The relationship between facet tropism and lumbar disc herniation in patients with low back pain

Introduction: Intervertebral disc herniation is a degenerative lumbar disease and a common pathology of skeletal system. Currently, most experts assume that facet tropism may affect lumbar degenerative diseases. However, the reports on relationship between facet tropism and lumbar disc herniation are inconsistent. Objective: To compare the relationship between facet tropism and lumbar disc herniation. Materials and Methods: In this cross-sectional study, patients with low back pain referring to Radiology Department of Poursina Hospital in 2017–2018 with lumbar disc herniation in only one intervertebral level (L3–L4, L4–L5 or L5–S1) were included. Using gradual sampling, patients were categorized into two case and control groups. Lumbar MRI was performed on all patients and the results were studied by only one professional radiologist. Studied variables were collected with a checklist and analyzed using SPSS software (version 21). Quantitative variables were compared using T-test and qualitative (categorical) variables were compared using Contingency Tables and Chi-Square test and/or Fisher’s Extract. P < 0.05 was identified statistically significant. Findings: Seventy-six patients with lumbar disc herniation were compared in terms of facet tropism presence. Investigating facet tropism in L4–L5 disc showed that percentage of facet tropism incidence in this level was 37% for patients with herniation (n = 10), while it was 10.2% in control group; the difference was statistically significant according to Chi-square test (P = 0.005). In L3-L4 level, percentage of facet tropism incidence in case and control groups were 43.8% (n = 7) and 18.3%, respectively. This 25% difference was statistically significant based on Fisher’s Exact test (P = 0.041). Findings for L5-S1 disc showed no significant relationship. Discussion: Given the inconsistent findings in previous studies on the relationship between facet tropism and lumbar disc herniation, the current study demonstrated the presence of this relationship. This findings can help experts prevent disc herniation to some extents through supportive and preventive measures.