Complex regional pain syndrome (CRPS) is a clinical syndrome characterized by severe intractable and variable pain, dystrophy and dysfunction secondary to accidental injury, medical injury or systemic disease. It includes two typical sympathetic pain disorders, namely reflex sympathetic dystrophy and burning neuralgia, which are commonly seen after spinal cord injury and amputation. Clinical features 1. Pain: Most patients are induced by mechanical, thermal, mental, or emotional stimuli, and such pain includes spontaneous pain, nociceptive hypersensitivity and nociceptive hypersensitivity and other neurogenic pain. In some cases, 3 to 6 months or even longer after the injury, it can still 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. Myofascial hypertrophy may also lead to joint contracture and osteoporosis. Bone scan or x-ray may show osteoporosis. Diagnostic criteria ① A long or recent history of injury or disease. ②Persistent burning-like pain with neurogenic pain manifestations. ③There is vascular and sweating dysfunction, nutritional changes such as muscle atrophy, limb edema or dehydration, and hypersensitivity to cold and other stimuli. ④Diagnostic sympathetic nerve block test is mostly positive. Treatment Once diagnosed, methods to reduce pain should be sought as early as possible, and rehabilitation treatment should be actively carried out at the same time. 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 peptide, and it can also stimulate the thick fiber nerve at the pain site, change the sensory impulse to the central nervous system, and achieve the purpose of reducing pain. 3, drug treatment: ① antidepressants: commonly used are amitriptyline, promethazine, doxepin and other tris(tetra)cyclic antidepressants. ② Anti-epileptic anti-spasmodic drugs: representative drugs are carbamazepine, phenytoin sodium, sodium valproate, effective for nerve shock-like pain. The more widely used abroad is gabapentin, which can significantly relieve neuralgia caused by diabetes or herpes zoster. ③Non-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. The sympathetic nerve block performed clinically mainly works by blocking its mediated pain and dilating the blood vessels in its innervated area. 5.After anesthetic block by the authorities, if the pain symptoms do not improve or only temporarily improve, the use of nerve-destroying drugs, neurodestruction or sympathectomy should be considered. 6.When the above treatment is ineffective, analgesic pacemaker or subarachnoid analgesic pump implantation can be considered.