Subaxial Facet Dislocations

Posted bythespinebookadminPosted inTopics, Trauma

Background 

  • Spectrum of illness 
  • Bimodal 
  • 20% at C7-T1 junction 
  • Mechanism 
    • Flexion distraction 
    • Flexion distraction rotation 

Progression of Injury 

  • Facet subluxation 
  • Unilateral dislocation 
    • 25% displacement anterolisthesis (this is a cool trick to tell on XR what it is) 
    • Radiculopathy 
    • Disc herniation 56% 
  • 50% displacement 
  • SCI 
  • Disc herniation 82% 
  • Complete dislocation 
    • 100% displacement 
    • SCI 

Disc Herniation Significance 

  • On reduction, the disc herniation can cause SCI / compression 
  • Disc material posterior to body most concerning 

Imaging 

  • XR 
  • CT scan 
    • Hamburger bun sign normal 
    • Reverse hamburger bun sign is facet dislocation 
    • Naked facet sign is facet dislocation 

MRI Decision 

  • Obtain MRI 
    • Neuro intact patient 
      • No urgency for reduction 
      • Risk of converting intact to SCI 
    • Obtunded 
      • May be neuro intact 
    • Planning posterior approach and reduction 
  • Omit MRI 
    • Incomplete SCI or worsening 
      • Would benefit from urgent reduction 
    • Complete cord 

Management 

  • Closed Reduction 
    • Contraindication 
      • Disc Herniation 
      • Proximal C spine injury 
  • Anterior 
    • Indications 
      • Disc herniation 
      • preference 
    • Adv 
      • Removes disc 
      • Single motion segment fusion 
    • Disadv 
      • More difficult reduction 
      • Failure to reduce requires posterior reduction and fixation then return to front for fix 
    • Reduction 
      • Caspar (distract and derotate) 
      • Lamina spread 
      • Cobb 
  • Posterior 
    • Indications 
      • No disc herniation 
    • Reduction 
      • Towel clips 
      • Lever the facets with Penfield 4 
      • Resect tip of SAP of lower vertebra if it blocks you