Neurosurgery Resident Inova Fairfax Medical Campus Falls Church, Virginia, United States
Introduction: Atlanto-occipital dislocation (AOD) is a rare cervical spine injury associated with high morbidity and mortality, often resulting in immediate death at the time of initial trauma. In the setting of improved pre-hospital recognition and management, increasing survival rates make establishment of a timely diagnosis a critical factor in patient outcomes. Despite its clinical significance, diagnosis remains a clinical challenge.
Methods: Retrospective evaluation was performed on four patients presenting with atlanto-occipital dislocation: two in the setting of high velocity trauma, one from a ground level fall, and another from a fall down stairs. The most common diagnostic techniques for AOD were reviewed and summarized. Modern diagnostic techniques including measurement of the basion-dental interval (BDI), basion-axial interval (BAI), condylar-C1 interval (CCI), Powers’ ratio, and X-line method were applied to each case.
Results: In each described case, at least one reported diagnostic technique for atlanto-occipital dislocation was falsely negative. Each clinical case was ultimately managed using similar techniques with overall favorable clinical outcomes. The proposed MRI grading system identified the presence of injury in each of the illustrative cases.
Conclusion : Atlanto-occipital dislocation is a catastrophic injury with increasing rates of survival to the hospital setting. The reported cases illustrate the complexity and shortcomings of current modern diagnostic methods in identifying AOD. Subsequently, we propose an additional method for diagnosis which utilizes MRI findings, emphasizing critical ligaments stabilizing the atlanto-occipital joint (anterior and posterior atlanto-occipital, apical, transverse ligaments, as well as the tectorial membrane). Ultimately, multiple diagnostic modalities should be employed as reliance on individual metrics may lead to false negatives.
