Atlantoaxial instability
Atlantoaxial instability (AAI) is characterized by excessive movement at the junction between the atlas (C1) and axis (C2) as a result of either a bone or ligament abnormality.
It can be caused by congenital conditions, inflammatory conditions like rheumatoid arthritis, as a result of physical trauma, or infection.[1]
It often co-occurs with craniocervical instability (CCI).
In individuals without predisposing conditions, it is thought to be extremely rare.[2]
Symptoms[edit | edit source]
Risk factors and causes[edit | edit source]
Congenital causes[edit | edit source]
Rheumatoid arthritis[edit | edit source]
Chronic inflammation can cause laxity and stretching of the transverse ligament, the formation of a pannus, as well as bone erosion.[2]
Grisel’s syndrome[edit | edit source]
Grisel’s syndrome occurs following inflammation of the soft tissue as a consequence of infection or surgery. It is primarily seen in patients ages 5-12 but can also be seen in adults.[3]
Diagnosis[edit | edit source]
AAI is defined as an atlantodental (or atlantodens or atlas-dens) interval (ADI) of greater than 3 mm in adults and of greater than 5 mm in children as measured on plain radiography. The ADI is the distance between the odontoid process and the posterior border of the anterior arch of the atlas.
Treatment[edit | edit source]
See also[edit | edit source]
Learn more
References[edit | edit source]
- ↑ "Atlantoaxial Instability: Background, Pathophysiology, Etiology". November 10, 2019. Cite journal requires
|journal=(help) - ↑ 2.0 2.1 Lacy, Jordan; Gillis, Christopher C. (2019). "Atlantoaxial Instability". Treasure Island (FL): StatPearls Publishing. PMID 30137847. Cite journal requires
|journal=(help) - ↑ "Atlantoaxial Instability: Background, Pathophysiology, Etiology". November 10, 2019. Cite journal requires
|journal=(help)
