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Age / Sex : 70 / F
Chief complaint: Neck pain and
posterior headache (onset: 20 years ago, 1 year ago aggravation)
What is your impression?
Two weeks later, you can see the final diagnosis with a brief discussion of
this case.
(Please submit only one answer)
Courtesy: Jong
Won Kwon, Samsung medical center Seoul hospital
Diagnosis: Atlanto-occipital assimilation with basilar invagination
Discussion
Findings:
1.
occipitalization of atlas (atlas assimilation)
2. basilar invagination
and C1-2 subluxation
3.
associated stenosis of the foramen magnum and compression of medulla oblongata
4.
compressive myelopathy at C2 level
Differential Diagnosis:
Diagnosis:
Atlanto-occipital
assimilation with basilar invagination
Discussion:
*Atlanto-occipital
Assimilation (=Occipito-atlantal fusion)
- Partial or
total fusion of the atlas to the occiput
- Posterior elements
of the atlas may be hypoplastic and anomalous
- Associated
with basilar invagination & C2 ~ C3 fusion (Klippel-Feil syndrome) (70%),
Chiari type I malformation with syringomyelia, Atlantoaxial subluxation (50%)
- Associated
with syndrome: Achondroplasia, diastrophic dwarfism, spondyloepiphyseal
dysplasia, Larsen syndrome, Morquio syndrome
* Basilar
invagination/ Impression
- The floor of the skull is indented or has been violated by the upper cervical
spine, usually the odontoid, which may sit within the foramen magnum
- The tip of dens is >5mm above the Chamberlain’s line, >7mm above the
McGregor’s line
References:
Craniovertebral
junction: normal anatomy, craniometry, and congenital anomalies. Smoker WR. Radiographics.
1994 Mar;14(2):255-77.
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