Association of low back pain, somatic dysfunction, and lumbar bone mineral density: reproducibility of findings

Somatic dysfunction as diagnosed by palpation should be associated with an objective measure. Bone mineral density (BMD) has been shown to be elevated in lumbar vertebrae with somatic dysfunction and in the lumbar region of individuals with chronic low back pain (LBP).

To investigate the association of lumbar somatic dysfunction and BMD T-score variability in participants with chronic LBP and without LBP (non-LBP) and to determine the reproducibility of previously published results.

Two examiners, blinded to symptom history, evaluated participants for tissue texture abnormalities, rotational asymmetry, anterior motion restriction, and tenderness at vertebral levels L1 to L4. Participants also underwent dual-energy x-ray absorptiometry of vertebral levels L1 to L4 for the assessment of BMD T scores. Generalized linear models were used to compare the chronic LBP and non-LBP groups on the presence and severity of somatic dysfunction and to test whether group and the presence and severity of somatic dysfunction were related to BMD T scores.

Forty-three chronic LBP (54%) and 36 non-LBP participants (46%) completed the study. Although the presence of somatic dysfunction in the 2 groups was not significantly different, the presence of tenderness was significantly more common in the chronic LBP group (P<.001), as was the severity for tissue texture abnormalities (P=.03), motion restriction (P=.04), and tenderness (P<.001). Of the 316 vertebrae assessed, 31 (10%, all in the chronic LBP group) had moderate/severe tenderness. The vertebral somatic dysfunction burden score, the total somatic dysfunction burden score, the vertebral somatic dysfunction severity score, and the total somatic dysfunction severity score were higher in the chronic LBP group (all P<.001). The vertebral BMD T score was significantly higher for vertebrae demonstrating moderate/severe rotational asymmetry compared with those demonstrating mild or no rotational asymmetry (P=.01) and for vertebrae demonstrating moderate/severe tenderness compared with those demonstrating no tenderness (P=.04).

Study results suggest that somatic dysfunction was more significant in chronic LBP participants. Although the correlation between the presence of somatic dysfunction and segmental BMD T scores was not reproduced, BMD T scores were higher for vertebrae demonstrating moderate/severe rotational asymmetry and tenderness.