What is an epidural injection?
The epidural space is located along the entire line of the spinal canal one layer superficial to the spinal fluid. Medication such as a corticosteroid and / or local anesthetic is injected in the epidural space with the use of a needle or catheter (small tube).
What are corticosteroids and how do they work?
Corticosteroids are a group of related compounds that are naturally occurring in the body as well as synthetically produced. Corticosteroids act to regulate salt and water balance as well as decrease inflammation. They are used in the treatment of pain and disease primarily for their anti-inflammatory effects. The anti-inflammatory action helps to reduce pain by blocking inflammatory chemicals that sensitize nerves and nerve receptors. They should not be confused with anabolic steroids that athletes have used to build muscle mass.
What are the possible side effects of injected corticosteroids?
Injectable fat soluble preparations of corticosteroids have much fewer side effects than oral or intravenously administered corticosteroids. The effects are usually dose related and will occur most frequently in patients who use these medications over a long period of time. Excessive corticosteroids can result in salt and water imbalances, gastrointestinal disturbances, weakness, increased risk of infection, decreased stress response, osteoporosis and depression.
What sort of conditions are treated using epidural steroid injections?
Epidural steroid injections are used to treat conditions that affect the spine from the neck to the lower back. These conditions include herniated discs, protruding discs, degenerated discs, osteoarthritis of the spine, spinal stenosis, and scar tissue or other changes following neck or lower back surgery. Patient complaints can include pain in the neck, shoulder, upper or lower back, arms or legs. Patients may also have complaints of numbness or weakness in the extremities.
How is the injection performed?
Ideally, the needle or catheter is placed at the appropriate segment of the spinal column with the use of a rotating x-ray machine called a fluoroscope. A front to back and side to side image is needed to determine the position of the needle in three dimensions. After determining the needle tip position with respect to the bony landmarks, contrast dye is injected to help confirm placement. After the contrast confirms proper placement, the medications are then injected. X-ray guidance significantly improves accuracy and safety.
Do all physicians use x-ray guidance in performing epidural injections?
Not all physicians use x-ray in performing epidural injections. These physicians use a technique in which the “feel” of the needle is used to determine location. However, over the last 15 years, radiology studies have shown that this technique misses the epidural space about 30 percent of the time. In some cases, the medication ends up outside the spinal canal in fat tissue or in a vein. Many times, the medication can end up on the wrong side or at the wrong level.
What are the side effects and risks associated with epidural injections?
Most patients will experience some injection site tenderness for 1 – 3 days following the injection. This can be remedied with an ice pack on the injection site immediately following the procedure, and heat if the pain persists after 24 hours. Headaches may occur if the needle enters the spinal fluid. This occurs much more commonly when procedures are performed without x-ray guidance. Infection, bleeding, and nerve injury are very rare reported side effects. The use of sterile technique and x-ray guidance further reduce the chances of these problems occurring.
Do the injections hurt?
There can be some local discomfort with the needle placement. Local anesthetic is used to numb the area. Sedation can be used to relax the patient.
How long does it take for the injections to work?
It usually takes 1 to 3 days for the corticosteroids to have their effect. However, some patients take up to seven days to notice the full effect. Most patients experience some relief after the first injection. Subsequent injections may need to be performed to increase the degree of pain relief.
How long does the pain relief last?
The injected corticosteroids are fat soluble and generally are active for about one month. However, the clinical relief depends on several factors and can last much longer. The most important is the nature of the patient’s condition. In some cases, healing after injury may take 6 months to one year. In other cases, the condition is chronic and injections may be needed on an intermittent basis. Patients are encouraged to go through physical therapy for strengthening exercises during the period of time when the pain has been reduced.
What about physical therapy?
Physical therapy and rehabilitation is essential in treating many patients with spinal conditions. By making the muscles around a spine into a “muscular corset” loads can be reduced on the nerves, disks, and joints of the spine. One of the major goals of the epidural steroid injection is to reduce pain and allow the patient to participate more effectively in physical therapy.
What if I don't get any relief from the epidural injections?
If you do not receive benefit from the epidural injection, other structures may be responsible for your pain. This could include the disk, joints, ligaments, or muscles surrounding the spine. You may require further imaging studies or other diagnostic injections to better identify and treat the source of your pain.