MRI Unnecessary in Evaluation of Odontoid Fracture
Transverse atlantal ligament injury not seen following screw fixation with odontoid fracture
MONDAY, Oct. 20 (HealthDay News) -- Because no cases of late instability were discovered following anterior screw fixation for odontoid fracture to suggest the presence of transverse atlantal ligament (TAL) injury, MRI screening for TAL injury is unnecessary, according to a report in the October issue of the Journal of Spinal Disorders & Techniques.
Christina M. Sayama, M.D., of the University of Utah in Salt Lake City, and colleagues performed a retrospective radiographic review to determine if late TAL injury was associated with type II and shallow type III odontoid fractures treated with anterior screw fixation at the University of Utah from 1987 to 2006. Prior research indicated TAL injury in as much as 10 percent of odontoid fractures and recommended preoperative MRI prior to screw fixation. For the purpose of this study, an atlantodental interval (ADI) greater than 3 mm on neutral, flexion or extension films indicated possible TAL injury.
Overall, 77 patients had neutral follow-up radiographs and 34 patients had follow-up flexion/extension films with a mean follow-up of 17.5 and 16.4 months, respectively. Average ADI with neutral, flexion and extension films was 1.1 mm, 1.2 mm, and 1.2 mm, respectively, with no measurements greater than 3 mm to suggest any TAL disruption, the researchers report.
"The results of this study question the need to obtain MRI to evaluate all patients with an odontoid fracture for TAL injury as has been previously published," the authors conclude. "In our experience, patients with odontoid fractures do not require MRI screening unless there are neurologic deficits or ADI widening on plain radiographs or computed tomography images to suggest TAL injury.