Table 4.

Proposed classification and treatment algorithm of Odontoid fractures by Grauer et al.8)

Subtype	Description	Treatment guideline
Type I	Above inferior aspect of C1 anterior arch	External immobilization*
Type II	Between types I and II fractures
Type IIA	Nondisplaced fracture	External immobilization
Type IIB	Anterior superior to posterior inferior and displaced transverse fractures	Anterior screw fixation
Type IIC	Anterior inferior to posterior superior or comminuted fractures	Posterior atlantoaxial fusion
Type III	Including at least one of the superior articular facets of C2	External immobilization

^*Halo-vest fixation or Philadelphia brace.