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 Stab Injury in Zone 1 of the Neck with 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. 1

Rationale for CTA in Stable Patients with Soft Signs

• Diffuse emphysema is considered a "soft sign" of injury in penetrating neck trauma
• The American College of Radiology specifically recommends CTA of the neck and chest as the imaging study of choice for patients with soft signs such as subcutaneous emphysema 1
• CTA has high sensitivity (90-100%) and specificity (98.6-100%) for detecting vascular injuries 1
• CTA can simultaneously evaluate:
  • Vascular structures
  • Aerodigestive tract
  • Soft tissue injuries
  • Trajectory of the penetrating object

Management Algorithm Based on Clinical Presentation

1. Initial Assessment:

   • Determine if patient has "hard signs" or "soft signs" of injury
   • Hard signs: active hemorrhage, pulsatile/expanding hematoma, hemodynamic instability
   • Soft signs: diffuse emphysema, nonpulsatile hematoma, venous oozing, dysphagia

2. For Stable Patients with Soft Signs (as in this case):

   • Proceed with CTA of neck and chest 1
   • This approach can avoid unnecessary surgical exploration in up to 74% of cases 1

3. For Unstable Patients or Those with Hard Signs:

   • Immediate surgical exploration without preoperative imaging 1

Special Considerations for Zone 1 Injuries

Zone 1 injuries (base of neck between clavicles and cricoid) warrant particular attention because:

• They involve structures in both neck and chest
• Risk of injury to major vascular structures (subclavian vessels, common carotid arteries)
• Potential for pneumothorax (as noted in evidence 2)
• Difficult surgical access

The "no zone" approach suggested by some research 3 still recommends CTA for patients with soft signs, which aligns with the recommendation for this case.

Follow-up Based on CTA Findings

• If CTA shows vascular injury: Consider angiography or surgical exploration 1
• If CTA shows aerodigestive injury: Proceed with contrast esophagram 1
• If CTA is negative but clinical suspicion for esophageal injury remains: Additional testing with contrast esophagram is recommended 1, 4

Important Caveat

While CTA has excellent sensitivity for vascular injuries, it has limitations for detecting esophageal injuries. Research indicates that up to 19% of esophageal injuries may be missed by CTA alone 4. Therefore, if there is clinical suspicion for esophageal injury despite negative CTA, additional diagnostic tests should be performed.

The presence of deep surgical emphysema on CTA has a very high negative predictive value (99.5%) for digestive tract injury, meaning the absence of this finding virtually excludes significant aerodigestive injury 5.