Study Design: Retrospective study.
Objectives: To analyze the usefulness of flexion-extension radiographs in the diagnosis of degenerative cervical disease.
Summary of Literature Review: There is little information about the efficacy of flexion-extension radiographs in the diagnosis of degenerative cervical disease.
Methods and Materials: We analyzed 1,062 patients with cervical degenerative disease who underwent flexion-extension radiographs and computed tomography (CT) or magnetic resonance imaging (MRI). The range of motion of the cervical joints was measured.
Segmental instability was evaluated using the sagittal translation (≥3.5 mm) between C2 and T1, the sagittal angulation (≥3.5°), the vertebral slip angle (≥ 10°), and the dynamic spinal canal stenosis (≤12 mm). The relationship between canal compromise on CT or MRI and radiological instability was also evaluated.
Results: Cervical range of motion was 36.45°±17.63° (range, 2.1°-106.6°). Segmental instability was observed in 484 patients (nine cases of sagittal translation, 79 cases of sagittal plane rotation, 415 cases of a vertical slip angle, and 21 cases of dynamic spinal stenosis). Segmental instability was related with pathology in 218 patients with available CT or MRI (42%, including five cases of sagittal translation, 32 cases of sagittal plane rotation, 171 cases of vertical slip angle, and 10 cases of dynamic spinal stenosis.
Conclusions: Flexion-extension radiographs of the cervical spine were useful in diagnosing and evaluating subaxial segmental instability.