Traumatic posterior atlantoaxial dislocation without related fractures of C1-C2
A 32 year old man presented with pain and stiffness in the neck, difficulty in breathing associated with lacerations on face and deformity of mandible with inability to open the mouth following trauma. He was travelling in a car which was hit to a parked lorry from the side. There was no history of unconsciousness or signs of head injury. The neurological examination showed no apparent neural deficit. Emergency tracheostomy was performed.\nOn secondary survey, the patient was well oriented to time and space with no evidence of concomitant chest, abdominal or head injuries except laceration on his face with fracture of mandible. The flexion/extension and rotation of the neck, along with opening of mouth were restricted. The patient did not have any signs of generalized ligamentous laxity.\nRadiographs of the cervical spine demonstrated a posterior dislocation of the atlas with respect to the axis [] with no evidence of fracture. The C7 vertebra was not visualized due to overlap of the shoulders. Magnetic resonance imaging (MRI) [] of the cervical spine demonstrated no cord compression or intramedullary cord signal abnormality at the level of the atlantoaxial dislocation. The membrana tectoria/apical and transverse ligament at lateral attachment of dens was torn. Superior transverse ligament was found intact. Computed tomography (CT) of the spine showed anterior displacement of C2. The dens was situated anterolateral to the anterior arch of C1 with facet joint dislocation of C1-C2. There was diffuse prevertebral soft tissue shadow seen from C1 to C4 level. A tiny fracture fragment seen adjacent to odontoid process. Atalanto-occipital joint appeared normal. Body and posterior arch of C2 appeared normal. Occipital condyles and rest of visualized cervical spine appeared normal. Comminuted displaced fracture was seen involving the angle and ramus of mandible on the right side.\nClosed reduction on skeletal traction under anesthesia was attempted with help of image intensifier [] and neurological monitoring by Wong three-step method.[]\nTraction is applied in slight flexion to keep C1 ring apposed to posterior odontoid.\nThe C1 ring has slipped back over the odontoid but is displaced too far forward because of slightly excessive flexion angle of traction.\nTraction is changed to slight extension, allowing the C1 ring to come closer to anterior odontoid. Traction is then released over several hours.\nThe attempt of closed reduction failed. We had to proceed for open reduction with posterior stabilization and fusion [].