Neck mobility assessment in ankylosing spondylitis: a clinical study of nine measurements including new tape methods for cervical rotation and lateral flexion.

The objective was to carry out a clinical assessment of different cervical mobility measurements in ankylosing spondylitis (AS), including two new tape methods for measuring cervical rotation and lateral bending. A range of cervical movements was measured in 52 consecutive male AS patients and the results correlated with detailed radiological changes in the whole spine and sacroiliac joints. Occiput- and tragus-to-wall distance (OWD/TWD), cervical rotation (CR) and lateral flexion (CLF) using a Myrin inclinometer (My) and a tape method (t), cervical flexion-extension (CFl-CExt/My) motion and chin chest distance (CCD) measurements were taken and repeated (test-retest). The results showed a highly significant correlation of all measurements with cervical radiological changes, except for CCD, and also those of OWD/TWD with lumbar changes. CLF and CExt also correlated significantly with lumbar changes, other measurements did not, and only TWD and CExt correlated with thoracic changes. All measurements showed good reliability, intra-class correlation coefficients (ICC) ranging from 0.89 to 0.98. Occiput- or tragus-to-wall distance, cervical extension and lateral flexion proved to be valid and reliable measurements in AS, but cervical rotation also appeared to be a clinically relevant method. Cervical lateral flexion is a recommendable measurement for clinical trials in AS. The two new tape methods for measuring cervical rotation and lateral bending were as valid and reliable as the inclinometer method (Myrin), but also quick and easy. Chin-to-chest distance was not among the most valid tests in AS.