This procedure is indicated for treatment of arm or leg pain due to pinched nerves in the neck or low back. Sometimes chronic neck or low back pain responds to it. At times it is performed in the thoracic spine. In this approach, a steroid is injected directly around the dura, the sac around the nerve roots that contains cerebrospinal fluid (the fluid that the nerve roots are bathed in). Prior to the injection, the skin is anesthetized by using a small needle to numb the area in the low back (a local anesthetic).
Overall success rate in terms of giving some relief is about 50%. The benefit from the procedure may last a few days, weeks, or many months. It helps patients deal with the pain while their own body is recovering from the cause of the radicular pain such as disc herniation or spinal stenosis.
The procedure may be performed up to three times a year. Side effects include aggravation of diabetes, infection, scarring of the nerves, and rarely avascular necrosis of the hip joints causing permanent arthritis in the hips. Other risks include nerve injury, dural tear causing persistent spinal headache, and very rarely paralysis if epidural hemtoma occurs.
Usually radiologic control such as C arm fluoroscopy is used for insertion of the needle. Radiographic dye is injected to make sure that the needle is in the epidural space. A mixture of local anesthetic and steroids is injected. Potential complications include permanent irreversible painful scarring of the nerve roots called Arachnoditis and spinal headaches and infection called epidural abscess. Paralysis can occur if patient is taking blood thinners such as Coumadin or aspirin and it is absolutely important that patients stop taking all types of blood thinners at least one week prior to the procedure.
Patients need to bring a driver with them to the procedure as they are not allowed to drive home by themselves after the procedure.
Epidural Injections Help Reduce Inflammation
Injecting around the dura sac with steroid can markedly decrease inflammation associated with common conditions such as spinal stenosis, disc herniation, or degenerative disc disease. It is thought that there is also a flushing effect from the injection that helps remove or "flush out" inflammatory proteins from around structures that may cause pain.
Epidural Steroid Injection Success Rates
Epidural injections are done under sterile conditions very similar to surgery. Still, anytime a needle is inserted into the body there is a small chance of infection. Since the needle in an epidural is going near the spine, an infection is much more serious if it occurs. The chance that an infection will occur is extremely small.
An epidural injection can result in a hematoma. A hematoma is simply a collection of blood due to an injury to a blood vessel. An epidural hematoma can be serious if it is big enough to cause enough pressure on the spinal nerves so that they quit working. This can cause problems with the bowels and bladder.
Because the epidural injection actually paralyzes the nerves to the bowel and bladder for a short period, you may not have control over your bladder for one to two hours.
There is always a small risk of damage to the spinal nerves. The spinal cord is a bundle of millions of nerves that connects the brain with the rest of the body. If the epidural needle directly injures the spinal nerves, this can cause serious neurologic problems.