The purpose of this study is to investigate the potential analgesic effect of skin stretching during local anesthetic injection in patients with chronic lumbar pain and bilateral lower extremity radiculopathy undergoing selective transforaminal nerve block. This research is based on the hypothesis that mechanical skin stretching can reduce injection-related pain by facilitating the dispersion of the anesthetic agent and decreasing tissue resistance. By comparing the skin stretching technique with the conventional method of local anesthetic administration, this study aims to evaluate differences in pain perception, discomfort, and behavioral pain responses. The ultimate goal is to provide evidence for a simple, non-invasive, and effective intervention that can improve patient comfort and enhance the quality of clinical pain management.

Inclusion Criteria:

• Adults aged 19 years or older with chronic low back pain lasting for more than 3 months, accompanied by bilateral lower extremity radiculopathy, who require Selective Transforaminal Epidural Block (STEB).
• Patients with a Numerical Rating Scale (NRS) score of 5/10 or higher, with pain that affects daily life activities.

Exclusion Criteria:

• Patients whose pain is influenced by mechanisms other than radiculopathy, such as peripheral neuropathy or myelopathy.
• Patients with a history of lumbar surgery within the last 6 months, or spinal injection treatment within the last 3 months.
• Patients with a history of allergy to local anesthetics, steroids, or contrast agents, or those at increased bleeding risk due to anticoagulant use (INR > 1.2).
• Patients with localized infections, sepsis, uncontrolled diabetes, or hypertension.
• Patients who are unable to consent or cooperate with the study procedures (e.g., cognitive impairment, severe mental illness).