Our department recently treated a patient with a typical lower extremity complex painful regional syndrome. The patient developed pain and cold sensation in the left lower extremity 7 months ago after a sprain of the left ankle joint, and still felt cold to the bone marrow in thick pants in voltaic days. After various medications and physical therapy, spending more than 20,000 yuan without any improvement in symptoms. Fifteen minutes after surgery, the skin temperature of the left lower extremity increased by about 5°C, the color of the heel turned flushed, and the cold feeling and pain in the lower extremity were significantly relieved. Complex painful regional syndrome is a clinical syndrome characterized by severe intractable and variable pain, malnutrition and dysfunction that occurs secondary to accidental injury, medically induced injury or systemic disease. Lumbar sympathetic nerve chemical disruption is a minimally invasive intervention that uses medical alcohol to destroy part of the lumbar sympathetic nerve tissue, thereby blocking its nerve conduction function. Under the guidance of CT, a 0.7mm diameter needle is used to reach the sympathetic ganglion in the anterolateral part of L2 vertebrae, and a contrast agent is injected to show the exact location. This not only increases the blood flow to the arteries and veins of the lumbar region and improves the ischemia of the nerve roots, but also expands the blood vessels in the lower limbs that it innervates and establishes collateral circulation, which improves the overall blood circulation of the lower limbs, thus treating diseases caused by ischemia of the lumbar region and lower limbs. The procedure is effective, fast-acting and short-lived, with no adverse effects or sequelae, and can be used for daily life and work after surgery. Indications for chemical destruction of lumbar sympathetic nerve: 1. Pain-based diseases: discogenic lumbago; herpes zoster neuralgia; ischemic necrosis of femoral head, etc. 2. Lower limb vascular diseases and associated pain: thrombo-occlusive vasculitis, lower limb venous embolism, lower limb refractory ulcers, lower limb Raynaud’s disease, hyperhidrosis and limb cyanosis, etc. 3. Lower limb pain after trauma and surgery: phantom limb pain, burning pain, neuritis, lower limb edema, etc. after surgery and trauma.