L5 Spondylolysis and Accelerating Osteoarthritic Changes in L5-S1 Facet Joints

Background: Spondylolysis is a defect in the pars interarticularis of the vertebra. The defect changes the biomechanical stresses and probably causes the degenerative process in the adjacent facet joints. Objectives: In this study, we aimed to assess the effect of L5 spondylolysis on the osteoarthritis process of adjacent L5-S1 facet joints. Methods: In this crosssectional cohort study, we assessed 157 cases with a history of low back pain who underwent lumbar computerized tomography scanning of two lower lumbar vertebrae for any reason. The patients with a medical history of vertebral fracture, previous surgery, or infection were excluded. The samples were placed into two groups; 1 (with L5 spondylolysis; 80 cases) and 2 (without spondylolysis; 77 cases). Then, their facet joints osteoarticular severity changes were scored and compared on imaging scans based on observing narrowing, sclerosis, osteophyte formation, and bone cyst. Results: The difference regarding the frequency of sex was not significant between the two groups. The prevalence rates of narrowing (P 0.001), sclerosis (P=0.032), and osteophyte (P=0.023) were significantly higher in group 1; however, bone cyst showed no significant difference (P=0.365). Data analysis by logistic regression showed that the aging process was more implicated than spondylolysis in increasing the prevalence of arthritic changes, but bone cysts were not associated with degenerative changes (P=0.216). Conclusion: Facet joint degenerative changes (including joint space narrowing, osteophyte, subchondral sclerosis, and cyst) in cases with L5 spondylolysis were not significantly different from those without it. These changes were more affected by the aging process than the spondylolysis itself.