Segmental vertebral motion in the assessment of neck range of motion in whiplash patients.

The purpose of this study was to obtain comparative data concerning the relative contribution of segmental cervical vertebral motion to the cervical range of motion (ROM) in whiplash and healthy subjects in an effort to evaluate the usefulness of X-ray analysis in future forensic and research efforts. Each subject's neck ROM was measured with an optoelectronic system and also by X-ray measurements of the angular rotation in flexion and extension. The X-rays were examined to calculate the angular movement in the sagittal plane of each of the functional units C2-C3 to C6-C7. The chronic whiplash subjects showed reduced total neck range in all directions as compared to healthy subjects (p<0.001). There was a reduced total angular rotation from flexion to extension between these two groups (p<0.01), but no significant difference, however, between chronic whiplash subjects and controls in the percentage contribution of each of the functional units C2-C3 to C6-C7 to this rotation. This data will now allow a design of trials where healthy subjects are asked to simulate restricted neck ROM while undergoing optokinetic and X-ray evaluation of segmental vertebral motion. We will be able to determine if simulators produce a similar pattern to chronic whiplash and healthy, non-simulating subjects, and thus determine if, at least for forensic and research purposes, this technique is useful in validating reported restricted neck range.