Efficacy and Mechanism of Acupuncture for Chronic Sciatica Using fMRI

Inclusion Criteria: * adults 19 years of age or more and 70 years of age or less * clinical diagnosis of chronic sciatica (pain lasting 3 months or more) * 40mm or more of 100mm VAS for bothersomeness due to sciatica * volunteers through announcements and advertisements with written informed consent Exclusion Criteria: * spinal surgery within the past 6 months * diagnosis of specific severe diseases resulting in sciatica: malignant tumor, spinal infection, inflammatory sponlylitis * progressive neurological deficit or severe neurological signs * other chronic diseases which could disturb the effect of treatments and the results of the study: cardiovascular diseases, autoimmune diseases, renal diseases, diabetic neuropathy, dementia, epilepsy * inadequate or insafe for the treatment of acupuncture/ electroacupuncture: hemorrhagic diseases, medication of anticoagulant, serious diabetes mellitus vulnerable to infections, serious cardiovascular diseases/ pacemaker, metal materials interior of the body * currently or might be pregnant * severe mental illness * currently participating other clinical trials * experience of acupuncture or electroacupuncture treatment, or taking medicines which might affect the symptom of pain such as corticosteroids, narcotics, NSAIDs or considered to be inadequate by the investigators within the past week (But they could be included only after going through 2 weeks of wash out period.) * difficulty of writing informed consent * inadeguate or insafe for MRI scanning: claustrophobia, metal materials interor of the body * other inadequate subjects assessed by the study investigators