The value of functional computed tomography in the evaluation of soft-tissue injury in the upper cervical spine.

A functional rotatory computed tomography (CT) study of 423 whiplash patients with cervical spine soft-tissue injury was undertaken to determine its diagnostic value. The results are correlated with previous CT studies on normal subjects, and an evaluation of paradox motion, in which the lower vertebra rotates more than the vertebra immediately superior to it, is given. Asymmetrical left/right rotation reached the pathological value in 36% of the patient population at the level of C0-1. Twice as many patients had hypermobile rotation to the left as compared with the right, perhaps indicating that the right alar ligament is more often damaged in injuries involving the whiplash mechanism. A higher percentage of pathological values for hypermobile rotation was found at the level of C0-1 than at C1-2. Patients exhibiting paradox rotation had a significantly higher amount of rotation to the contralateral side than did those who exhibited no paradox rotation. These findings validate the use of functional rotatory CT in the evaluation of soft-tissue damage of the upper cervical spine resulting from whiplash injury.