O3276: Negative Predictive Value of a Normal Cervical Spine CT Compared to MRI for Ligamentous Injury After Blunt Trauma in children: a Western Pediatric Surgery Research Consortium Multi-center Retrospective Review

Background: Cervical spine injury in children is rare but potentially devastating. Clinical clearance is generally sufficient if a child has a reliable neurologic exam, but children with persistent cervical tenderness or an unreliable exam pose a challenge. Plain radiographs or computed tomography (CT) may identify fractures or malalignment, but children are known to have a much higher rate of isolated ligamentous injury relative to adults. Magnetic resonance imaging (MRI) is currently the gold standard to rule out unstable ligamentous injury for children. In obtunded adult trauma patients, a negative high-quality cervical spine CT is sufficient to rule out clinically significant injury, but this has not been validated in children. The goal of this study was to determine the negative predictive value of a normal CT to rule out clinically significant cervical spine injury in children after blunt trauma.

Methods: We conducted a ten-center retrospective cohort study over five years of all children less than 18 years old undergoing cervical spine MRI after blunt trauma. Imaging findings for plain radiographs and CT of the cervical spine were recorded and compared to MRI findings to calculate measures of diagnostic accuracy. All imaging for patients with injuries was reviewed by a neurosurgeon at the participating site and the injury was deemed stable or unstable. All injuries that required treatment with a cervical-thoracic orthotic (CTO), surgical fixation, or halo placement were considered unstable.

Results: The cohort included 2,663 children with an MRI. Bony imaging included 1,573 (59%) children with CT, 746 (28%) with plain radiographs, and 343 (13%) with both plain radiographs and CT. MRI was the only imaging performed in 687 (26%) children. The median age was 8 years (IQR 1-14). The most common mechanisms of injury were motor vehicle collision (27%, n=678), fall (25%, n=637), and child physical abuse (19%, n=490). The majority (63%, n=1,670) of children had an unreliable exam at initial evaluation. Injuries were noted in 1,080 (41%) children. CT imaging had higher sensitivity than plain radiographs and sensitivity for both modalities was lower in the subgroup of unexaminable patients (Tables 1 and 2). Most injuries diagnosed by MRI in the presence of normal bony imaging were stable injuries. Among children who had a normal cervical spine CT, six (0.4%) required surgical fixation, halo placement, or long-term CTO immobilization.

Conclusion: Clinically significant ligamentous injury in the setting of a normal cervical spine CT is rare in children after blunt trauma. CT imaging is not sufficient, however, to completely rule out many injuries. The risks of missed injury and premature collar removal need to be weighed against the risks of cervical collar-associated pressure injury and transporting unstable patients to MRI for definitive imaging.