Is There Any Association Between Orientation of the Lumbar Facet Joints and Increasing Age in White and Black Patients?

Background: Numerous studies have found an association between sagittally oriented facet joints and degenerative lumbar spondylolisthesis. Several studies have found sagittalization of lumbar facet joints with aging in various Asian patients. However, there is a paucity of evidence on the association between orientation of the lumbar facet joints and age in White and Black patients. If there are differences, this might be important because it may provide a clue for the difference in the prevalence of degenerative lumbar spondylolisthesis among races.

Question/purpose: Is there any association between orientation of the lumbar facet joints and increasing age in White females, Black females, White males, and Black males?

Methods: This is a retrospective study drawn from a large, longitudinally maintained database. We sought to include CT scans from patients aged 20 to 79 years who underwent abdominal and pelvic CT for trauma screening in the New York City area and whose race was classified as White or Black on an emergency department questionnaire between March 2019 and March 2020; we believed that period would provide a sufficient number of CT scans to achieve the desired sample size of 45 measurements at each facet level (after excluding those scans in which the angles could not be measured because of arthritic changes) for each of the two study groups. A total of 1343 patients were included (650 White patients [339 females and 311 males] and 693 Black patients [355 females, 338 males]). The facet joint orientation angle of both sides was measured at L1-L2, L2-L3, L3-L4, L4-L5, and L5-S1 in the axial planes on CT images, and a mean of both sides was taken as the facet joint orientation. The smaller this angle, the more sagittally oriented the facet joint. Associations between the angle and age were analyzed.

Results: Facet joint angles slightly increased with aging at L1-L2 in White females (R = 0.11; p < 0.05) and decreased slightly with aging at all levels in Black females (R = -0.18, -0.24, -0.13, -0.25, and -0.21 at the level of L1-L2, L2-L3, L3-4, L4-L5, and L5-S1, respectively; p < 0.05 for all). Facet joint angles increased slightly with aging at L1-L2 in White males (R = 0.14; p = 0.02) and decreased slightly with aging at L1-L2, L2-L3, L3-L4, and L4-L5 in Black males (R = -0.14, -0.17, -0.20, and -0.15, respectively; p < 0.05 for all). At L4-L5, the largest decreasing trend of facet joint angles with aging (R = -0.25; p < 0.01) was shown in Black females, and the mean facet joint angle was the smallest in Black females who were 70 years of age.

Conclusion: Lumbar facet joint angles slightly decreased with aging in Black females and males, whereas they did not in White females or males. At L4-L5, the largest decreasing trend of facet joint angles with aging was shown in Black females. Our results may help future authors to ascertain the reason for the high prevalence of degenerative spondylolisthesis at L4-L5 in Black females.

Level of evidence: Level III, prognostic study.