Controversies in Spine Surgery

INTRODUCTION: Odontoid process fractures in elderly patients are common and significant for their poor clinical and radiologic prognosis. This controversy debates the role of MRI in odontoid process fractures in elderly patients without a neurological deficit. CONTROVERSY: Elderly patients generally sustain odontoid process fractures following low-energy mechanisms. Ligamentous structures provide a significant secondary constraint to progressive fracture displacement. The additional contribution of MRI after CT and/or radiographs is controversial. SUMMARY: Potentially the most justifiable reason for getting an MRI in the setting of an odontoid process fracture in a neurologically intact elderly patient is to identify occult adjacent segment injury, particularly in the setting of advanced degenerate disease or ankylosis. This debate is useful in guiding imaging criteria and hypothesis generation, particularly the role of discrete MRI findings as indicators for surgery. The authors suspect that ligamentous injury findings are nuanced in their predictive features; ie, anterior longitudinal ligament disruption in extension fractures and posterior longitudinal ligament disruption in flexion injuries. Translational work to demonstrate CT thresholds which are consistent with MRI-confirmed ligamentous injury may give the ability to anticipate ligamentous injury on CT alone. This is of high importance in healthcare systems where access to MRI is limited.