In 1965, Melzack and Wall proposed the doctrine of gate control of pain, and in 1967, C. Norman Shealy et al. treated six patients by removing the laminae under general anesthesia and implanting electrodes into the subarachnoid space, all of whom had pain relief or disappearance. After 1971, electrodes were implanted in the epidural space with the same pain-relieving effect and reduced the incidence of serious complications. In the past 30 years, with the continuous improvement of SCS implantation equipment, in-depth research on the pathophysiology, indications, expected efficacy and possible complications of this technique, the success rate and long-term efficacy of SCS have been improving, and it has become an important analgesic technique in the field of clinical pain today. The analgesic mechanism of SCS is currently recognized by the gate control theory published by Melzack and Wall in 1965, which suggests that the segmentally modulated neural network consists of primary afferent A and C fibers, dorsal horn projection neurons (T cells) and inhibitory interneurons (SG cells) in the glial region, with SG neurons playing a key gating role. β afferents excite SG cells, and Aδ and C afferents inhibit SG cells. Thus, electrical stimulation of Aβ fibers in the posterior column of the spinal cord retrogradely inhibits the reception of nociceptive information from the fine fibers of the stimulated spinal cord segments, reducing or blocking the transmission of injurious information to the center and providing pain relief. In addition, SCS has been observed to induce vasodilatory-like phenomena in both animal models of ischemic disease and human trials, so it is speculated that it may be related to the activation of central inhibitory mechanisms affecting sympathetic efferent nerves by SCS. These vasodilatory responses may be secondary to the effects of SCS following pain relief, or they may be secondary to the release of vasodilatory substances by this stimulation, such as vasoactive peptides, substance P, or calcitonin gene-related peptides. There are many other theories about the mechanism of action of spinal cord stimulation, including stimulation of the upward impulses of the posterior spinal cord to produce disturbing effects in the thalamus and cortex; activation of the higher central downward inhibitory pathways; and involvement of endogenous analgesic substances. Second, the selection of indications SCS is mainly used for the treatment of chronic pain, the indications include two major categories: neuropathic pain and pain caused by ischemic diseases. Neuropathic pain includes: peripheral nerve injury pain, low back surgery syndrome, chronic postherpetic neuralgia, complex local pain syndrome, etc.; ischemic diseases include: intractable angina, peripheral artery obstructive disease, Raynaud’s disease, etc. Neuralgia caused by peripheral nerve injury is the main important indication of SCS, with the most satisfactory analgesic effect and the longest duration of efficacy. These pains can be spontaneous or stimulus-induced, often secondary to trauma, surgery, nerve compression, inflammation, and metabolic disorders (polyneuropathy), among others. The results of large sample studies show that, with proper indications, SCS can provide approximately 50% or more pain relief in patients with neuropathic pain, significantly reduce the dosage of other analgesic drugs in 60-70% of patients, and improve quality of life and body function. In the United States, Failed back syndrome (FBS) is another major indication for SCS, accounting for more than half of all SCS procedures. A comprehensive survey showed that SCS treatment of FBS can provide more than 50% pain relief. However, the efficacy of SCS for FBS varies relatively widely, and it has been suggested that this may be related to the better efficacy of SCS for neuropathic pain and poorer results for the residual pain of some of its postoperative injuries. SCS provides relief for both type I complex regional pain syndromes (CRPS, formerly known as reflex sympathetic dystrophy, RSD) and type II complex local pain syndromes. Studies have shown that SCS relieves CRPS symptoms significantly better than patients who administer physical therapy alone. In Europe, SCS has been used mainly for the treatment of ischemic diseases, and the treatment of angina pectoris has been the focus of research on SCS since the early 1970s, with many reports in the literature each year. research on the economic and social benefits of SCS treatment, the impact on morbidity and mortality, and the mechanism of action has made great progress since 1987. The short-term efficacy is very good, and the efficiency often reaches 100%. The number of chest pain episodes, the degree of pain, the intake of nitroglycerin, and the degree of ST-segment reduction of ECG are significantly reduced, the exercise tolerance and exercise end time of exercise test are increased, the cardiac function is improved, and the quality of life is improved. Cook first treated vaso-obstructive ischemic ulcers of the lower extremities with SCS in 1976, but the results were poor. 1981 saw success with Niglio, with patients whose ulcers healed and pain disappeared. The benefits of SCS in the treatment of peripheral vascular disease are: (1) relief of pain, improvement of mobility of the affected limb, and improvement of quality of life; (2) improvement of The benefits of SCS treatment for peripheral vascular disease are: (1) relief of pain, improvement of mobility of the affected limb, and improvement of quality of life; (2) improvement of blood circulation in the affected limb and improvement of limb survival rate; (3) reduction of medical costs. It has also been reported that although SCS can significantly reduce pain, it does not reduce the rate of amputation. Screening test The first test stimulation is performed. The patient is placed in the prone position, and the epidural placement of electrodes is performed under local anesthesia. the key to successful SCS testing is to accurately implant the stimulating electrode into the corresponding spinal cord stage of pain, and to find the location of the electrode where the patient complains of abnormal sensation throughout the pain area. The fixed electrodes were then connected to an extracorporeal stimulator for temporary testing. The pain is assessed by visual analogue scale (VAS). If the pain relief is more than 50%, the quality of life is significantly improved and the dosage of analgesic drugs is significantly reduced, the test is successful and permanent implantation of the neurostimulation system can be performed. 2. Specific steps The patient is usually placed in the prone position, and the Tuohy needle is punctured from the marked vertebral space. The resistance disappearance method and X-ray are applied to confirm that the puncture needle enters the epidural space. Some patients with repeated back surgery have adhesions in the epidural space, and disc surgical electrodes can be implanted through laminectomy. After successful placement of the electrode, the end of the electrode is connected to the extracorporeal temporary extension lead and extracorporeal stimulator for testing to find the electrode location where the patient complains of abnormal sensation throughout the pain area, i.e., the tingling sensation produced by stimulation can completely or basically cover the range of the patient’s complaint of pain. After successful testing, the temporary electrode is fixed, and after 4-7 days of continuous extracorporeal testing, the pain level is significantly relieved (VAS score is reduced by more than 50%) and the quality of life is significantly improved, the implantation of the whole SCS system can be considered. IV. Complications 1. Bleeding and hematoma Epidural hematoma is quite rare yet a serious problem, and patients with coagulation abnormalities and those undergoing anticoagulation therapy must be excluded before surgery. Implantation site hematoma or seroma is likely to occur at the stimulator implantation site. Complications are mostly benign and absorption can be accelerated with the use of a lap band. Puncture and aspiration are generally not recommended unless there is a large collection of fluid. 2. Local infection The opportunity for infection is generally uncommon with permanent placement. During the test period because the epidural is in the open state, it should be operated according to strict asepsis, and antimicrobial agent should be applied for one week after the operation; once the stimulator implantation site or epidural abscess occurs, the implant should be taken away without any melancholy. 3, electrode displacement, wire fracture Electrode implantation early (within a few days) should avoid strenuous physical activities, such as neck, trunk transition flexion and extension and gyration; should try to choose the paracentral method for epidural puncture, to prevent the narrow spinal gap damage electrodes. 4. Foreign body sensation and pain at the site of stimulator insertion Most patients will have foreign body sensation in the early stage of implantation, and those with severe degree can be treated symptomatically with sedative drugs. A very small number of patients may experience wandering of the implanted stimulator and need to be refixed. 5. Other cerebrospinal fluid leakage, allergy, etc.