Atlantoaxial Rotatory Subluxation

Atlantoaxial rotatory subluxation can be idiopathic or be due to infection (pharyngitis or otitis media), recent head or neck surgery, or trauma. When an infectious etiology is present, the condition is referred to as Grisel syndrome.

Fielding and Hawkins classified atlantoaxial rotatory subluxation into 4 types:

• Type I: Simple rotatory displacement without anterior shift. The transverse ligament is intact and the dens acts as a pivot point.
• Type II: Rotatory and anterior displacement between 3-5 mm. The transverse ligament is injured and the opposite facet acts as the pivot point.
• Type III: Rotatory and anterior displacement greater than 5 mm with both lateral atlantoaxial joints anteriorly subluxed. The transverse ligament and facet capsules are injured.
• Type IV: Posterior subluxation of both lateral atlantoaxial joints. Rare and described in adult patients with rheumatoid arthritis and destruction of the dens.

Diagnosis of rotatory subluxation is made with dynamic CT of the upper cervical spine in neutral, head to the left, and head to the right positions. Fixed rotatory subluxation is diagnosed if the distance from the dens to a C1 anterolateral arch on one side is persistently widened on all images compared to the other side.

Management ranges from conservative to surgical, depending on patient age and the duration of symptoms. Children with acute symptoms can be treated with manual reduction followed by mechanical traction (with a hard cervical collar or with weighted traction). Children with a subacute presentation or recurrence are treated with open fixation. Adults are generally treated surgically.

References

• Fielding JW, Hawkins RJ. Atlanto-axial rotatory fixation. (Fixed rotatory subluxation of the atlanto-axial joint). J Bone Joint Surg Am. 1977 Jan;59(1):37-44.
• Lustrin ES, Karakas SP, Ortiz AO, Cinnamon J, Castillo M, Vaheesan K, Brown JH, Diamond AS, Black K, Singh S. Pediatric cervical spine: normal anatomy, variants, and trauma. Radiographics. 2003 May-Jun;23(3):539-60.
• Subach BR, McLaughlin MR, Albright AL, Pollack IF. Current management of pediatric atlantoaxial rotatory subluxation. Spine (Phila Pa 1976). 1998 Oct 15;23(20):2174-9.