Compartment Syndrome

Contents

• Introduction
• Definition
• Etiology
• Pathogenesis of Compartment Syndrome
• Physical Exam
• Investigation
• Treatment
• Complications

Introduction

Compartment Syndrome is most common in the lower leg (commonly associated with tibial fractures) in adults and upper limb in children.

Definition

• increased interstitial pressure in an anatomical “compartment” (forearm, calf) where muscles and tissue are bounded by fascia and bone (closed osteofascial compartment) with little room for expansion resulting in vascular compression.
• If the interstitial pressure exceeds capillary perfusion pressure for several hours (4 to 6 hours), muscle necrosis and eventually nerve necrosis may result.

Etiology

• intracompartmental: fracture (particularly tibial fractures, pediatric supracondylar fractures, and forearm fractures), crush injury, revascularization
• extracompartmental: constrictive dressing (circumferential cast), circumferential burns

PEARL chronic (exertional) compartment syndrome can develop in individuals involved in a major change in activity level (long-distance runners, military recruits, etc.); compartmental pressure slowly falls to normal following cessation of exercise.

Pathogenesis of Compartment Syndrome

The 6 P’s of Compartment Syndrome

1. Pain
   -out of proportion to the injury
   -not relieved by analgesia
   -increased with passive stretch of compartment muscles (most specific)
2. Pallor
3. Paresthesia
4. Polar:
   -cold limb (late finding)
5. Paralysis (late finding)
6. Pulselessness (late finding)

Physical Exam

• Pain out of proportion to the injury. Increase pain with passive stretch is the most sensitive clinical exam finding for compartment syndrome.
• 6 Ps
• Compartment pressures (Stryker)
  • Test is positive if pressures are above 30mmHg or within 30mm of diastolic blood pressure
  • All compartments must be measured
• Be aware that sedated patients or those with regional anesthesia will not have “pain out of proportion”.
• Hypotension potentiates compartment syndrome

Investigation

• usually not necessary as compartment syndrome is a clinical diagnosis
• in children or unconscious patients where clinical exam is unreliable, compartment pressure monitoring with catheter, AFTER clinical diagnosis is made (normal = 0
  mmHg; urgent = 30 mmHg or within 30 mmHg of diastolic BP)

Treatment

1. Divide all dressings down to skin from top to bottom. Remove all constrictive dressings (casts, splints)
2. Elevate the limb.
3. Reassess in 20 minutes
4. Consider measurement of compartment pressures. BUT the diagnosis is primarily clinical and if a compartment syndrome is suspected definitive treatment is SURGERY.
5. SURGERY – 4 compartment fasciotomy, surgical division of the fascia surrounding the four compartments of the lower leg in the operating room.

Complications

• rhabdomyolysis, renal failure secondary to myoglobinuria, Volkmann’s ischemic contracture

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