Association of Subcutaneous Fat Index, Paraspinal Muscle Characteristics, and Facet Morphology With Lumbar Facet Joint Degeneration

This prospective observational study aims to investigate the association between subcutaneous fat index, paraspinal muscle characteristics, facet morphology, and lumbar facet joint degeneration in adults with chronic low back pain. The study will use lumbar magnetic resonance imaging (MRI) obtained as part of routine clinical care. The study will evaluate whether subcutaneous fat index is associated with moderate-to-severe lumbar facet joint degeneration and will also examine the relationships of disc degeneration, facet morphology, paraspinal muscle characteristics, and pain severity with facet joint degeneration.

Inclusion Criteria: \- Inclusion Criteria: 1. Age 18-75 years. 2. Low back pain lasting for at least 3 months. 3. Evaluation at the Algology outpatient clinic. 4. Lumbar MRI has been clinically indicated as part of routine patient management independently of the study. 5. Lumbar MRI images including sagittal T1-weighted, sagittal T2-weighted, and axial T2-weighted images covering the L1-L2 through L5-S1 levels. 6. Height and body weight can be measured. 7. Low back pain severity can be assessed using the Numeric Rating Scale (NRS). 8. Sufficient cognitive and linguistic capacity to complete the Oswestry Disability Index. 9. Ability to understand the study and provide informed consent. 10. Written informed consent to participate in the study. Exclusion Criteria: 1. Previous lumbar spine surgery or lumbar fusion. 2. Acute vertebral fracture or significant lumbar trauma. 3. Spinal malignancy or vertebral metastasis. 4. Spondylodiscitis or other spinal infections. 5. Inflammatory spondyloarthritis. 6. Advanced lumbar scoliosis. 7. Severe congenital lumbar vertebral anomaly. 8. Anatomic variation preventing reliable identification of vertebral levels. 9. Pregnancy. 10. Inability to complete the MRI examination. 11. MRI images inadequate for assessment of subcutaneous fat, intervertebral discs, facet joints, or paraspinal muscles. 12. Missing clinical data or required outcome measures. 13. Failure to provide written informed consent. Exclusion Criteria: \-