Obesity measured by outer abdominal fat may cause facet joint arthritis at the lumbar spine

BACKGROUND AND OBJECTIVES There is a lack of studies on obesity measured by outer abdominal fat (OAF), which describes abdominal subcutaneous adipose tissue thickness with regard to spino-pelvic parameters. We investigated OAF and its physiologic values on computed tomography (CT) scans with regard to age, gender, facet joint (FJ) arthritis, FJ orientation, lumbar lordosis (LL) and pelvic incidence (PI). MATERIAL AND METHOD CT scans of 620 individuals, with a mean age of 42.5 years were reviewed. OAF, lumbar FJs, LL and PI were evaluated. RESULTS OAF showed a mean value of 19.7 millimeters (mm). It significantly increased with age until 70 years and decreased thereafter (p ⩽ 0.0001). There was no significant gender difference. OAF was significantly increased with FJ arthritis (p=0.01), but not with FJ orientation. OAF was not significantly associated with LL or PI.CONCLUSION: OAF on CT scans has a mean value of 19.7 millimeters. It is higher in the older age groups until 70 years. As a novelty finding, OAF significantly increases with higher degrees of FJ arthritis, but is not related to gender, FJ orientation, LL or PI. Differences in fat distribution may be found at other anatomic sites, such as visceral fat. Obese patients may benefit from weight loss by decreasing their FJ arthritis, which may potentially decrease associated back pain.