This study retrospectively analyzed medical records and imaging records (ultrasound images, fluoroscopy-guided images) of US-CSNRB and FL-CTFEB procedures performed at the Yangsan Pusan National University Hospital Pain Clinic outpatient department from May 1, 2019, to April 30, 2024. It compared the therapeutic effects (pain reduction), procedure-related indicators (comparison of contrast agent spread), safety (incidence of complications), and changes in analgesic usage.

The primary outcome of this study is the difference in pain chage (Visual Analogue Scale, VAS) between patients undergoing US-CSNRB and FL-CTFEB. The secondary outcomes are comparison of contrast agent spread and comparison of procedure-related complication rates.

The following information is retrospectively collected and observed for comparison based on the electronic medical records of selected patients.

1. Patient characteristics: Age, height, weight, gender, lesion segment (e.g., C6/C7), comorbidities
2. Procedure-related indicators:

1) Procedure method (US-CSNRB or FL-CTFEB) 2) Procedure site, procedure level, adverse events during the procedure 3) Contrast agent distribution pattern: Extent of contrast agent spread into the epidural space and into the nerve roots during the procedure 3. Treatment efficacy indicators: VAS (based on arm pain) at the first visit -baseline, the second visit - 1 month after procedure, the third visit - 2 month after procedure, and 4th visit - 3 months post-procedure; treatment success rate (VAS score reduction of 30% or more) 4. Safety indicators: Presence and type of procedure-related complications documented in medical records (e.g., intravascular injection, nerve injury, local anesthetic toxicity symptoms, transient motor paralysis, etc.).

Inclusion Criteria:

• Adult male and female patients aged 18 years or older.
• Patients diagnosed with cervical radiculopathy who underwent US-guided or FL-guided procedures.
• Patients with clearly documented pain scale (VAS) assessments in medical records at the following time points: 1st visit (before the procedure), 2nd visit, 3rd visit, and at least 3 months post-procedure.
• Patients who underwent procedures for lesions in a single or adjacent two segments.

Exclusion Criteria:

• Patients who underwent surgical treatment within one month after the procedure due to progressive neurological deficits.
• Patients with severe systemic diseases (e.g., cancer, severe immunosuppressive disorders) that may affect pain assessment.
• Patients with severe systemic diseases (e.g., cancer, severe immunosuppressive disorders) that may affect pain assessment.