Os Odontoideum: Review Article

Abolfazl Rahimizadeh* and Ava Rahimizadeh

Os Odontoideum: Review Article

Os odontoideum is defined as an ossicle with circumferential smooth
margins and no osseous continuity with the body of axis.

While the size of the ossicle is variable, it has a smooth
surface, therefore, the cause of this condition has been presumed
to be both congenital and traumatic.

The possible cause of this condition has been implicated
in its underlying etiology. However, patients with this condition
may be asymptomatic or may be symptomatic of a variety of
neurological deficits and vascular dysfunctions.

The treatment of both the asymptomatic and
symptomatic characteristics of this condition has
undergone changes over the past few decades.

The most challenging issue encountered is the management
of OO with irreducible atlantoaxial dislocation.

This outlines the objective of our discussion to examine
the aforementioned subject extensively and review
the appropriate potential strategies for the treatment of this condition.

Os odontoideum or separate odontoid is a well-known pathology that was described for
the first time in the 19th century. The word OO has a Latin origin derived from os (bone) and
odontoideum (tooth-like).

In 1980, Fielding et al1 classified OO into 2 anatomic types.
In the orthotopic type of the condition, os is in its normal position
and it maintains a normal relationship with the clivus, atlas and the axis,
thus, available for free movement with the anterior arch of the atlas.

Orthop Res Traumatol Open J. 2016; 2(1): 6-28. doi: 10.17140/ORTOJ-2-107