Intra-operator and inter-operator reliability of the OSI CA 6000 Spine Motion Analyzer with a new skin fixation system.

Following the independent development in the University of Brighton of a new skin fixation system for use with the OSI CA 6000 Spine Motion Analyzer, a series of studies were initiated to test the reliability of the instrument with the new skin fixation system, and the repeatability of the results thus obtained. This paper reports on the outcome of an initial pilot study to compare the existing manufacturer-supplied strap fixation system with the new system. This was followed by a second pilot study to establish single intra-operator reliability utilising 23 asymptomatic subjects. Following successful conclusion of the pilot studies, full inter/intra-operator reliability studies were initiated, utilising 11 asymptomatic subjects. The mean ranges of motion obtained from these results are reported and analyses of variance were used to calculate Intra-class Correlation Coefficients (ICCs) as an indication of reliability. These are summarised as follows: flexion/extension ranges 0.807; lateral flexion ranges 0.923; rotation ranges 0.822. A detailed methodology is explained, along with in-depth discussion of the reasoning behind its adoption, and detailed discussion of the results obtained. This study forms a foundation for the establishment of normative data for ranges of motion and patterns of movement in the lumbar spine, as part of a long-term programme of work investigating the effects of low back pain in specific occupational groups on lumbar spine ranges of motion. It is concluded that the results reported justify progression to the collection of normative data for the lumbar spine, utilising the CA 6000 Spine Motion Analyzer with the new skin fixation system, and the widespread application of that data in the clinical setting.