This retrospective observational study aims to evaluate the predictive value of systemic inflammatory markers in determining treatment response in patients with lumbar radicular pain treated with a combination of pulsed radiofrequency (PRF) and transforaminal epidural steroid injection (TFESI). Hematologic indices derived from routine blood tests-including neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), lymphocyte-to-monocyte ratio (LMR), platelet-to-neutrophil ratio (PNR), neutrophil-to-monocyte ratio (NMR), systemic immune-inflammation index (SII), systemic inflammation response index (SIRI), mean platelet volume (MPV), red cell distribution width-standard deviation (RDW-SD), and red cell distribution width-coefficient of variation (RDW-CV) and pain scores assessed using the Numeric Rating Scale (NRS), will be analyzed in relation to treatment success (defined as ≥50% NRS reduction at 4 weeks). Receiver operating characteristic (ROC) analysis will be used to determine optimal cutoff values for significant markers. The study aims to contribute to personalized pain management strategies by identifying accessible biomarkers that may predict treatment outcomes.

This retrospective, observational study aims to investigate whether systemic inflammatory markers can predict treatment response in patients with lumbar radicular pain who have undergone pulsed radiofrequency (PRF) therapy and transforaminal epidural steroid injection (TFESI) targeting the dorsal root ganglion (DRG).

Inflammatory parameters derived from the complete blood count-such as neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), lymphocyte-to-monocyte ratio (LMR), platelet-to-neutrophil ratio (PNR), neutrophil-to-monocyte ratio (NMR), systemic immune-inflammation index (SII = Platelet × Neutrophil / Lymphocyte), systemic inflammation response index (SIRI = Neutrophil × Monocyte / Lymphocyte), mean platelet volume (MPV), red cell distribution width-standard deviation (RDW-SD), and red cell distribution width-coefficient of variation (RDW-CV) and pain severity scores on the Numeric Rating Scale (NRS) will be assessed.

Patients aged 18 to 85 with clinically and radiologically confirmed lumbar radiculopathy, who received both PRF and TFESI in the same session and have pre-intervention laboratory data and 4-week post-intervention NRS scores, will be included. Exclusion criteria involve prior lumbar surgery, systemic inflammatory or hematological diseases, malignancy, active infection, recent steroid or immunosuppressive use, or incomplete data.

The primary outcome is treatment success, defined as a ≥50% reduction in NRS score at 4 weeks after the intervention. Patients will be grouped as "successful" or "failed" based on this criterion. Between-group comparisons will identify which markers significantly differ. For parameters with statistically significant differences, ROC curve analysis will be performed to determine sensitivity, specificity, and optimal cutoff points using the Youden index.

This study will use anonymized, retrospective data and poses no physical or psychological risk to participants. It will be conducted in accordance with the Declaration of Helsinki. The anticipated sample size is approximately 200 patients over a one-year period. Statistical analyses will be performed using IBM SPSS Statistics version 25.0. Descriptive statistics will summarize the data. The normality of continuous variables will be assessed using the Kolmogorov-Smirnov test. Independent samples t-test or Mann-Whitney U test will be used based on distribution, and categorical comparisons will be made with chi-square or Fisher's exact test. A p-value of <0.05 will be considered statistically significant.

The findings are expected to enhance clinical decision-making by identifying practical and inexpensive hematologic markers that could help predict treatment response, allowing for more personalized approaches to pain management.

Inclusion Criteria:

• Age between 18 and 85 years.
• Clinically and radiologically confirmed diagnosis of lumbar radiculopathy.
• Underwent pulsed radiofrequency (PRF) and transforaminal epidural steroid injection (TFESI) targeting the same dorsal root ganglion (DRG) in a single session.
• Availability of pre-intervention laboratory data, including: Complete blood count (CBC)
• Documented Numeric Rating Scale (NRS) scores before and 4 weeks after the intervention.
• Medical records complete for demographic, clinical, and laboratory variables.

Exclusion Criteria:

• History of prior lumbar spine surgery.
• Presence of systemic inflammatory, autoimmune, or hematological diseases.
• Diagnosis of malignancy.
• Active infection at the time of procedure.
• Use of systemic corticosteroids or immunosuppressive agents within the last 4 weeks.
• Incomplete clinical or laboratory data.
• Patients outside the age range (under 18 or over 85)

This study includes adult patients aged 18 to 85 years with clinically and radiologically confirmed lumbar radiculopathy who underwent pulsed radiofrequency (PRF) and transforaminal epidural steroid injection (TFESI) targeting the same dorsal root ganglion (DRG) in a single session. All participants had available pre-intervention laboratory data and Numeric Rating Scale (NRS) scores at the baseline and 4 weeks post-intervention. Patients with prior lumbar surgery, systemic inflammatory or hematological conditions, malignancy, active infection, recent steroid or immunosuppressive use, or incomplete records were excluded.