【Introduction】

The facet joints constitute a joint complex with the intervertebral discs and contribute to load distribution and control of excessive rotation. In most cases, degeneration of the lumbar spine occurs in the discs before the facet joints at the same spinal level, however, in a few cases, the facet joints degeneration (FJD) precedes the disc degeneration (DD) (FJD > DD). The purpose of this study was to investigate the characteristics of individuals with FJD > DD and their association with low back pain (LBP) using epidemiological data.

【Methods】

This was a community-based cross-sectional study. The subjects were 437 community residents (142 males and 295 females, mean age 65.0 years) who underwent lumbar spine MRI. We evaluated the left and right FJD from L1-L2 to L5-S using the Weishaupt classification (4 grades from 0-3). DD was measured by the Schneiderman classification (4 grades from 0-3). FJD > DD was defined as Weishaupt grade ≥ 2 in either the left or right facet joint and a Schneiderman grade = 0 in the disc at same spine level. Furthermore, subjects underwent blood and urine sampling, blood pressure measurement to assess for hypertension, diabetes, hepatic and renal dysfunction. Arteriosclerosis was assessed by cardio-ankle vascular index (CAVI) and osteoarthritis (OA) of the hip and knee joints were evaluated by the ARA classification (Altman 1986, 1991). LBP was assessed with a self-administered questionnaire and defined as pain requiring treatment lasting at least 1 month. We compared age, gender, BMI, prevalence of comorbidities and LBP between FJD>DD (+) and (-) groups. Statistical analysis was performed using the chi-square test, Mann-Whitney U test, and multiple logistic regression analysis, with a p-value of <5% considered statistically significant.

【Results】

A total of 219 subjects were enrolled, excluding those with compression fractures, scoliosis or degenerative spondylolisthesis. There were 16 (7.3%) subjects in the FJD>DD (+) group and 203 (92.7%) in the (-) group. There were statistically significant differences in only age (57.5±12.0 in FJD>DD (+) group vs. 65.5±109 in (-) group, p=0.004). On the other hand, there were no significant differences in gender (female/male 0.60 vs. 0.42, p=0.32), BMI (23.2±3.6 vs 23.3±3.2, p=0.68), hypertension (31.3% vs 56.2%, p=0.05), diabetes (0.0% vs 4.4% p=0.39), abnormal hepatic(37.5% vs 34.5% p=0.81) and renal function (18.8% vs 41.4% p=0.08), dyslipidemia (16.7% vs 32.5%, p=0.25), arteriosclerosis (16.7% vs 32.5%, p=0.25), knee (12.5% vs 32.6%, p=0.09) and hip OA (0.0% vs 6.9%, p=0.28) , LBP (18.8% vs 11.3%, p=0.38). Finally, multiple logistic regression analysis adjusted for age, gender, and BMI showed no significant differences between FJD > DD and LBP (OR=1.61, 95%CI: 0.39-6.65, p=0.51).

【Discussion】

In the present study, FJD > DD was more common in younger age groups, but there was no association with gender, BMI, or comorbidities including lower extremity OA. In addition, FJD>DD was not associated with LBP. Further studies with longitudinal data are needed to validate these results.