Imaging description

Flexion and extension radiographs of the cervical spine can be used in the setting of blunt trauma to assess for stability if the initial imaging with cervical spine radiography or CT is normal. Patients with a normal Glasgow Coma Score (GCS) who are not intoxicated, but who complain of persistent posterior midline tenderness may undergo this dynamic test as an alternative to MRI [1].

Dynamic evaluation of the cervical spine has been performed for many decades and numerous radiographic findings have been described. Despite this long history of use, specific validated measurable criteria to determine what constitutes a normal or abnormal radiographic flexion-extension (FE) study do not exist. The usual practice is to assess intervertebral body motion (subluxation and angulation) to indirectly determine presence or absence of an unstable cervical spine injury (Figure 21.1). The criteria used are mostly derived from cadaver models with very limited validation data for the trauma setting [2]. A wide variation exists in the degree of physiologic range of motion between cervical levels, among individuals, at different ages, and between genders [3, 4].