Comparison of the Efficacy of the Ultrasound With Fluoroscopy in Guidance of Lumbar Sympathetic Block

This study compares the efficacy of the ultrasound with fluoroscope in guidance of lumbar sympathetic block (LSB). The goals of the study are; 1) To show that US-guided LSB results in shorter performance time compared to fluoroscope-guided LSB, 2) To evaluate the efficacy and safety of US-guided LSB, and 3) To verify that US-guided LSB has similar success rates to fluoroscope-guided LSB. 50 patients who are supposed to undergo LSB due to sympathetically maintained pain, satisfy criteria of inclusion and exclusion, and voluntarily sign the informed consent will be enrolled.