Association between measures of spinal mobility and low back pain. An analysis of new attenders in primary care.

STUDY DESIGN

Comparison of spinal movements in new attenders to primary care with an episode of low back pain with a sample with no recalled history of ever having had low back pain.

OBJECTIVES

To examine the association between restriction of spinal movement and the presence of low back pain in primary care.

SUMMARY OF BACKGROUND DATA

The presence of restriction in spinal mobility has frequently been investigated by specialists in the clinical setting. What is not known, however, is whether an association exists between pain and restriction in those newly presenting to primary care and whether these measurements can be used to discriminate between those with and without back pain.

METHODS

The study participants consisted of 344 consulters to two general practices, prospectively ascertained in the South Manchester Back Pain Study, who were compared with 118 individuals from the same practices who denied ever having back pain. The two groups were compared for right and left lateral flexion, standing extension, modified Schober's test, finger-to-floor distance, and right and left knee extension.

RESULTS

There was a statistically significant reduction in all planes in those with low back pain. Modified Schober's, standing extension, and left knee extension were the most discriminatory, with likelihood ratios of approximately 5 for the optimal cutoff. Restriction of three or more of these seven movements was observed in 50% of the low back pain cases and in less than 5% of the pain-free participants. Stratification by presence or absence of radiation of pain to the legs did not alter these findings.

CONCLUSIONS

Measures of spinal mobility are restricted to varying extents in a community-based sample of subjects with low back pain. Maximal discrimination was observed when restriction was present in three or more planes. The utility of these measures in predicting outcome remains to be assessed.