Association between facet joint orientation/tropism and lumbar intervertebral disc degeneration.

Background: The aim of this study was to understand how facet joint orientation (FJO) and facet joint tropism (FJT) affected severe intervertebral disc degeneration (IVDD) process at lower lumbar levels in patients with LBP.Methods: This study is a cross-sectional analysis of a retrospective database. Patients were evaluated in terms of IVDD, FJO, and FJT at all lumbar levels on magnetic resonance imaging.Results: In this study (n: 123) facet joints were aligned more coronal in men than in women at upper lumbar levels. Men had less FJT compared to women, significantly at L2-L3 and L3-L4 levels. Severe IVDD at L4-L5 was associated with more coronal aligned L1-L2 (29.0 ± 2.5° vs. 23.3 ± 2.3°, p = 0.006) and misaligned L5-S1 (8.3 ± 1.9° vs. 4.5 ± 1.7°, p = 0.008). Besides, severe IVDD at L3-L4 was associated with more coronal aligned L4-L5 (49.1 ± 3.2° vs. 41.4 ± 2.8°, p = 0.014).Conclusion: There is a close association between FJO/FJT with lumbar IVDD. Facet joint orientation and FJT do not affect the disc at only the corresponding level; the lumbar spine should be evaluated as a whole.