Lisa was also diagnosed with Atlanto-Axial Instability
(AAI) which is a complication of EDS that results from excessive movement.
Lobato, "Pannus resolution after occipitocervical fusion in a non-rheumatoid atlanto-axial instability
," European Spine Journal, vol.
The abnormalities documented in the cervical region were 8 hemivertebrae (C5 2x, C6 3x, C7 3x) followed by four dogs with atlanto-axial instability
, and one dog with block vertebrae (C2-C3).
Approximately 50% of patients with atlanto-occipital fusion develop atlanto-axial instability
(3) The majority of asymptomatic individuals are neurologically intact and only some present with incidentally discovered atlanto-axial instability. (4)
(2) However, one study reported that symptomatic atlanto-axial instability can develop over time, even after a diagnosis of a 'stable' os odontoideum is made.
Cervical Paget Disease of Bone with Spinal Cord Compression due to Atlanto-Axial Instability
. Spine 2008;33(3):85-89.
C2 (between C1 and C2) typically causes peri-auricular (ear) pain and is most frequently present in rheumatoid arthritis patients with atlanto-axial instability
from inflammatory joint destruction.
"It hadn't occurred to us that Ben needed this test, an atlanto-axial instability
Additionally, individuals with Down's syndrome are at risk of Atlanto-axial instability
, which is an increased mobility of the atlas and axial bones, located directly under the skull.
among people with Down's syndrome Web site: http://www.dsmig.org.uk/library/articles/dsa-medical-series3.pdf Accessed August 26, 2008.
Due to the high incidence of atlanto-axial instability
in cases of os odontoideum, cervical flexion-extension radiographs should be obtained to document the degree of instability.