Diagnostic Accuracy of Videofluoroscopy for Symptomatic Cervical Spine Injury Following Whiplash Trauma

Abstract

Background: Intervertebral instability is a relatively common finding among patients with chronic neck pain after whiplash trauma. Videofluoroscopy (VF) of the cervical spine is a potentially sensitive diagnostic tool for evaluating instability, as it offers the ability to examine relative intervertebral movement over time, and across the entire continuum of voluntary movement of the patient. At the present time, there are no studies of the diagnostic accuracy of VF for discriminating between injured and uninjured populations.

Methods: Symptomatic (injured) study subjects were recruited from consecutive patients with chronic (>6 weeks) post-whiplash pain presenting to medical and chiropractic offices equipped with VF facilities. Asymptomatic (uninjured) volunteers were recruited from family and friends of patients. An ethical review and oversight were provided by the Spinal Injury Foundation, Broomfield, CO. Three statistical models were utilized to assess the sensitivity, specificity, positive and negative predictive values (PPV and NPV) of positive VF findings to correctly discriminate between injured and uninjured subjects.

Results: A total of 196 subjects (119 injured, 77 uninjured) were included in the study. All three statistical models demonstrated high levels of sensitivity and specificity (i.e., receiver operating characteristic (ROC) values of 0.71 to 0.95), however, the model with the greatest practical clinical utility was based on the number of abnormal VF findings. For 2+ abnormal VF findings, the ROC was 0.88 (93% sensitivity, 79% specificity) and the PPV and NPV were both 88%. The highest PPV (1.0) was observed with 4+ abnormal findings.

Conclusions: Videofluoroscopic examination of the cervical spine provides a high degree of diagnostic accuracy for the identification of vertebral instability in patients with chronic pain stemming from whiplash trauma.

Keywords: digital motion x-ray; instability; positive predictive value; videofluoroscopy; whiplash.

Figure 1

Exemplar of AP open mouth left lateral flexion view of C1 on C2, demonstrating normal alignment. The dashed line indicates the lateral border of the left lateral mass of C1, and the solid line indicates the lateral border of the left articular pillar of C2. The 2 lines are aligned, indicating no translation of C1 on C2 with maximal voluntary left lateral flexion. Note: the image has been reversed so that left on the image corresponds with the patient’s left.

Figure 2

Exemplar of AP open mouth left lateral flexion view of C1 on C2, demonstrating abnormal alignment. The dashed line indicates the lateral border of the left lateral mass of C1, and the solid line indicates the lateral border of the left articular pillar of C2. The red arrow indicates 8 mm lateral translation of C1 on C2 during maximal voluntary lateral flexion. Note: the image has been reversed so that left on the image corresponds with the patient’s left.

Figure 3

Exemplar of lateral cervical flexion view, demonstrating normal alignment of C2 on C3. The dashed line indicates the posterior margin of the vertebral body of C2, and the solid line indicates the posterior margin of the vertebral body of C3. The 2 lines are aligned, indicating normal alignment of C2 on C3 upon maximal voluntary flexion.

Figure 4

Exemplar of lateral cervical flexion view, demonstrating abnormal alignment of C2 on C3. The dashed line indicates the posterior margin of the vertebral body of C2, and the solid line indicates the posterior margin of the vertebral body of C3. The red arrow indicates 5 mm of anterior translation of C2 on C3 upon maximal voluntary flexion, which is limited due to pain.

Figure 5

Diagnostic accuracy results for Model 3.