Traumatic Posterior Atlantoaxial Dislocation without Related Fractures of C1 - C2 in a Patient with Traumatic Brain Injury: Case Report and Literature Review

It is exceptionally rare to have posterior atlanto axial dislocation without an associated atlas or odontoid fracture and very few cases have been reported in literature. We present a case of a 50 year old female pedestrian who was hit by car while crossing a road. She presented with a depressed level of consciousness and the Glasgow coma score of 12/15, pupils were equal and reactive to light and all limbs were moving equally. She had an extensive abrasion on the forehead which extended into scalp. CT scan showed a posterior dislocation of the atlas with respect of axis with no associated fractures of C 1 and C2. She had traumatic subarachnoid hemorrhage in the basal cisterns and multiple brainstem contusions. Closed reduction of the dislocation was done successfully under fluoroscopy guidance. MRI was done post reduction because funds were not available initially and it showed increased signal in the tectorial membrane and transverse and alar ligaments with mild cord oedema at the cervicomedullary junction. However, the patient post reduction began to deteriorate and eventually passed away before definitive treatment of her cervical-spine injury. The case is reported in view of its rarity and to review literature on this uncommon condition.