Lumbar facet joints have been implicated in the cause of chronic low back pain in 15% to 45% of patients, which was based upon their responses toward controlled, diagnostic blocks according to the criteria set by the International Association for the Study of Pain. Treatment effects for facet join pain in 3 types of intervention, including intraarticular injection, medial branch nerve block, and neurolysis using radiofrequency, have been reported. These treatment options have been implicated in refractory cases of facet joint pain who are not responsive to conservative management. Appropriate management methods for the facet joint pain are still in argument. Facet joint intra-articular (IA) injection are conventionally and preferably performed under fluoroscopy (FL) or computed tomography (CT)-guided. Both guidance modalities deliver significant radiation doses and require, at least in part, expensive equipment. However, an ultrasound (US)-guided approach can be safe and reliable without radiation exposures. Recently, many studies have demonstrated the reliability of ultrasound (US) guidance for different spinal injections. Ultrasound provides real-time monitoring, is a relatively inexpensive image guidance modality, does not produce ionizing radiation, and is broadly available.

We hypothesized that US-guided facet IA injection provides non-inferior analgesic efficacy and functional outcome as compared to conventional FL-guided injection without any risk of radiation exposure with added advantages of cost-effective, feasible, easily accessible, portable, and real time visualization of needle and surrounding structure.