Initially the nerves (medial branch nerves) are numbed using a local anesthetic. These nerves are attached to the facet joints of the spine. Disease or injury of these joints can cause pain in the medial branch nerves. This pain may travel through the low back, buttocks and/or hips. A medial branch block can help your physician find the source of your pain. If this procedure provides adequate temporary relief, then a radiofrequency ablation may be performed. During this minimally invasive procedure, the physician uses heat from radio waves to treat painful facet joints in your back.