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: OAF, lumbar FJs, LL and PI were evaluated on CT scans.
RESULTS: CT scans of 620 individuals with a mean age of 42.5 years were reviewed. 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, LL or PI.
CONCLUSION: OAF on CT scans seems to have a mean value of 19.7 mm. It is higher in the older age groups until 70 years and declines again afterward. As a novelty finding, OAF significantly increases with higher degrees of FJ arthritis, but is not related to gender or other spino-pelvic parameters such as 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, which may be worth further investigations.