Complex localized pain syndrome (CRPS) refers to a clinical syndrome characterized by severe intractable and variable pain, malnutrition and dysfunction secondary to an accidental injury, medically induced injury or systemic disease. It contains two types of typical sympathetic pain disorders, namely reflex sympathetic dystrophy and burning neuralgia. I. Clinical features of CRPS 1. Pain: Most patients are induced by mechanical, thermal, mental and emotional stimuli, and such pain includes spontaneous pain, nociceptive hypersensitivity and nociceptive hypersensitivity and other neurogenic pain. In some cases, 3-6 months or even longer after the injury, still can show persistent pain, and spread to the surrounding area. 2, nutritional disorders: in the injury site and its surrounding tissues, often accompanied by vasomotor nerve dysfunction, swelling. Sometimes, although the swelling is not obvious, but often complains of a swollen feeling. The skin begins to sweat and mostly appears moist and flushed. The skin temperature may be variable high or low, with a tendency to decrease in the later stages, showing ischemic changes. With the progressive development of the disease, the growth rate of hair and nails changes from faster to slower, and the skin gradually becomes thin and the nails curl and lose their luster. 3.Motor function: Grip strength and fine-motor function can be reduced in the early stage. As the range of motion decreases, the joints become stiff due to muscle wasting atrophy. After 6 months of the disease, the skin becomes thin and shiny due to atrophy of the subcutaneous tissue, and the sweating of the affected skin increases or decreases. If the myofascial hypertrophy, it may also lead to joint contracture and osteoporosis. x-ray examination may show osteoporosis. Diagnostic criteria for CRPS 1. Longer or recent history of injury or disease. 2.Persistent burning-like pain with neurogenic pain manifestations. 3, there is vascular and sweating dysfunction, nutritional changes such as muscle atrophy, limb edema or dehydration, and hypersensitivity to cold and other stimuli. 4. The diagnostic sympathetic block test is mostly positive. Third, once CRPS treatment is diagnosed, methods to reduce pain should be sought as early as possible, while actively carrying out rehabilitation treatment. 1.Preventive treatment: perfect treatment of trauma and adequate analgesia in the early stage of injury is very important. That is, perfect control of pain in the acute phase, to stop its development toward chronicity, while combined with psychiatric treatment, it is generally believed that a better outcome can be achieved. 2.Transcutaneous electrical stimulation (TENS): Transcutaneous electrical stimulation is analgesic by activating endogenous opioid peptides, and it can also stimulate the thick fiber nerves at the pain site, change the sensory impulses to the central nervous system, and achieve the purpose of pain relief. (1) Antidepressants: commonly used are amytriptyline, promethazine, doxepin, meprotiline and other tri(tetra)cyclic antidepressants. (2) antispasmodics: representative drugs are carbamazepine, phenytoin sodium, sodium valproate, effective for nerve shock-like pain. More widely used abroad is gabapentin, which can significantly relieve neuralgia caused by diabetes or herpes zoster. (3) Non-steroidal anti-inflammatory and analgesic drugs, neurotoxin, prostaglandin preparations, hormones, morphine-like drugs, etc. (4) Nerve block treatment: sympathetic nerve block is the main treatment. Commonly used nerve blocks are: SGB, thoracic sympathetic block, lumbar sympathetic block, intravenous local nerve block, epidural block, subarachnoid block. Sympathetic nerve blocks performed clinically mainly function by blocking the pain mediated by them and dilating the blood vessels in their innervated areas. 5.Neurodestruction or sympathectomy: If the pain symptoms do not improve or only temporarily improve after anesthetic block by the authorities, nerve destructive drugs should be considered and nerve destructive surgery or sympathectomy should be performed. 6. Analgesic pacemaker or subarachnoid analgesic pump implantation: If the above treatments are ineffective, analgesic pacemaker or subarachnoid analgesic pump implantation can be considered. 7.Psychotherapy.