Flail Chest

General Considerations

• Segment of thoracic cage is separated from remainder of chest wall by significant blunt chest trauma
• Relatively uncommon, but potentially life-threatening
• Definition varies from two fractures per rib for two contiguous ribs to two fractures per rib for three contiguous ribs
• Sternum may also be involved with ribs on both sides of chest
• Severity of underlying lung and cardiac injury are clinically more important than fractures themselves

Clinical Findings

• Chest wall bruising
• Pain on inspiration
• Crepitus
• Flail segment moves paradoxically with respiration
  • Moves inward on inspiration and outward on expiration

Imaging Findings

• Chest radiographs are invariably performed first
  • Two or more fractures in two or three or more contiguous ribs
• Chest x-rays tend to underestimate the number of fractures
• Chest CT is also invariably performed, and may show
• Rib fractures
• Pulmonary contusion (almost always)
• Airspace disease representing hemorrhage into the alveoli usually subjacent to the point of impact
• Pulmonary laceration
• Lacerations in the lung may be blood-containing, air-containing, or both
• Frequently masked by the surrounding pulmonary contusion
• Pneumothorax (very common)
• Since the severity of the injury means a supine radiograph will be performed, pneumothoraces may only be seen on chest CT
• Hemothorax (common)
• Pneumomediastinum
• Subcutaneous emphysema
• Mediastinal hemorrhage
• Aortic injuries

Treatment

• Analgesia, including intercostal nerve blocks
• Ventilation and oxygenation
  • Patients who do not need mechanical ventilation do better than those who do

Complications

• Almost always accompanied by pulmonary contusion
• May have long-term disability
  • Chest wall pain
• Respiratory distress

Prognosis

• Up to 10% mortality if patients reach hospital alive

Flail Chest. Radiograph demonstrates multiple rib fractures (black arrows) with
some ribs fractured in two or more places. There is also a pulmonary contusion (red arrow) and subcutaneous emphysema (white arrow)
For this same photo without the arrows, click here
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eMedicine: Flail Chest. Bjerke, H