APP-based Precise Management System of Chronic Intractable Pain

Inclusion Criteria: * Have been clinically diagnosed with chronic, intractable pain for more than three months. * At enrollment, the average pain intensity is no least than 5 out of 10 cm on visual analogue scale. * At enrollment, the age is no younger than 18-year-old. * Ineffective or unsatisfactory conservative treatments, including but limited to: oral medication, nerve block, epidural corticosteroids, physical and psychological rehabilitation therapy, and chiropractic care. * Voluntary to take the trial and sign the informed consent. * Good compliance and ability to complete post-operative follow-ups. * Basic ability to read and use a mobile phone or having a caregiver who can. Exclusion Criteria: * Bleeding complications or coagulation disorders. * Mental or cognitive disorders leading to inability to complete implantation surgery or post-operative follow-up. * Issues with spinal cord or vertebrates that are not suitable for implantation surgery. * Systemic active infections or local infections around the surgery area. * Pregnancy, breast-feeding, plan to be pregnant or unwilling to use contraceptive methods. * Metastatic malignant tumors or untreated malignant tumors. * Life expectancy of less than one year. * Already provided with a medication pump and/or other implanted devices. * Need for therapy or examination that must not have an implanted pulse generator (IPG), such as magnetic resonance imaging (MRI) and thermo-therapy. * Heavily addicted to alcohol or drugs. * VAS improvement less than 50% or stimulation intolerance during the test period. * Unable to complete long-term online follow-ups because of hardware issues such as internet, mobile phones, and so on. * Unwilling to participate. * Other inappropriate situations determined by the investigators.