Predictors of L4-L5 Degenerative Lumbar Spondylolisthesis: L4 Inclination Angle and Facet Joint Angle.

Objective: To evaluate the relationship between degenerative lumbar spondylolisthesis (DLS) and the L4 inclination angle (IA) and evaluate the risk factors of DLS.

Methods: Ninety patients with L4-L5 DLS and 90 with L4-L5 lumbar disc herniation or spinal stenosis (control group) were compared. Parameters including L4 IA, facet joint angle (FJA), cross-sectional area of paraspinal muscle, Pfirrmann grading of intervertebral disc, and degeneration grading of facet joint (FJ) were evaluated. The Student t tests and logistic regression analysis were used to analyze the risk factors of DLS.

Results: Statistical differences were found in L4 IA, cross-sectional area of multifidus muscle, FJA, and degeneration grading of FJ between 2 groups (P < 0.001, P = 0.07, P < 0.001, and P < 0.001, respectively). The logistic regression analysis demonstrated that greater L4 IA (β: -0.186, P < 0.001), more sagittal FJ (β: -0.117, P < 0.001), and more severe degeneration of FJ (β: -1.033, P < 0.001) were both significant predictors of DLS.

Conclusions: Patients with L4 IA greater than 11.15° and FJA greater than 60.19° are more likely to occur DLS.