Epidural results and precautions

As with any medical procedure, there are certain drawbacks and potential risks associated with an epidural steroid injection for back pain, leg pain or arm pain. One of the most important issues to consider is that the procedure only tends to significantly lessen the patient’s pain about half of the time.

Effectiveness of epidural injections
Unfortunately, epidural steroid injections are not always effective—it is estimated that they help relieve the patient’s pain only about 50% of the time. In some cases the pain relief will be permanent. In others, the pain will be lessened enough to allow the patient to progress with rehabilitation and exercise, which helps the patient heal and find pain relief on a long-term basis.

If excellent pain relief is obtained from the first epidural injection, there will be no need to repeat it. If there is a partial benefit (greater than 30% relief from pain) the epidural injection can be repeated for possible additional benefit, or it may be necessary to conduct additional tests to more accurately determine what is causing the patient’s pain. Up to three epidural steroid injections may be performed within a one-year period, spaced at least two to four weeks apart. If the initial injection provides minimal benefit (less than 30% pain relief) the physician may either repeat the injection, or try a different type of injection or treatment.

Potential risks and complications
As with all invasive medical procedures, there are potential risks associated with epidural steroid injections. However, in general the risk is low, and complications are rare. Potential risks include:

Infection. Minor infections occur in 1% to 2% of all injections. Severe infections are rare, occurring in 0.1% to 0.01% of injections.
Bleeding. A rare complication, bleeding is more common for patients with underlying bleeding disorders.
Nerve damage. While extremely rare, nerve damage can occur from direct trauma from the needle, or secondarily from infection or bleeding.
Dural puncture ("wet tap"). A dural puncture occurs in 0.5% of injections. It may cause a post-dural puncture headache (also called a spinal headache) that usually gets better within a few days. Although rare, a blood patch may be necessary to alleviate the headache from a dural puncture.

For a lumbar epidural injection, paralysis is not a risk since there is no spinal cord in the region of the epidural steroid injection. In addition to risks from the injection, approximately 2% of patients will experience side effects from the steroid medication, such as:

Transient flushing with a feeling of warmth (‘hot flashes’) for several days
Fluid retention, weight gain, or increased appetite
Elevated blood pressure
Mood swings, irritability, anxiety, insomnia
High blood sugar—diabetic patients should inform their primary care physicians about the injection prior to their appointment
Transient decrease in immunity
Cataracts—a rare result of excessive and/or prolonged steroid usage
Severe arthritis of the hips or shoulders (avascular necrosis)—a rare result of excessive and/or prolonged steroid usage

Lumbar epidural steroid injections should not be performed on patients who have a local or systemic bacterial infection, are pregnant (if fluoroscopy is used) or have bleeding problems. Epidural injections should also not be performed for patients whose pain is from a tumor or infection, and if suspected, an MRI scan should be done prior to the injection to rule out these conditions.

Injections may be done, but with extreme caution, for patients with allergies to the injected solution, uncontrolled medical problems (such as congestive heart failure and diabetes), and those who are taking aspirin or other antiplatelet drugs (e.g. Ticlid, Plavix).

By: Ray Baker, MD
September 10, 2004