Citation, DOI, disclosures and article data
Citation:
Iqbal S, Yap J, azimi m, et al. Odontoid process agenesis. Reference article, Radiopaedia.org (Accessed on 30 Sep 2023) https://doi.org/10.53347/rID-87627
Odontoid process agenesis is rare, occurring due to a lack of failure of ossification of the odontoid process. It is seen in patients with spondyloepiphyseal and spondylometaphyseal dysplasia 1,2.
Radiographic features
Plain radiograph
On plain film, odontoid process agenesis appears as a slight depression between the superior articular facets on open mouth view, or hypogenesis of the basal segment of the odontoid with a floating apical process. Both of these conditions are associated with atlantoaxial instability.
CT
On dynamic CT, both flexion and extension views should be performed to identify posterior subluxation.
Treatment and prognosis
Atlantoaxial instability will lead to vascular compression and stroke because of ischemia 2,4. Treatment options include surgical fusion of C1 and C2.
See also
- 1. Jain N, Verma R, Garga UC, Baruah BP, Jain SK, Bhaskar SN. CT and MR imaging of odontoid abnormalities: A pictorial review. (2016) The Indian journal of radiology & imaging. 26 (1): 108-19. doi:10.4103/0971-3026.178358 - Pubmed
- 2. Cormier DV, Cormier. Spondylo-epi-metaphyseal dysplasia. (2008) Best practice & research. Clinical rheumatology. doi:10.1016/j.berh.2007.12.009 - Pubmed
- 3. Ishak B, Ishak DG, Ishak RR, Ishak ME, Ishak MM, Ishak IJ, Ishak BC, Ishak DA, Ishak TR, Ishak. The Retroverted Dens: A Review of its Anatomy, Terminology, and Clinical Significance. (2020) World neurosurgery. doi:10.1016/j.wneu.2020.01.231 - Pubmed
- 4. Kyoshima K, Kyoshima KY, Kyoshima TK, Kyoshima AK, Kyoshima KM, Kyoshima KT, Kyoshima. Odontoid compression of the brainstem without basilar impression-- "odontoid invagination". (2005) Journal of clinical neuroscience : official journal of the Neurosurgical Society of Australasia. doi:10.1016/j.jocn.2004.07.022 - Pubmed
- 5. Sureisen M, Achannan R, Chong KC, Wong CC. What the mind does not know, the eyes do not see: a rare congenital fusion of the odontoid process to the atlantal hemiarch. (2015) BMJ case reports. doi:10.1136/bcr-2015-212748 - Pubmed
Promoted articles (advertising)