Are subjective clinical findings and objective clinical tests related to the motion characteristics of low back pain subjects?

Many authors have demonstrated that low back pain sufferers have impaired spinal motion. However, it is not known to what degree the patient's signs and symptoms influence this impairment in motion. The aim of this study was therefore to conduct an explorative study to investigate the relationship between low back pain patients' signs and presenting symptoms and objective measurements of motion. One hundred thirty-eight patients with low back pain completed a questionnaire detailing their signs and symptoms and underwent a full clinical examination. A potentiometric motion analysis system of known accuracy and repeatability was used to measure their spinal motion during a flexion-extension test. The effects of a variety of subjective and clinical findings on the motion characteristics were examined, which revealed that certain factors, such as diagnosis, pain characteristics, symptom severity, and level of disruption, were related to the resulting motion measurements. The strength of these relationships were not as strong as anticipated (accounting for 16-45% of the variability). This suggests that routine objective assessments cannot be used as a substitute for a thorough physical and subjective examination.