The spinal cord is covered by small layers of linings that encircle it. The space between the two outer layers is called epidural space that is filled with fat and blood vessels.
The needle is placed in the epidural space and steroids along with normal saline or local anesthetics are injected to flush out chemical irritants that may be the source of back and leg pain. Steroids reduce the swelling and inflammation around the nerve roots. It does not shrink back the herniated disk.
Sciatica is caused by the compression on the spinal nerves, usually by a herniated disk. The other sources of nerve compression may be spinal stenosis that is tightness of the spinal columns around the cord or degenerative arthritis with tightness around the nerve root openings.
In most cases, acute sciatica settles down itself in four-six weeks with conservative treatment, including anti-inflammatory medications and physical therapy. If patient doesn’t respond to conservative treatment, epidural steroid may help the recovery process.
Procedure is performed in a physician’s office or surgery center. Light sedation is used to make it comfortable for the patient in the surgery center. A needle is carefully placed in the epidural space under fluoroscopy. A small dose of dye is injected to confirm the position of the needle in the epidural space. It is followed by injected steroids along with local anesthetics.
What to expect after the injection
About 50% of the patients experience pain relief after the epidural steroid injection that lasts from weeks to years. It may take up to 1-3 epidural injections for the pain relief. These injections are done about 2-3 weeks apart.
If sedation is used for the injection, patient is advised not to drive a motor vehicle or operate heavy machinery up to 24 hours after the procedure.
Possible complications are infections, bleeding, nerve damage, or spinal headaches. Spinal headaches are treated successfully by epidural blood patch.
In a sleeve root injection, the needle is placed around the exit of the nerve roots from the spinal canal. Sleeve root injection is usually used as diagnostics tool to identify nerve root involvement as a source of pain or therapeutic purposes to relieve the pain from sciatica or neck pain.
Sleeve root injections are always performed under fluoroscopy. The complications side effects and recovery time is pretty much similar to epidural steroid injection.