Chronic type 2 odontoid fracture with atlantoaxial spondyloptosis in an adult: a case report and literature review.

Background: Type 2 odontoid fractures may be associated with varying degrees of atlantoaxial dislocation (AAD). Atlantoaxial spondyloptosis (AAS) is a rare cervical injury with reported etiologies including congenital, trauma, and rheumatoid disease, defined as having the facets of the atlas fixed anteriorly to the facets of the axis. When associated with a type 2 odontoid fracture, there is complete translocation of the C1 arch and the fractured odontoid process complex, anteriorly to the C2 vertebral body, representing a severe form of fixed or irreducible anterior AAD. The challenging anatomy increases the complexity of surgical decision-making, while the paucity of reported cases increases the challenge in deriving guidance to inform the surgical approach. This report adds to the limited literature on AAS and highlights a unique surgical management strategy. Case Description: This report presents the case of an adult patient with a chronic type 2 odontoid fracture and AAS after low-impact trauma in the setting of newly diagnosed inflammatory comorbidities of sarcoidosis and latent tuberculosis. The patient had neck pain attributable to the atlantoaxial pathology but was otherwise neurologically intact. The patient was successfully managed with an occipitocervical fusion and posterior decompression without reduction, with resolution of the neck pain. Conclusions: The choice of surgical approach should be made based on careful preoperative radiographic evaluation of fracture-dislocation morphology and associated vascular anatomy, in addition to patient-specific factors. In the absence of neurological deficits, reduction of the fracture-dislocation may be deferred in favor of stabilization with decompression.