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Archived Comments for: Segmental lumbar mobility in individuals with low back pain: in vivo assessment during manual and self-imposed motion using dynamic MRI

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  1. Concern about Analysis of Results and Conclusion

    Christopher Good, University of Bridgeport College of Chiropractic

    9 March 2007

    I was fascinated by the technology used to investigate spinal motion, well done! However, by choosing 2SDs as the point that would categorize a functinal spinal unit (FSU) as hypomobile, some important data was probably lost, and this affected the conclusion. Specifically, in the case of P-A testing a FSU had to have less than 1 degree of measured movement to be classified as hypomobile (for the L3/L4 motion unit it had to have 0 degrees of movement). More problematic, for the Push Up Group, the FSUs had to exhibit even less movement (less than .5 degrees, and the standard error of measurement was .5 as well). In particular the L2/L3 level had to exhibit -.9 degrees of movement, making it virtually impossible for this level to ever be classified as hypomobile (unless it exhibited paradoxical motion, presumably). These are such small amounts of motion for an early middle age group, they don't seem acceptable as category limits, especially considering the measurement error. One could argue that a FSU that has lost 50% of its movement is a more reasonable indicator of hypomobility, and in this study that would be approximately 2 degrees.

    Also, what might be useful is to look at different amounts of motion at FSUs within the same symptomatic subject, identifying relative hyper- and hypo- mobility at FSUs, correlating this with the site of pain, and then comparing these findings with an asymptomatic group. This would mirror clinical practice more closely.

    Competing interests