Compartment Syndrome

Roshan Melvani

Christopher M. Jones

INTRODUCTION

Acute compartment syndrome (ACS) is an increase in tissue pressure within an osseofascial compartment above tissue perfusion pressure, resulting in diminished local circulation and eventual tissue necrosis.
Operative intervention can decrease the degree of permanent muscle and nerve injury in the initial stages of compartment syndrome.
Volkmann ischemic contracture is a delayed finding of compartment syndrome and represents a continuum of static muscle contractures secondary to fibrosis and neurologic injury.
Pathoanatomy
- ACS results from a nonelastic constrictive element, such as muscle fascia, casts, or tight dressings, which decreases venous outflow and arterial inflow in the setting of bleeding or muscle swelling.
- Elevated intracompartmental pressure, when left untreated, results in a decrease in arterial perfusion to a level that is not compatible with tissue viability (Figure 51.1).
- Continued cellular anoxia leads to activation of apoptosis via upregulated lysosomal pathways.
- Permanent dysfunction of muscle occurs after 4 to 12 hours of anoxia.
Mechanism of injury
- External causes: extracompartmental compression by tight dressings or casts
- Internal causes: bleeding or swelling from fractures, penetrating injuries, blunt soft tissue trauma or crush injuries, ischemia-reperfusion injuries, deep burns, animal/insect bites, intravenous fluid extravasation, infection, and bleeding secondary to coagulopathy
Epidemiology
- The incidence of compartment syndrome in pediatric upper extremity fractures is as low as 1%. Pediatric fractures most associated with forearm compartment syndrome are both bone forearm fractures and floating elbow injuries.
- In adults, the most frequent upper extremity fractures correlated with compartment syndrome are both bone forearm fractures and distal radius fractures. Compartment syndrome is more commonly reported in males younger than 35 years, penetrating trauma, open fractures, and elbow dislocations.
- Compartment syndrome of the hand is most strongly associated with intravenous injections.

FIGURE 51.1 Pathoanatomy of compartment syndrome.

EVALUATION

Patient history
- A high index of suspicion must be present when there is pain out of proportion to injury.
- Increasing analgesic demands must be closely monitored and may be the most reliable symptom of evolving compartment syndrome in children.
- Loss of consciousness, altered mental status, diverting polytraumatic injuries, or regional anesthesia pose challenges in accurate diagnosis and may require objective tests such as compartment pressure measurements.
Physical examination
- Compartment syndrome is a clinical diagnosis that may in certain circumstances be confirmed based on objective findings.
- Consider the six P’s associated with ACS: pain, paresthesias, pallor, paralysis, pulselessness, and poikilothermia.
- Unrelenting pain is the earliest and most sensitive finding.
- Compartments will generally be tense on palpation, and passive stretch of the involved compartment will create intolerable discomfort.
- Compartment pressure can be measured if physical examination findings are ambiguous. The patient should be supine, with the affected extremity at heart level.
- An arterial line monitor or a handheld pressure-monitoring device (Stryker) may be used after appropriate calibration to avoid falsely elevated readings.
- Threshold pressures include 30 to 40 mm Hg or within 30 mm Hg of diastolic blood pressure. In patients with bleeding disorders, diffuse thrombocytopenia, or cellulitis, obtaining pressure measurements may pose additional risk. See Table 51.1.
Imaging
- Radiographs of affected portion of upper extremity should be obtained to evaluate for fracture, foreign bodies, subcutaneous air, or other pathologies that may be contributing to the disease process.
Classification
- ACS: tissue pressures increase within an osseofascial compartment, resulting in tissue ischemia.
- Exertional compartment syndrome: transient tissue ischemia secondary to nonelastic fascial compartment unable to acclimate to
  
  muscle amplification during increased activity. Patients report pain beginning as a slow ache within the first half-hour of beginning a specific activity until cessation and rest.
- Neonatal compartment syndrome: newborns may have upper extremity swelling with distinctive skin lesions known as “sentinel lesions of neonatal compartment syndrome.”

TABLE 51.1 Myofascial Compartments of the Upper Extremity and Their Contents

	Compartment	Muscle	Artery	Nerve
Arm	Anterior	Biceps, brachialis, coracobrachialis	Brachial	Musculocutaneous
	Posterior	Triceps	Profunda brachii	Radial
	Deltoid	Deltoid	–	Axillary
Forearm	Volar		Radial and ulnar	Median, ulnar, and anterior interosseous
	Superficial	Pronator teres, flexor carpi radialis, palmaris longus, flexor digitorum superficialis, flexor carpi ulnaris
	Deep	Flexor pollicis longus, flexor digitorum profundus, pronator quadratus
	Dorsal		Posterior interosseous	Posterior interosseous
	Superficial	Extensor digitorum communis, extensor digiti minimi, extensor carpi ulnaris
	Deep	Abductor pollicis longus, extensor pollicis brevis, extensor pollicis longus, extensor indicis proprius, supinator
	Mobile wad	Brachioradialis, extensor carpi radialis longus, extensor carpi radialis brevis	–	Radial
Hand	Thenar	Abductor pollicis brevis, opponens pollicis, flexor pollicis brevis	Digital	Recurrent motor
	Hypothenar	Abductor digiti minimi, opponens digiti minimi, flexor digiti minimi	–	Ulnar
	Adductor	Adductor pollicis	–	Ulnar
	Interosseous	Four dorsal and three palmar interosseous muscles	–	Ulnar
	Carpal tunnel	Flexor digitorum profundus, flexor digitorum superficialis, flexor pollicis longus	–	Median
	Digit		Digital	Digital
Reprinted from Chung KC. Operative Techniques: Hand and Wrist Surgery. 2nd ed. Philadelphia, PA: Elsevier Saunders; 2013:615-616, with permission from Elsevier.