Atlantooccipital dislocation in motor vehicle side impact, derivation of the mechanism of injury, and implications for early diagnosis.

Numerous reports of atlantooccipital dislocations (AODs) have been described in frontal impacts and vehicle versus pedestrian collisions. Reports of survival after AOD in conjunction with side impacts have infrequently been reported in the literature. The objective of this study is to present a case of an AOD from a side impact vehicle collision, and deduce the mechanism of injury. A clinical and biomechanical reconstruction of the collision was performed to investigate the mechanism of the dislocation. A 51-year-old female was traveling in a four-door sedan and sustained a side impact collision with a compact pickup truck. At the time of extrication, the patient was neurologically intact with a Glasgow Coma Scale score of 15. After admittance to the hospital, the patient developed a decline in respiratory status, right mild hemiparesis, and left sixth-nerve palsy, and magnetic resonance imaging (MRI) and computed tomography (CT) reconstructions indicated a craniocervical dislocation. Surgical fixation was performed and all extra-axial hemorrhaging was evacuated. At discharge, the patient was neurologically intact on the left side, had right mild hemiparesis, left sixth-nerve palsy, and minor dysarthria. Survival rates of AODs have recently been increasing. Morbidity is still more prevalent, however. Due to the variety of symptoms that accompany AODs and the inconsistency of diagnostic imaging techniques, a thorough history of the etiology may lead to increased clinical suspicion of this injury and further raise survival rates.