Prevertebral soft-tissue measurements in cervical spine injury.

To clarify normal values for cervical prevertebral soft-tissue measurements and evaluate when they are useful as a marker of cervical spine injury, the prevertebral soft-tissue measurements of 79 control and 57 acutely injured patients were retrospectively compared by two independent observers. The second, blinded, observer made a provisional diagnosis and indicated if increased soft-tissue measurements had assisted in making a diagnosis of injury. If measurements > 7 mm at C2/3 and > 21 mm at C6/7 were considered abnormal, a true positive rate of 53% and false positive rate of 5% were observed. The differences between the mean measurements in the control and injured groups were statistically significant (P < 0.0001 at C2/3 and P < 0.01 at C6). Soft-tissue measurement improved the diagnostic confidence of the blinded second reviewer in 17.5% of the injured group. Analysis of this subgroup revealed a 50% error rate in initial reporting. In all of these cases, the abnormal soft-tissues had been ignored prospectively Routine measurement of the prevertebral soft tissues is a simple procedure that may provide an important due to subtle cervical spine injury.