Abstract
BACKGROUND: Emerging evidence suggests that facet joint degeneration, disc pathology, and paraspinal muscle atrophy form a degenerative triad in young adults with lumbar disc herniation (LDH). However, the exact relationship remains unknown. This study aimed quantitatively to investigate their interrelationships through magnetic resonance imaging (MRI) morphometry. METHODS: Axial T2-weighted MRI served as the assessment tool in this retrospective study enrolling 60 young patients (33 disc bulging and 27 disc herniation). Measurements obtained at the responsible segment level included: lumbar curvature (Cobb angle), Pfirrmann score, intervertebral space height, facet joint angle, mean width of the multifidus pure muscle cross-sectional area (PMCSA), and multifidus fatty infiltration grade. Parameters were statistically compared between the bulging and herniation groups. Subsequently, multivariate logistic regression assessed the correlation between LDH severity and the MRI parameters. RESULTS: Intergroup analysis revealed statistically significant differences in age, sex distribution, treatment modality, Cobb angle, anterior/middle disc height, bilateral facet joint angles, and multifidus PMCSA (P < 0.05). Multivariate logistic regression demonstrated that facet tropism, Pfirrmann grade, and multifidus fatty infiltration grade were independently associated with LDH severity (P < 0.05). CONCLUSIONS: Facet tropism, intervertebral disc degeneration (quantified by Pfirrmann grade), and multifidus fatty infiltration represent established risk factors for LDH and likely contribute to its pathological cascade.