Factors associated with nonunion in conservatively-treated type-II fractures of the
odontoid process. J Bone Joint Surg Br.
Aplasia of the
odontoid process. J Bone Joint Surg 1968;50A:833-4.
Reconstructed CT images showed osteolysis of the
odontoid process (Figure 2(d)).
Pathophysiologically, noninflammatory ROP consists of fibrocartilaginous tissue between the
odontoid process and the anterior arch of the C1 or between the dens and the transversal ligament [2, 16].
Odontoid Open Mouth View is for suspected C2 fracture and should show lateral masses of the first cervical vertebra and entire
odontoid process.7,13,14
Previously published studies find 9-18% of cervical fractures to be C2 fractures, of which 35-78% are
odontoid process fractures and 11-25% are traumatic C2 spondylolysis, Hangman's fractures [2-6].
It is likely that the odontoid fracture was not reduced well with this surgery technique, as a five-millimeter dorsal migration of the
odontoid process three weeks after the operation (Figure 1(b)) led to halo fixator installation, which had to be refixed once, for 16 weeks.
If the
odontoid process is involved as the bone erodes, posterior AAS possibly appears.
Despite such complexity, the
odontoid process and the body of C2 vertebra usually appear as a connected region collectively, having a total height that averaged 30 mm in adults, about 1.5 times that of the lower cervical VB [19].
The proatlas gives rise to the exoccipital bone and participates in the formation of the occipital condyle and the tip of the
odontoid process).
The head position is estimated on the basis of the craniocervical angle, which is formed by the basic anterior cranial base (NS), and
odontoid process tangent (OPT) which passes through the lower end last point on the body of the second cervical vertebra [2].
Of significance for this case, the
odontoid process was found to be 5 mm above Chamberlain's line.