Do MRI findings correlate with mobility tests? An explorative analysis of the test validity with regard to structure.

To find out whether segmental magnetic resonance imaging (MRI) findings such as intervertebral disc degeneration (DD) and facet joint osteoarthritis (FJO) are associated with motion deficiencies as seen in common mobility tests and observed range of motion (ROM). A total of 112 female subjects, nurses and office workers, with and without low back pain, were examined by clinical experts, and lumbar mobility was measured including modified Schober, fingertip-to-floor distance (FTFD) and ZEBRIS motion analysis. An MRI of the lumbar spine was made. Mobility findings were correlated with segmental morphologic changes as seen on MRI at the levels of L1-2 through L5-S1. Only a few statistically significant correlations between MRI findings and the results of the mobility tests could be found. Lateral bending was weakly and negatively correlated to DD and FJO but only on the level of L5-S1. The FTFD showed a weak positive correlation to endplate changes on the level of L4-5. When ROM is observed by clinical experts, there are several significant relationships between MRI findings and the observed motion. There is a highly significant segmental correlation between DD and disc form alteration as seen on MRI on the level of single motion segments. Pain history and current pain level did not moderate any association between MRI and mobility. There is no clear relationship between the structural changes represented by MRI and the measured mobility tests used in this study. Our findings suggest that close observation of spinal motion may provide at least equal information about the influence of spinal structures on motion than the commonly used measured mobility tests do.

Validity of pressure pain thresholds in female workers with and without recurrent low back pain.

Recurrent low back pain (LBP) is a common pain condition in elderly workers in a variety of occupations, but little is known about its origin and the mechanisms leading to an often disabling sensation of pain that may be persistent or intermittent. In the present study we evaluated the pressure pain thresholds (PPTs) in subjects suffering from recurrent LBP, as well as in healthy controls, to investigate if recurrent LBP is associated with an increased sensitivity of the muscular and ligamentous structures located on the lower back. One hundred and six female workers, aged between 45 and 62 years and working either in administrative or nursing professions were examined. The subjects were classified into LBP cases and controls based on the Nordic questionnaire. Subjects indicating 8-30 or more days with LBP during the past 12 months were graded as cases. PPTs were measured on 12 points (six on each side of the body) expected to be relevant for LBP (paravertebral muscles, musculus quadratus lumborum, os ilium, iliolumbar ligament, musculus piriformis and greater trochanter), as well as on a reference point (middle of the forehead) using a digital dolorimeter. The PPTs on all points on the lower back highly correlated with each other and a high internal consistency was found with a Cronbach alpha coefficient > 0.95. There was a moderate and significant correlation of the PPT on the forehead with the PPT on the lower back with correlation coefficients ranging from 0.36 to 0.49. In LBP cases from administrative professions, the PPT on the forehead was significantly decreased (P < 0.05). The PPT on the lower back did not significantly differ between the four groups studied, namely nurses and administrative workers with and without recurrent LBP. These results give evidence that recurrent LBP is not associated with an altered sensitivity of the muscular and myofascial tissues in the lumbar region. Furthermore, they raise questions about the value of reference point measurements in recurrent LBP.