An epidural steroid injection (ESI) is a common way to treat inflammation associated with back pain, as well as related pain in the neck, legs, or arms. Spinal nerves may become inflamed due to narrowing of the passages where nerves travel as they pass down or out of the spine. An epidural procedure delivers powerful anti-inflammatory medicine directly into the space outside the spinal sac of fluid around the spinal cord. This area is called the epidural space. An ESI is not the same as epidural anesthesia given just before childbirth or certain types of surgery.
There are three common methods for delivering epidural steroids: interlaminar, caudal, and transforaminal approaches. All three approaches, performed on an outpatient basis, entail placing a thin needle into position using fluoroscopic (X-ray) guidance.
The steroid (cortisone) will usually begin working within 1-3 days, but in some cases it can take up to a week to feel the benefits. Although steroids do not change the underlying condition, they can break the cycle of pain and inflammation, allowing the body to compensate for the condition. In this way, the injections can provide benefits that outlast the effects of the steroid itself. Typically, epidural injections are given by anesthesiologists, physiatrists, or interventional radiologists with special training.
Most doctors limit patients to two or three injections per year, as having injections too often may weaken spinal bones or nearby muscles. Receiving higher doses of the steroids in these injections may cause similar problems. Epidural steroid injections have been performed for many decades, and are generally considered as a very safe and effective treatment for back and leg pain or neck and arm pain. Serious complications are rare.