To evaluate the safety and efficacy of ultrasound combined with CT-guided sympathetic ganglion block for refractory pain caused by sympathetic neuropathy of the lower extremities.

To evaluate the safety and efficacy of ultrasound combined with CT-guided sympathetic ganglion block for refractory pain caused by sympathetic neuropathy of the lower extremities. Patients with lumbar sympathetic block were enrolled and randomized to a conventional CT-guided group and an ultrasound-guided CT-guided group. By comparing the traditional CT guided and ultrasound combined with CT guided two programs, the radiation dose, block success rate, treatment time, etc. received by patients with lumbar sympathetic block were observed to understand whether ultrasound combined with CT guidance is a way to reduce radiation exposure. Under the premise of the dose, the method of blocking the success rate can still be guaranteed.

Inclusion Criteria:

1.18~80 years old; 2.Pain disorders requiring lumbar sympathetic block（Such as,Lower limb vascular disfunction,Diabetic polyneuropathy,Postherpetic neuralgia,Complex regional pain syndrome I and II,Cancer related neuropathic pain including Peripheral neuropathy caused by chemotherapy or other lower extremity sympathetic neuropathy）,conservative treatment for 3 months or longer can not be cured; 3.Numerical rating score≥4.

Exclusion Criteria:

1. Body mass index> 30 kg / m2;
2. History of internal fixation in posterior lumbar laminectomy or any serious anatomic variation, such as scoliosis and tumors;
3. History of lumbar sympathetic neurochemistry or thermal neurolysis;
4. Pregnancy;
5. The puncture site is infected;
6. Coagulation dysfunction;
7. Allergic to local anesthetic or contrast agent;
8. Cognitive impairment or inability to provide informed consent.