For patients scheduled to undergo upper limb sympathetic nerve block due to chronic neuropathic pain in the upper limb lasting more than 3 months, the ultrasound-guided stellate ganglion block group (S group) and the fluoroscopy-guided thoracic sympathetic nerve block group (T) Patients are randomly assigned 1:1 to one of the groups, and the procedure is performed. To evaluate the effectiveness of sympathetic nerve blockade, temperature changes in both palms are measured twice, 20 minutes before and 20 minutes after the procedure, using an infrared thermographer. Other variables related to the procedure are surveyed by outpatient visit or telephone before the procedure, after the procedure, before returning home, and 1 week and 1 month after the procedure.

Patients aged 19 to 85 with upper limb pain are directly informed about the study, recruited, and enrolled at the Seoul National University Hospital Pain Center.

Before and after the procedure, continuous monitoring of electrocardiography, blood pressure, pulse rate, and oxygen saturation is carried out.

Before undergoing thoracic sympathetic ganglion block (TSGB) guided by fluoroscopy or ultrasound-guided stellate ganglion block (SGB), the temperature of both palms is measured using an infrared thermometer. Prior to the procedure, Doppler mode ultrasound equipment is used to measure blood flow velocity in the upper limb arteries (brachial artery).

In the case of ultrasound-guided stellate ganglion block, the patient is placed in a supine position, and the procedure is performed using ultrasound guidance to inject 5 mL of 1% mepivacaine at the level of C6. For fluoroscopy-guided thoracic sympathetic ganglion block, the patient is positioned prone, and 3 mL of 1% mepivacaine is injected at the level of T3. In both cases, the procedure is performed by a specialist with a rank of professor or higher who specializes in pain management.

After the procedure, the palm temperature is measured again 20 minutes later using an infrared thermometer.

Blood flow velocity in the upper limb arteries (brachial artery) is also measured 20 minutes post-procedure using Doppler mode ultrasound equipment.

Additionally, various procedure-related variables are assessed through outpatient visits or telephone surveys conducted before the procedure, at discharge, one week post-procedure, and four weeks post-procedure.

Inclusion Criteria:

• Adult patients with 19 - 85 years
• Patients with chronic upper extremity pain that lasts for more than 3 months
• Neuropathic pain conditions such as postherpetic neuralgia, complex regional pain syndrome, post laminectomy syndrome of cervical spine
• Patients judged to require sympathetic blockade by pain physician

Exclusion Criteria:

• Patient refusal
• Presence of upper limb vascular disorders
• History of previous thoracic sympathetic ganglion removal or neurolysis
• Abnormal findings in blood coagulation tests
• Systemic infection or local injection site infection
• Anatomical deformities at the injection site
• Allergic reactions to the injected medications
• Higher baseline hand temperature on the procedure side than the tympanic temperature (36.5°C) on pre-procedure thermography
• Other cases deemed inappropriate by the investigator