Gabapentin Versus Transdermal Fentanyl Matrix for Chronic Neuropathic Pain

Inclusion Criteria: * patients are 20 years of age or older * patients had chronic pain for more than 3 months and average pain score for last 3 days is not less than 4 (NRS) * neuropathic pain caused by the spinal stenosis (radiating pain, motor or sensory change * positive MRI finding or radiculopathy was confirmed by the EMG/NCS or not less than 12 points in the S-LANSS score assessment * patients who can make out the questionnaire * patients have agreed with the informed consent Exclusion Criteria: * patients who have experience with gabapentin, pregabalin, fentanyl matrix, long-acting strong opioid (CR oxycodone, SR morphine) * patients who have other causes of neuropathy such as hypothyroidism, Vit B12 deficiency, connective tissue disease, etc. * patients who have other disease which causes more pain compared with neuropathic pain * patients with a history of drug or alcohol abuse * patients who are pregnant or have the possibility of pregnancy * patients who are unable to use a transdermal system due to skin disease * patients with a serious mental disease * patients with a history of hypersensitivity to opioid analgesics * patients with a chronic pulmonary disease or respiratory depression * patients combined with industrial accidents or traffic accidents * at investigator's discretion, any condition where a subject cannot take part in the clinical study on the ground of warning, cautions, and prohibition in study investigator's brochure