Adult patients who were planned for lumbar facet joint medial branch nerve Radiofrequency ablation under fluoroscopic guidance because of facet joint-originated chronic lower back pain will be included in this study. Pain scores (Numerical Rating Scale and Oswestry Disability Index) will be recorded before and one month after the intervention. The morphology of the transverse processes and the facet joints (sizes and angles) will be evaluated using the computer tomography images that patients have in routine examination process. The possible relationship between the success rate of the procedure and the morphology of the transverse processes will be assessed by statistical analysis.

Our study will include patients who are examined at the Ondokuz Mayis University Algology Outpatient Clinic and diagnosed with chronic low back pain originating from the facet joints and deemed suitable for lumbar facet joint medial branch radiofrequency RF ablation (RFA) treatment. The study period will be between August 1, 2025, and June 30, 2026. Those who do not volunteer to participate in the study, those with significant anatomical deformities in the lumbar spine, those unable to answer the study questions, those with a history of lumbar vertebral surgery, and those who are or may be pregnant will be excluded.

Patients' gender, age, body mass index, and the duration of pain will be recorded. Patients' pain intensity will be assessed using the Numerical Rating Scale (NRS) and the Oswestry Disability Index (ODI). The NRS asks patients to rate their pain intensity between 0 and 10. 0 represents no pain, and 10 represents the highest pain they can imagine. Patients' NRS scores and ODI scores at rest and during activity will be recorded before and 1 month after the RFA procedure. A 40% or greater reduction in ODI score will be defined as "significant benefit from the procedure." The angles of the superior articular and transverse processes at the bilateral L1/2, L2/3, L3/4, L4/5, and L5/S1 levels, as well as the angles of the facet joint in the axial plane, will be calculated from Lumbar Spine Computed Tomography images taken during the diagnosis and treatment processes. No additional imaging will be required for this study; the data will be obtained from the patients' previously obtained lumbar spine CT images.

Patients will be divided into two groups for each level: "greater angle" and "lesser angle," based on the angles specified above. Post-procedure pain scores and the rate of significant benefit from the procedure will be compared. Patients will be evaluated one month after the procedure for pain scores and Oswestry Disability Index. Furthermore, a correlation will be investigated between the reduction in pain scores at each level and the specified angles. Statistical analyses of the study will be conducted using Statistical Package for Social Sciences (SPSS) version 26. Data obtained by counting will be expressed as numbers and percentages, and data obtained by measurement will be expressed as mean ± standard deviation. The Student t-test will be used for parameters showing normal distribution in comparisons of descriptive statistical methods and quantitative data, and the Mann-Whitney U test will be used for parameters not showing normal distribution. The chi-square test will be used for comparisons of qualitative data.

The relationship between changes in pain scores and the anatomical angles evaluated in the study will be assessed using the Pearson Correlation Test. A P value of less than 0.05 will be considered statistically significant.

This cross-sectional, observational study will not interfere with the patients' routine treatment protocols.

Sample Size and Statistical Methods: Statistical analyses of the study will be conducted using SPSS (Statistical Package for Social Sciences) version 26. Data obtained by counting will be expressed as numbers and percentages, and data obtained by measurement will be expressed as mean ± standard deviation. The Student t-test will be used for normally distributed parameters when comparing descriptive statistical methods and quantitative data, and the Mann-Whitney U test will be used for non-normally distributed parameters. The chi-square test will be used for comparisons of qualitative data. The relationship between changes in pain scores and the anatomical angles evaluated in the study will be assessed using the Pearson Correlation Test. A P value of less than 0.05 will be considered statistically significant.

Inclusion Criteria:

• Lumbar facet joint-originated lower back pain longer then 6 months.

Exclusion Criteria:

• Younger then 18
• Reluctance to participate in the study
• Severe anatomic deformation in lumbar vertebral region
• Presence or suspicion of pregnancy
• Inability to answer the questions of the study

Adult patients who have lumbar facet joint-originated lower back pain for longer than 6 months.

The authors of this study may share the participant data when there is a reasonable request.