Low back pain, somatic dysfunction, and segmental bone mineral density T-score variation in the lumbar spine.

Abstract

Identifying objective measures that correlate with somatic dysfunction palpatory findings will aid in establishing clinical relevance of the findings and provide outcome measures for future studies. To investigate the association of altered segmental lumbar vertebral mechanics (ie, somatic dysfunction) as assessed by palpation with bone mineral density (BMD) T-score variability in participants, some with chronic low back pain (CLBP) and others without low back pain (LBP). Individuals with CLBP and individuals without LBP were examined by 2 blinded examiners for the presence or absence of paraspinal tissue texture abnormalities, vertebral rotational asymmetry, anterior motion restriction, and tenderness from L1 to L4. All participants then received a dual-energy x-ray absorptiometry scan of the lumbar spine. Bone mineral density T scores were compared between the CLBP and non-LBP groups. Sixty-three individuals (16 CLBP, 47 non-LBP) participated in the study. Lumbar segments with perceivable rotational asymmetry had higher mean BMD T scores (95% confidence interval [95% CI]) than lumbar segments with no asymmetry (0.5 [0.4-0.7] vs -0.2 [-0.6 to 0.2], respectively; P=.002). Additionally, lumbar segments with anterior motion restriction had higher mean BMD T scores (95% CI) than lumbar segments with no motion restriction (0.6 [0.4-0.7] vs 0.1 [-0.2 to 0.3], respectively; P=.03). Participants with CLBP demonstrated higher regional mean lumbar BMD T scores (95% CI) than those without CLBP (0.9 [0.6-1.1] vs 0.3 [0.2-0.5], respectively; P<.001). After accounting for sex and body mass index, vertebral segments with rotational asymmetry (in non-LBP participants only) and vertebral segments with motion restriction had higher mean BMD T scores than vertebral segments with no asymmetry or motion restriction. Participants with CLBP had significantly higher lumbar BMD than participants without LBP. The presence of rotational asymmetry or motion restriction was associated with elevated BMD at the affected vertebrae.