I. Common sympathetic nerve-related pain 1. Complex local pain syndrome (CRPS) contains two types of typical sympathetic pain disorders, namely reflex sympathetic dystrophy and burning neuralgia. The lesions are characterized by peripheral neurovascular lesions accompanied by abnormalities in central nervous system signaling. The waterfall-like release of inflammatory mediators and nociceptive factors from the damaged tissues stimulates the peripheral nerves, nerve roots, and central nervous system, triggering the reconfiguration of the pain reflecting system in the cerebrospinal cord and thalamus, ultimately leading to nociceptive hypersensitivity and abnormal pain. It is commonly seen in various post-surgical pain syndromes, pain caused by radiotherapy, nerve damage caused by viruses, infections, etc. Although the etiology and mechanism of these painful diseases are different, the clinical manifestations are mostly similar. 2. Visceral pain Pain originating from visceral organs is transmitted to the center through the vegetative nerves. It is mostly caused by tumors, ischemic or inflammatory lesions, etc. It is characterized by an indefinite location, a wide range of pain, and often associated with involvement pain. The pain caused by the wall layer of the chest, peritoneum and mesenteric and diaphragm is transmitted by the somatic nerve, so once the lesion invades, a more fixed and definite pain can appear. 3. Peripheral vascular painful diseases include pain caused by peripheral vascular contraction dysfunction, embolism, sclerosis and other lesions. Most of these diseases have sympathetic dysfunction, and can be diagnosed, prognosis and treatment by sympathetic block. For example, Raynaud’s disease, red scarring limb pain, hand and foot cyanosis, reticular cyanosis, arteriovenous embolism, vasculitis, retinopathy, etc. 4.Other indeterminate into the complaint syndrome, atypical facial pain, neuropathic pain, etc. How to determine the degree of sympathetic involvement Such as reflex sympathetic dystrophy (RSD), burning neuropathic pain (causalgia), etc., are caused by abnormal sympathetic hyperfunction, which is typical sympathetic nerve-related pain, so sympathetic block should have good efficacy. However, we often encounter cases in which the pain cannot be completely prevented even after a complete sympathetic block; there are even some patients whose pain is aggravated after sympathetic block. This phenomenon suggests that although some cases have exactly the same clinical symptoms, the response to sympathetic blockade varies because the pathogenesis is different. Therefore, it has been advocated that in such diseases, those that respond well to sympathetic blockade are called sympatheticallymaintainedpainSMP, and those that do not respond to sympathetic blockade are called sympatheticallyindependentpainSIP. And for those whose pain worsens after sympathetic blockade is called ABC syndrome (AngryBackfiringC-nociceptorsyndromeABC syndrome). Even in the same patient, at different stages of disease development, there can be manifestations of SMP, SIP, ABC syndrome, etc. Methods of vegetative nerve function examination. Sympathetic interventions 1. Common methods: SGB, thoracic sympathetic block, lumbar sympathetic block, ventral plexus block, odd ganglion block, intravenous local nerve block. Epidural block, subarachnoid block and local pain point block can also be used as appropriate. Recent studies have shown that neuromodulation techniques have a good modulating effect on sympathetic nerve function. Among them, neurostimulation therapy as the representative, increasingly shows the good therapeutic prospect of neuromodulation techniques for sympathetic nerve-related diseases. 2. Application principles Local anesthetic block. Especially if the pain is gradually reduced by repeated block, the block should be continued. When the pain symptoms do not improve or only temporarily improve after local anesthetic block, the use of neurodestructive drugs, nerve disruption surgery or sympathectomy by applying physical methods should be considered. When sympathetic nerve trunk and ganglion blocks are performed, the principle of using a single drug and local anesthetics should be emphasized. As in the case of SGB, which is widely used in clinical practice, a very complex formulation of anti-inflammatory and analgesic solution is often used for SGB. this is unnecessary and prone to increased complications, and is not in accordance with the therapeutic mechanism of SGB. Neuromodulation techniques. Transcutaneous electrical nerve stimulation, peripheral nerve stimulation, spinal cord electrical stimulation, deep brain stimulation, cortical stimulation, etc. Neurodestructive treatment. Commonly used neurodestructive drugs include anhydrous ethanol, phenol glycerol, etc. Commonly used physical nerve destruction methods include laser, radiofrequency, etc.