There are several places that anesthetics, steroids, or both can be injected to relieve low back pain. Facet-joint injections are given into the small joints linking the vertebrae together on the back of the spinal column. Epidural injections go into the membrane that surrounds the spinal cord. Local injections can be applied to other sites, including ligaments and trigger points.
The location of the injection depends on the kind of pain being treated. Facet-joint injections are often used when pain is coming from an arthritic or sprained facet joint. Epidural injections may help patients with pain that spreads from the back into the legs, primarily due to a herniated disc. Local injections help reduce muscle spasm and pain from a sore ligament. Your doctor can tell you which kind of injection may help you, based on the source of your pain.