Atlas C1

Background 

• High energy axial load – Jefferson facture 
• Low enegy eledely 
• 50% associated spine 
• 40% assocaited Axis 
• Neuro injury low (capacious canal) 

Classification 

• Landell 
  • Type 1 – isolated posterior or anterior arch 
  • Type 2 – bilateral A and P arch (Jefferson burst) 
  • Type 3 – unilateral lateral mass 
• TL Classification 
  • Intrasubstance 
  • Avulsion 

Radiographs 

• ADI 
  • ❤ normal 
  • 3-5 TL damaged, alar and apical intact 
  • >5 everything damaged 
• Lateral ADI 
  • Asymmetry >2mm  
• Lateral Mass overhand 
  • Combined should be <7mm 

Management 

• Depends on TL* key predictor of stability 
  • Intact – Halo or collar 3 mo 
  • Disrupted – C1-2 fusion 

Complication 

• Cock Robin 
  • Sagittal split 
  • OC settles onto C2 SAP 

TL injured if 

• ADI ❤ 
• LM displacement >8.1