other causes include long bone fractures, vascular injuries, bleeding in enclosed spaces, intramuscular injections, drug overdose, or a tight cast dressing.

Incidence:

Acute CS varies depending on the inciting event. In 1981, DeLee and Stiehl found that 6% of patients with open tibia fractures developed CS, whereas only 1.2% of patients with closed tibia fractures developed CS.

Age-Gender:

Young adult males are especially at risk due to their muscle bulk and noncompliant fascia.

Race:

There is no evidence of differences between the races.

Clinical Presentation:

On a physical evaluation, the evidence of trauma and gross deformity should alert the physician to the possible development of CS. Compartment pressures greater than 40 mm Hg or a differential of less than 30 mm Hg with the diastolic is indicative of possible CS.

Pathophysiology:

CS develops after elevated compartment pressure causes muscle and nerve ischemia. When fluid is introduced into the compartment, the tissue pressure increases and raises the venous pressure.

Signs and Symptoms:

Patients with CS often have pain, a sensation of tightness, and weakness of the muscles involved. Pain on passive stretch is the most sensitive sign. Loss of pulses, sensation, or motor function occurs late.

Treatment:

Surgical treatment consists of an emergent fasciotomy (compartment release) with subsequent orthopedic reduction or fracture stabilization and vascular repair, if needed. The goal of decompression is restoration of muscle perfusion within 6 hours. Although several surgical techniques have been described, the double incision fasciotomy of the lower leg is the most common approach. To minimize soft tissue injury, especially in the setting of fracture/CS, some surgeons prefer a single incision approach. Regardless of the approach used, adequate decompression of all compartments is paramount.

Conditions Associated with Compartment Syndrome

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Soft tissue injury only (without a fracture)

Soft tissue injury with a fracture of the forearm, calf, hand, or foot (fractures of the forearm or tibia cause 58% of compartment syndrome cases seen in the Emergency Department)

Supracondylar fracture of the elbow (Volkmann ischemia)

Crush injury to hand, thigh, or foot

Gluteal trauma

Prolonged tourniquet application (>2 hours) and reperfusion after other causes of ischemia

Nephrotic syndrome

Infusion of fluids into forearm (e.g., leaking intravenous [IV] site, dialysis tubing, or intraosseous vascular access canula)

Anticoagulated patient or patient with coagulopathy

Arterial or venous thrombosis

Bites (e.g., dog, shark, and snake) in susceptible areas

Electrical injury, especially those involving muscle

Burns, especially those involving muscle

Obtunded patient

Intensive use of muscles from severe exertion, seizures, eclampsia, tetany

Exercise-induced compartment syndrome

It is important to understand that compartment syndrome can be the result of many different types of insults. Although it is more common in the calf or the forearm, compartment syndrome can also occur in the hand, foot, thigh, or buttocks. Rarely, it can occur in the lumbar region. When trauma is involved, the rule to be followed is the greater the amount of soft tissue trauma, the greater the chance of compartment syndrome. For this reason, any high-velocity injury should be treated with caution because the energy dissipated through the soft tissue can cause extreme swelling. Injuries commonly associated with compartment syndrome include automobile accidents and pedestrian trauma, especially bumper injuries to the buttocks, calf, or forearm. Gluteal compartment syndrome, which is frequently associated with an automobile accident or falling from a height, is due to the direct trauma and the associated swelling of the muscle compartment. Compartment syndrome can occur in the thigh because of a severe crush injury.

Compartment syndrome is a common result of trauma significant enough to cause a fracture. Volkmann ischemia is compartment syndrome in the forearm occurring after supracondylar fractures that cause a large amount of swelling around the elbow. Calcaneal fractures can also cause compartment syndrome, although this is rare. While a patient with a coagulopathy or on anticoagulation can develop spontaneous bleeding into a muscle compartment, leading to increased pressure, such a patient is even more likely to develop compartment syndrome if trauma is associated.

Anatomic Location and Grading of Injury

Compartment syndrome usually occurs after injuries to peripheral arteries, especially the popliteal, superficial femoral, external iliac, hypogastric, and brachial arteries. These vessels provide the bulk of blood flow to their respective limbs, so relatively minor injuries to the vessel can cause devastating ischemia distally. Collateral arteries around the knee, hip, and elbow may be open, but are usually insufficient to perfuse the leg or arm.

Injuries to abdominal vessels can cause compartment syndromes in the abdomen and the legs. Massive bleeding from aortic, vena cava, or iliac injuries, and the massive transfusion required for resuscitation, can lead to ACS. Interruption of arterial inflow (or obstruction of venous outflow) and associated shock can cause compartment syndrome in the legs secondary to ischemia and reperfusion injury (or venous hypertension with venous injuries). Compartment syndrome in the legs and ACS can occur in the same patient.

Extensive abdominal visceral injuries can cause ACS. Liver injuries are especially prone to this complication because they bleed a lot and often require sponge packs. Multiple small bowel and mesentery injuries also lead to ACS because of blood loss and bowel edema. Any combination of solid and hollow organ injuries leading to damage control laparotomy increases the risk of ACS. Postoperative care should include provisions for measuring IAP.

Tables 1 through 3 show the visceral, abdominal vascular, and peripheral vascular injuries that may cause compartment syndromes. They also display the ICD-9 codes and Organ Injury Scores.35

Introduction and Background

Acute compartment syndrome is a limb-threatening condition in which increased pressure within closed tissue spaces compromises the nutrient blood flow to muscles and nerves such that necrosis will invariably occur if decompression is not performed.1–4 This is in contrast to chronic (or recurrent) compartment syndrome, in which the mechanism of injury is usually exertional, symptoms most often subside at rest, and the condition is managed conservatively initially and by elective surgery when warranted.5–8 Acute compartment syndrome was first described in 1881 by a German physician named Dr. Richard von Volkmann.9 He reported on many cases of clawhand resulting from elbow injuries in children, which initially became known as “Volkmann's contracture.”

A compartment is a functional unit usually containing muscles, nerves, veins, and arteries. Each compartment is surrounded by a thick fascia that lacks the ability to stretch. A limb can contain more than one compartment; the four leg compartments are depicted in Figure 22-1. Acute compartment syndrome is not limited to the extremities; for example, it has been reported in the orbit10 as well as in the abdominal cavity.11

When pressure increases inside a closed compartment, it compresses both arterioles and venules. The increased venous resistance results in increased venular pressure, and presumably increased capillary pressure.12 This may explain why one observes more serious injuries in acute compartment syndrome-induced ischemia compared to that produced by tourniquet-induced ischemia alone, a condition associated with decreased venular pressure.13

COMPARTMENT SYNDROME

Compartment syndrome is a feared complication of many pediatric injuries and fractures and may not only result in severe, permanent injury but may also be limb or life threatening. Early detection and prompt treatment are key to avoiding complications from compartment syndromes. Risk factors for development of a compartment syndrome include fractures of the tibia, forearm, and elbow; crush injuries; bleeding disorders such as hemophilia; ipsilateral forearm and elbow injuries; and open fractures. Compartment syndrome may arise from both extrinsic and intrinsic causes.10 Intrinsic causes include crush injury, reperfusion injury, fractures, and intraoperative positioning. Extrinsic causes include compression from a cast or bandages. Any injury may develop into a compartment syndrome, and compartment syndrome may occur after elective surgery as well. There have also been recent reports of compartment syndrome after closed treatment of femur fractures with a spica cast.11 Patients with altered mental status (such as from a closed head injury) require particularly close evaluation because many of the common signs and symptoms of compartment syndrome will be absent (see later).10

Physiologically, compartment syndrome occurs as a result of increased pressure within a muscular compartment of an extremity. Muscle groups in the extremities are contained within fibro-osseous compartments. When there is swelling within the compartment (for example, after an injury, from bleeding, or from reperfusion), the compartment may not be able to expand sufficiently to accommodate the increased volume of the structures residing within the compartment. Consequently, tissue pressure rises within the compartment. Ischemia results when the pressure within the compartment is greater than the opening pressure of the venules traversing through the compartment.10

The diagnosis of compartment syndrome is best made on a clinical basis. Its signs and symptoms result from increased tissue pressure and subsequent ischemia. The involved compartments are often swollen to the point at which they are hard and tense. Classically, the diagnosis of a compartment syndrome is made on the basis of the “five p's”: pain (particularly pain with passive stretch of muscles contained within the involved compartment), pallor, paresthesias, pulselessness, and paralysis.10 The earliest and most sensitive clinical finding is pain. Pain from a compartment syndrome is frequently described as severe, unremitting, out of proportion to the initial injury, and poorly controlled by normal levels of analgesics. Intense pain with passive stretch of the muscles in the affected compartment is also a sign of compartment syndrome. Paresthesias, pulselessness, pallor, and paralysis may also be present in compartment syndrome; however, these symptoms usually occur late in the evolution of a compartment syndrome and frequently represent irreversible muscle and nerve ischemia.10

Neurologically impaired or very young patients may not exhibit the symptoms of a compartment syndrome or may be difficult to examine. In these situations or when the findings on examination are equivocal, the pressure within a compartment can be directly measured by one of several techniques. Compartment pressures greater than 30 mm Hg or within 20 mm Hg of diastolic blood pressure are considered suggestive of compartment syndrome.10

Treatment of compartment syndrome is surgical: a fasciotomy of the affected compartments should be performed to allow muscle swelling and decrease tissue pressure within the compartment. The fasciotomies are left open until the swelling subsides, at which point they are surgically closed. A high index of suspicion, early diagnosis, and prompt treatment are key to successful treatment of this often devastating condition.10

Chronic Compartment Syndrome

Chronic compartment syndrome involves an increase in compartment pressure through muscle hypertrophy, increased fluids, and compromised drainage of the area. Unlike the acute version, chronic compartment syndrome is mostly caused by exercise and strenuous activity. Common complaints from people with chronic compartment syndrome include a feeling of tightness and swelling in the leg, numbness, limited movement in the foot, and pain. In most cases, symptoms disappear shortly after activity is stopped. This form of compartment syndrome is most commonly addressed with changes in the exercise program, footwear, or orthopedic inserts.

Synopsis

Acute compartment syndrome is a surgical emergency with diverse etiologies. Acute compartment syndrome is classically described clinically with “the 6 P's”: pain, pallor, paresthesia, paresis, poikilothermia, and pulselessness. Clinical examination along with judgment is the gold standard for diagnosis; however, suspicion of compartment syndrome can be confirmed by measurement of intracompartmental pressures. The definitive treatment of acute compartment syndrome is early fasciotomy. Delayed or inadequate treatment can lead to poor outcomes, including limb amputation, poor motor and sensory nerve function, debilitating contractures, or even multi-organ failure and death. In this chapter, the pathophysiology, etiologies, diagnosis, and treatment of upper-extremity compartment syndrome are reviewed.

Compartment Syndromes

Compartment syndromes do occur in children and are related to the severity of the trauma (see Chapter 6). The lower part of the leg and the forearm are the most common sites for compartment syndromes and are usually the result of tibial shaft and supracondylar fractures of the distal portion of the humerus. The presence of a displaced supracondylar fracture and a displaced ipsilateral forearm fracture increases the risk of compartment syndrome. Compartment syndromes can also occur in other areas, such as the foot. The presence of open fractures does not preclude a compartment syndrome. Assuming that an open fracture has decompressed the adjacent compartments is a mistake inasmuch as a compartment syndrome develops in approximately 3% of open tibial fractures. Careful evaluation of injured extremities should therefore include assessment for signs of compartment syndrome. The most important findings include swelling and tenseness of the compartment and exaggerated pain with passive stretching of the distal joints. Paresthesias, pulselessness, and paralysis are late findings, and the absence of these signs does not rule out this diagnosis. Compartment pressures should be measured in all children with signs consistent with compartment syndrome. Uncooperative children or those with head injuries need to be evaluated very carefully because they will lack the usual symptoms. Rapid surgical treatment with the release of all involved compartments is critical in reducing potential complications.77 In the forearm, separate incisions are used to decompress the volar or extensor compartment (Fig. 5-5). The Henry approach, which entails division of the lacertus fibrosus, allows excellent exposure and decompression. In the lower part of the leg, the double-incision technique is recommended to decompress the four compartments (Fig. 5-6).