Study Design: This study was a case-control study examining the relationship between changes in Facet Joint Orientation and degenerative lumbar spondylolisthesis. Objective: The causal relationship between sagittal changes in the direction of the head-caudal facet joint and degenerative lumbar spondylolisthesis (DS) was investigated in this study. Summary of Background Info: Several radiologic studies have indicated a correlation between DS and an increased sagittal orientation of the facet joints. However, the orientation of the facet joints has only been measured on 1 axial cut of computed tomography scans and magnetic resonance imaging. Patients and Methods: Fifty-six patients with DS only at the L4/L5 level were assigned to the DS group, and 58 patients without DS were assigned to the control group. Two computed tomography scans were performed for the cephalad and caudad portions of the facet joint at L3/L4, L4/L5, and L5/S1 levels, respectively. Delta facet angle was defined as facet angle (cephalad)–facet angle (caudad). Results: Significant differences were observed in the joint angle of the L4/L5 head and tail processes between the DS group and the control group ( P <0.05). The direction of the L4/L5 slipped segment in the DS group was significantly inclined toward the sagittal position. Moreover, significant differences ( P <0.05) in the degree of joint degeneration in the L4/L5 head and tail processes were observed between the DS group and the control group, indicating more severe degeneration in the L4/L5 slip segment processes of the DS group. Conclusions: In the present study, we found that the changes in the sagittal direction of facet joints occur most probably due to lumbar degeneration remodeling rather than their underlying cause.
Zeng et al. (Tue,) studied this question.