Inclusion Criteria: 1. Patients with disc herniation or radiculitis who are over 18 years of age. 2. Patients with a history of chronic function-limiting low back pain and lower extremity pain for at least one months' duration. 3. Patients who are competent to understand the study and provide written informed consent and participate in outcome measurements. Exclusion Criteria: Patients have previous lumbar surgery with metal instrument. Initial MRI shows spinal stenosis or without disc herniation. Patients have unstable opioid use, uncontrolled psychiatric disorders, uncontrolled acute medical illness, any condition that could interfere with the interpretation of outcome assessments, pregnant or lactating women or allergy to local anesthetics or steroid. Patients who are unable to perform MRI or fMRI will also be excluded.