What is the next appropriate step in managing a stable patient with diffuse emphysema (air in the tissues) following a stab injury in zone 1 of the neck?

Management of Stable Patient with Zone 1 Neck Stab Injury and Diffuse Emphysema

For a stable patient with diffuse emphysema following a stab injury to zone 1 of the neck, CT angiography (CTA) of the neck and chest is the next appropriate step in management.

Rationale for CTA as First-Line Imaging

The American College of Radiology (ACR) Appropriateness Criteria for penetrating neck injury specifically recommends CTA as the imaging study of choice for patients with soft signs of injury 1. Subcutaneous emphysema is explicitly classified as a "soft sign" of vascular and aerodigestive injury that warrants imaging evaluation rather than immediate surgical exploration 1.

CTA offers several advantages in this clinical scenario:

• High sensitivity (90-100%) and specificity (98.6-100%) for detecting vascular injuries 2
• Simultaneous evaluation of extravascular soft-tissue and aerodigestive injuries with sensitivity of 100% and specificity of 93.5-97.5% 2
• Ability to evaluate the trajectory of the penetrating agent and identify associated injuries 1

Clinical Decision Algorithm

1. Initial Assessment:

   • Confirm hemodynamic stability
   • Verify intact airway (no respiratory distress)
   • Assess for hard signs of vascular or aerodigestive injury:
     • Active hemorrhage
     • Pulsatile/expanding hematoma
     • Bruit/thrill in wound region
     • Hemodynamic instability
     • Unilateral upper-extremity pulse deficit
     • Massive hemoptysis/hematemesis
     • Air bubbling in wound
     • Airway compromise

2. If patient remains stable with only soft signs (diffuse emphysema):

   • Proceed with CTA of neck and chest
   • Include chest imaging because zone 1 injuries can extend into the thorax and cause pneumothorax 3

3. Based on CTA findings:

   • Normal CTA: Continue observation
   • Vascular injury on CTA: Consider angiography or surgical exploration based on severity
   • Aerodigestive injury on CTA: Proceed with contrast esophagram (barium swallow) 1

Important Considerations

Why Not Immediate Surgical Exploration?

Immediate surgical exploration is indicated for patients with hard signs of injury or hemodynamic instability 2. For stable patients with only soft signs like emphysema, a "no zone" approach using CTA has been shown to reduce unnecessary negative explorations 4.

Why Not Observation Alone?

Simple observation without imaging would miss potentially life-threatening injuries. Zone 1 injuries are particularly concerning as they can involve vital structures including the great vessels, trachea, esophagus, and thoracic structures 1. The presence of diffuse emphysema strongly suggests an aerodigestive tract injury that requires evaluation 5.

Limitations of CTA

While CTA has excellent sensitivity for vascular injuries, it has limitations for aerodigestive injuries. A systematic review found that CTA missed 19% of esophageal injuries that were later diagnosed by swallow studies or surgical exploration 6. Therefore, if CTA is negative but clinical suspicion for esophageal injury remains high, additional diagnostic tests like contrast esophagram should be performed 1, 6.

Special Considerations for Zone 1 Injuries

Zone 1 injuries (from clavicles/sternal notch to cricoid cartilage) require particular attention because:

1. They can involve structures in both neck and thorax
2. They have potential for injury to major vessels (subclavian vessels, common carotid arteries)
3. They may cause delayed complications like pseudoaneurysms 7
4. They can result in bilateral pneumothoraces even from a unilateral wound 3

Conclusion

For a stable patient with diffuse emphysema following a stab injury to zone 1 of the neck, CTA of the neck and chest is the most appropriate next step. This approach allows comprehensive evaluation of potential vascular and aerodigestive injuries while avoiding unnecessary surgical exploration.