An epidural steroid injection is done to help relieve the symptoms of nerve irritation or inflammation. The irritation or inflammation can occur for a number of reasons including bulging or herniated discs, arthritis and bone spurs that form in the back. Depending upon the nerve, or nerves, involved, patients may develop pain and/or other symptoms in different parts of the body. This could include numbness, tingling, and weakness. Irritation of the nerves in the neck may cause pain in the neck, shoulder and arm. Irritation of the nerves in the upper back may cause complaints in the back, sides, chest or abdomen. In the lower back, irritation or inflammation of the nerves can cause low back pain, buttock or leg pain.
The nerves in the spine are covered by a thin membrane known as the dura. There is a space between the dura and the spinal canal called the epidural space. In an epidural spinal injection, the steroid medication is injected into this space.
Epidural steroid injections are most commonly performed as an outpatient procedure. Sometimes, though not always, an IV is started if medication for relaxation is to be administered. Patients are placed face down on a special x-ray table and the skin at the injection site is sterilely prepped. Numbing medication is then used to anesthetize the skin and tissue deep to the skin to make the procedure more comfortable. An x-ray machine called a fluoroscope is used to monitor placement of the epidural needle as well as where the medicine is being delivered. The procedure itself is relatively quick, taking approximately 20 minutes. Patients are monitored for a short time before being discharged home. On the day of the injection, patients are instructed not to drive and avoid strenuous activities. Some patients may experience a slight increase in pain for several days as the numbing medication wears off and while waiting for the steroid to work. The day following the injection, patients may return to their normal activities.
Epidural injections are not always beneficial. About half of the patients getting an epidural steroid injection will have relief of their pain. In some patients the relief may be substantial and long lasting. Some may only get partial relief and others may get no relief at all. If the first injection only gives partial relief, a second and, sometimes, a third injection may be recommended.