An Examination of the Relationship Between Spinal-Pelvic Morphology and Lower Lumbar Facet Joint Remodeling in Individuals with Mild Degenerative Lumbar Spondylolisthesis

Abstract

Objective: To examine the relationship between spinal-pelvic morphology based on pelvic incidence angle and facet joint characteristics in the lower lumbar spine of patients with mild degenerative lumbar spondylolisthesis.

Methods: The study involved 167 patients with mild degenerative lumbar spondylolisthesis and patients with 100 nonlumbar spondylolisthesis. Morphologic parameters of L4-5 and L5-S1 facet joints and intervertebral discs were assessed using 3D CT images, including facet joint angle, pedicle-facet angle, asymmetry, and osteoarthritis. X-rays measured spondylolisthesis percentage, sacral slope, and lumbar lordosis. Both groups were categorized into 3 subtypes based on Spinal Deformity Study Group classification (Types I-III).

Results: Across both groups, as spinal-pelvic morphology shifted from Type I to III, facet joint angle (FJA) and pedicle-facet angle (PFA) were inversely related, the facet joint osteoarthritis worsened, and spondylolisthesis percentage increased. Facet asymmetry increased from Type I to II but decreased from Type II to III. Compared to controls, degenerative lumbar spondylolisthesis (DLS) patients exhibited more horizontal PFA, sagittal FJA, greater facet asymmetry, and more severe facet joint osteoarthritis. In DLS patients, FJA at L5 spondylolisthesis progressively aligned toward the coronal plane, while PFA became more horizontal. In contrast, the nonlumbar spondylolisthesis group showed sagittal FJA at L4 and vertical PFA.

Conclusions: Facet joint morphology is intricately tied to spinal-pelvic alignment, reflecting both post-DLS remodeling and variation across spinal-pelvic types. Facet joint changes significantly influence DLS progression and spinal balance. These findings emphasize the importance of joint remodeling in maintaining balance and optimizing surgical planning.

Keywords: Biomechanics; Degenerative lumbar spondylolisthesis; Lumbar facet joints; Morphological characteristics; Spinopelvic type.