Electroacupuncture as a Complement to Usual Care for Patients With Non-acute Pain After Back Surgery

Inclusion Criteria: * Patients whose low back pain persisted or recurred after back surgery with or without leg pain. * Patients whose pain has been persisted at least 3 weeks recently and who are necessary to care intermittent medical treatments (eg. medication, injection, physio therapy). * Patients with pain, defined as an Visual Analogue Scale (VAS) value ≥ 50mm. * Patients who are 19 - 70 years of age. * Patients who agreed to voluntarily participate in this study and signed informed consent. Exclusion Criteria: * Patients who have been diagnosed with a serious disease that can cause low back pain (e.g., cancer, vertebral fracture, spinal infection, inflammatory spondylitis, cauda equine compression, or other disqualifying conditions). * Patients with progressive neurological deficit or severe neurological symptoms. * Patients whose pain causes are not resulted from spine or resulted from soft tissue diseases(e.g., cancer, fibromyalgia, rheumatoid arthritis, gout). * Patients with a chronic disease that could influences the effects of the treatment or the analysis of treatment results (e.g., cardiovascular disease, diabetic neuropathy, fibromyalgia, rheumatoid arthritis, dementia, epilepsy, or other disqualifying conditions). * Patients for whom acupuncture would be inappropriate or unsafe (e.g., hemorrhagic disease, clotting disorders, a history of receiving anticoagulant therapy, severe diabetes with a risk of infection, severe cardiovascular disease, or other disqualifying conditions) * Patients who are currently pregnant or planning the pregnancy. * Patients with psychiatric diseases. * Patients who are participating in other clinical trial. * Patients who are unable to sign informed consent. * Patients who are judged to be inappropriate for the clinical study by the researchers, such as inability to read and write Korean.