Ultrasongraphy Versus Fluoroscopy in Lumber Sympathetic Block in Chronic Lower Limb Ischemia

LSGBs will be performed at the lower third of the L2 or the upper third of the L3 vertebra without any premedication. The targeted lumbar vertebra will be identified with an anteroposterior (AP) fluoroscopic imaging in the FL group or with an US longitudinal tracing approach from the caudad to cephalad direction in the US group. The skin entry point will be infiltrated with 1% lidocaine. Then, a curved 21 G, 15-cm Chiba needle will be advanced toward the target using the posterolateral approach in both groups. Each patient will undergo LSGBs according to the allocated group.