Somatic dysfunction and its association with chronic low back pain, back-specific functioning, and general health: results from the OSTEOPATHIC Trial.

CONTEXT Somatic dysfunction is diagnosed by the presence of any of 4 TART criteria: tissue texture abnormality, asymmetry, restriction of motion, or tenderness. OBJECTIVE To measure the prevalence of somatic dysfunction in patients with chronic low back pain (LBP) and to study the associations of somatic dysfunction with LBP severity, back-specific functioning, and general health. DESIGN Cross-sectional study nested within a randomized controlled trial. SETTING University-based study in Dallas-Fort Worth, Texas. PATIENTS A total of 455 adult research patients with non-specific chronic LBP. MAIN STUDY MEASURES Somatic dysfunction in the lumbar, sacrum/pelvis, and pelvis/innominate regions, including key lesions representing severe somatic dysfunction. A 10-cm visual analog scale (VAS), the Roland-Morris Disability Questionnaire (RMDQ), and the Medical Outcomes Study Short Form-36 Health Survey (SF-36) were used to measure LBP severity, back-specific functioning, and general health, respectively. RESULTS Severe somatic dysfunction was most prevalent in the lumbar (225 [49%]), sacrum/pelvis (129 [28%]), and pelvis/innominate (48 [11%]) regions. Only 30 patients (7%) had no somatic dysfunction in the lumbar, sacrum/pelvis, or pelvis/innominate regions. There were 4 statistically significant pairwise correlations for severe somatic dysfunction: thoracic (T) 10-12 with ribs; T10-12 with lumbar; lumbar with sacrum/pelvis; and sacrum/pelvis with pelvis/innominate. Having a key lesion in the lumbar region (ρ=0.80) or sacrum/pelvis region (ρ=0.71) was strongly correlated with the overall number of key lesions. There were no consistent demographic or clinical predictors of somatic dysfunction. The presence (vs absence) of severe somatic dysfunction in the lumbar region was associated with greater LBP severity (median VAS score, 4.7 vs 3.8, respectively; P=.003) and greater back-specific disability (median RMDQ score, 6 vs 4, respectively; P=.01). The presence (vs absence) of severe somatic dysfunction in the sacrum/pelvis region was associated with greater back-specific disability (median RMDQ score, 6 vs 5, respectively; P=.02) and poorer general health (median SF-36 score, 62 vs 72, respectively; P=.002). An increasing number of key lesions was associated with back-specific disability (P=.009) and poorer general health (P=.02). CONCLUSION The present study demonstrates that somatic dysfunction, particularly in the lumbar and sacrum/pelvis regions, is common in patients with chronic LBP. Forthcoming extensions of the OSTEOPATHIC Trial will assess the efficacy of OMT according to baseline levels of somatic dysfunction.