Traumatic posterior atlantoaxial dislocation without associated fracture and neurological deficit.

Traumatic posterior atlantoaxial dislocation without related fractures of the odontoid process and anterior arch of the atlas is exceedingly rare, with only ten published cases reported so far in English literature. We report on a 44-year-old man with post-traumatic posterior displacement of the atlas with respect to the axis without any associated fractures and neurological deficit caused by a crush injury in earthquake. Radiographs, computed tomography and magnetic resonance imaging revealed posterior displacement of the atlas with the odontoid peg lying anterior and to the right of the anterior arch of the atlas. Partial odontoidectomy and posterior fixation with bone graft were performed in one-stage procedure after several unsuccessful attempts of closed reduction. The patient did not have neurological deterioration after operation.