Epidemiology of spinal cord injury after acute odontoid fractures.

OBJECT: Cervical spinal cord injury (SCI) after odontoid fracture is unusual. To identify predisposing factors, the authors evaluated a consecutive series of patients who sustained SCI from odontoid fractures.
METHODS: A consecutive series of 5096 admissions to the Delaware Valley Regional Spinal Cord Injury Center were reviewed, and 126 patients with neurological impairment at the C1-3 levels were identified. Seventeen patients had acute closed odontoid fractures with neurological deficit. Various parameters including demographics, mechanisms of injury, associated injuries, fracture types/displacements, and radiographic cervical canal dimensions were compared between "complete" and "incomplete" spinal cord injured-patients as well as with neurologically intact patients who had suffered odontoid fractures. There were similar demographics, mechanisms of injury, associated injuries, fracture type/displacement, and canal dimensions in patients with complete and incomplete SCIs. However, only patients with complete injury were ventilator dependent. In comparison with patients with intact spinal cords, spinal cord-injured patients were more commonly males (p = 0.011) who had sustained higher velocity injuries (p = 0.027). The computerized tomography scans of 11 of 17 neurologically impaired patients were compared with those of a random sample of 11 patients with intact spinal cords. Although the anteroposterior diameter (p = 0.028) and cross-sectional area (p = 0.0004) of the cervical spinal canal at the C-2 level were smaller in impaired patients, the displacement of the fragment was not different.
CONCLUSIONS: Odontoid fractures are an infrequent cause of SCI. Patients with these injuries typically are males who have smaller spinal canals and have sustained high velocity injuries.