Atlantoaxial rotatory subluxation with ankylosis in an 11-year-old girl: a case report.
METHODS
Report of an 11-year-old girl with a left atlantoaxial rotatory subluxation and ankylosis found 20 months after she sustained a cervical injury.


OBJECTIVE
To describe the radiographic characteristics of this rare deformity assessed with a combination of spiral CT scan with multiplanar three-dimensional reformations and functional CT scan.


BACKGROUND
Atlantoaxial rotatory subluxation is a well-known condition, but its association with lateral C1-C2 ankylosis has not been reported to our knowledge.


METHODS
For a complete assessment of the dislocation, a combined morphologic volumetric and functional CT study was performed.


RESULTS
Spiral CT showed an atlantoaxial rotatory subluxation with lateral C1-C2 ankylosis. CT study also demonstrated a lateral C1-C2 subluxation and an ipsilateral occipitoatlantal subluxation. Cervical MRI showed no spinal cord compression despite the seriousness of the dislocation process.


CONCLUSIONS
Whereas "classic" spiral study with multiplanar and three-dimensional reformations allows precise assessment of relationships between the upper cervical vertebrae, as well as bony changes, a functional CT study is essential for cervical biomechanic assessment of rotational instabilities of the craniovertebral junction and upper cervical spine.
Redon
Hervé
H
Hotel-Dieu, Radiology Department, Nantes, France. hredon@club-internet.fr
Iacona
C
C
Lot
G
G
Laredo
J D
JD
D000844:Ankylosis / Q000000981:diagnostic imaging / Q000209:etiology*; D001268:Atlanto-Axial Joint / Q000000981:diagnostic imaging / Q000503:physiopathology*; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional; D004204:Joint Dislocations / Q000000981:diagnostic imaging / Q000209:etiology*; D019838:Neck Injuries / Q000150:complications*; D012399:Rotation; D036542:Tomography, Spiral Computed; D014103:Torticollis / Q000209:etiology*