Odontoid C2  

Posted bythespinebookadminPosted inTopics, Trauma

Background 

  • Bimodal 
    • Low energy elderly – increase morbidity vs younger, often missed 
    • High energy young 
    • Children – basical synchondrosis, rare 
  • C2 is the axis 
  • Odontoid fracture most common fracture of axis 
  • Pathophys 
    • Anterior displacement – TL failure and AA instabiltiy 
    • Posterior displacement – dirrect impactt from anterior arch during hyperextension 
  • Od odontodieum 
    • Looks like type 2 odontoid 
    • Failure of fusion vs residual old traumatic process 
  • Osteology 
    • 5 ossificaiton centers 
      • Body 
      • Dens 
      • Tip – appears age 3, fuses age 12 
      • 2 arches 
    • Dens – body junction (subdental basical synchondrosis) 
      • Fuses age 6 
      • Vascular watershed 
        • Vertebral A branches 
        • Internal carotic branches 

66.  Regarding the synchrondroses of C2 odontoid, which is true: 

provides to longitudinal growth of C2 

in the plane of the fracture 

fuses at age 10 

Regarding the synchrondroses of C2 odontoid, which is true 

a. It contributes to longitudinal growth of C2 

b. It is in a different axis than odontoid fractures 

c. Fractures through it can lead to C1-2 instability 

d. It fuses at adulthood 

Classification – Anderson and D’Alonzo with Grauer for Type 2 

  • Type 1 – tip (alar ligament) 
    • R/o associated AO instability with flex ex films 
  • Type 2 – basilar waist (36% non union) 
    • A – Transverse 
    • B – obliquity  
    • C – reverse obliquity 
  • Type 3 – body 

RF for Non Union 

  • 5mm posterior displacement 
  • Angulation >10 
  • Age >40 
  • Delay >4d 
  • Fracture gap >1mm 
  • Smoking 
  • Concomitant neurologic injury 

Management 

  • Type 1 and 3 – collar 
  • Type 2 
    • Young 
      • RF – OR 
      • No RF – Halo 
    • Elderly 
      • Collar (fibrous union acceptable) 
      • OR 

Imaging 

  • Lateral 
  • Odontoid open mouth 

Operative Choices 

  • C1-2 Fusion  
    • Harms 
    • Transarticular 
      • c/i: abberrant VA 
    • Gallie wiring 
  • Odontoid Screw 
    • Indications: 2B Oblique 
    • Contraindications: osteoporosis, comminution, irreducible, chronic, barrel chest, short neck 
    • Higher failure, lower union 

Complications 

  • Non union 
    • 33-88% 
    • 36% Type 2 
    • See above fo risk factors 
  • >80 high morbidity and mortality 

Anderson and D’Alonzo 

  • 1.) Tip of odontoid (alar avulsion) 
    • Very rare 
  • 2.) Waist fracture (high nonunion rate – 30%) 
    • Mechanically unstable region 
    • Risk factors 
      • 3mm displacement 
      • 10 degrees angulation 
      • Age >50 
      • Smoking 
      • Posterior displacement 
      • Delayed presentation 
  • 3.) Into cancellous body 
    • If it dips into body at ALL (into joint) – it is type 3 

Management 

  • Type 3 – collar (Halo for unreliable patients) 
  • Type 2 in elderly 
    • Controversial regarding ORIF vs immobilization 
      • Risk of backing out 
      • Risk of loosening 
      • Anterior approach risks (dysphagia) 
    • Optimal NON-Operative choice 
      • Hard cervical collar >>>> Halo 
  • Type 2 in young 
    • Anterior vs posterior 
    • Anterior ORIF – single lag screw (in amenable fractures) 
    • Posterioer – transarticular screw vs C1-C2 fusion