The Prevalence of Facet Tropism and Its Correlation with Low Back Pain in Selected Community-Based Populations

Background: The incidence of facet tropism (FT) and its correlation with low back pain (LBP) have, to our knowledge, not yet been investigated among selected community-based populations who visited departments unrelated to LBP with their chief complaints unrelated to LBP. In this study, we aimed to evaluate the prevalence of FT among selected patients in whom LBP was not the chief complaint and the correlation between FT and LBP among these patients. Methods: Among patients who underwent computed tomography during 2014 for reasons unrelated to LBP, we enrolled 462 patients who satisfied the inclusion and exclusion criteria. The degree of tropism was defined as grade 0, 1, and 2 for FT, FT+, and FT++, respectively. LBP was evaluated using a modified version of the Nordic low back pain questionnaire. For additional evaluation of dynamic LBP, the question, "Did your pain go away when lying down still or standing up straight, and did it also intensify when you bend or stretch your back?," was included in the questionnaire. Results: The L4-5 intervertebral area was most frequently and severely affected by FT with an incidence rate of 46.3%, and severe FT was observed in 24.7% of the patients. FT increased with age at L2-3 and L5-S1 levels. FT at L2-3 level was correlated with LBP (p = 0.035) and dynamic LBP (p = 0.033). The FT grade at L2-3 level was correlated with dynamic LBP (p = 0.022) but not with LBP (p = 0.077). The relative risk of FT at L2-3 level was 1.614 for LBP and 1.724 for dynamic LBP. Conclusions: The prevalence of FT among community-based populations was 46.3% and its severe form was more frequently observed at L4-5 level (24.7%). LBP was correlated with FT at L2-3 level. The relative FT-associated risk of LBP was 1.6 at L2-3 level, and the relative L2-3 FT-associated risk of dynamic LBP was 1.724.