Traumatic Atlanto-occipital Dislocation

Study design Retrospective case analyses. Objective The aim of this study was to investigate the incidence and characteristics of associated upper cervical spine injuries in 15 survival cases of traumatic atlanto-occipital dislocation (AOD). Summary of background data Traumatic AOD is a rare and generally fatal injury. Information regarding associated upper cervical spine injuries that may affect treatment methods, outcomes, and prognosis is limited. Methods Fifteen patients (11 patients with posterior-type AOD and four patients with vertical-type AOD) who survived traumatic AOD were included in this study. Plain radiographs, computed tomography, magnetic resonance imaging, and medical records were reviewed. The incidence and characteristics of associated upper and lower cervical spine and thoracolumbar spine injuries and brain injuries were evaluated. Results Thirteen patients with traumatic AOD (11 patients with posterior-type AOD and two patients with vertical-type AOD) showed associated upper cervical spine injuries; the overall incidence was 87% (100% in posterior-type AOD and 50% in vertical-type AOD). In posterior-type AOD, eight (72.7%) patients had C1 fractures (four patients had three-part fracture, three patients had two-part fracture, and one patient had four-part fracture), four (36.4%) patients had C1 lateral mass fractures, two (18.2%) patients had transverse atlantal ligament injuries. In vertical-type AOD, two (50%) patients had C1-C2 vertical subluxation with C1 anterior arch horizontal and sagittal split fractures. In posterior-type AOD, two (18%) patients had lower cervical spine injuries and one (9%) patient had brain injury. In vertical-type AOD, one (25%) patient had thoracic spine injury, and three (75%) patients had brain injuries additionally. Conclusion Survival cases with traumatic AOD showed a high incidence of associated upper cervical spine injuries and brain injuries. High index of suspicion and careful radiologic examination are needed to investigate the presence of associated upper cervical spine injuries and brain injuries in traumatic AOD, which affects treatment, outcome, and prognosis. Level of evidence 4.