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What is an epidural steroid injection?

A steroid injection includes both a corticosteroid (e.g., triamcinolone, methyl-prednisolone, dexamethasone) and an anesthetic numbing agent (e.g., lidocaine or bupivacaine). The drugs are delivered using precise imaging into the epidural space of the spine, which is the area between the bony vertebra and the protective spinal sac surrounding the spinal nerves and cord. 

We use imaging guidance including fluoroscopy or CT to target precisely the area that is causing your pain. 

Corticosteroid injections can reduce inflammation and can be effective when delivered directly into the painful area. Unfortunately, the injection does not make a herniated disc smaller; it only works on the spinal nerves by flushing away the proteins that cause swelling. The injection is only a temporary solution The pain relief can last from days to months, allowing your spinal condition to improve with physical therapy and an exercise program.


Why is it done?

 Patients with pain in the neck, arm, low back, or leg (sciatica) may benefit from ESI. Specifically, those with the following conditions:

  • Spinal stenosis: A narrowing of the spinal canal and nerve root canal can cause back and leg pain, especially when walking.

  • Spondylolisthesis: A weakness or fracture between the upper and lower facets of a vertebra. If the vertebra slips forward, it can compress the nerve roots causing pain.

  • Herniated disc: The gel-like material within the disc can bulge or rupture through a weak area in the surrounding wall (annulus). Irritation, pain, and swelling occur when this material squeezes out and comes in contact with a spinal nerve.

  • Degenerative disc: A breakdown or aging of the intervertebral disc causing collapse of the disc space, tears in the annulus, and growth of bone spurs.

  • Sciatica: Pain that courses along the sciatic nerve in the buttocks and down the legs. It is usually caused by compression of the 5th lumbar or 1st sacral spinal nerve.

ESI has proven helpful for some patients in the treatment of painful inflammatory conditions. ESI can also help determine whether surgery might be beneficial for pain associated with a herniated disc. When symptoms interfere with rehabilitative exercises, epidurals can ease the pain enough so that patients can continue their physical therapy.

What are the risks?

With few risks, ESI is considered an appropriate nonsurgical treatment for some patients. The potential risks associated with inserting the needle include spinal headache from a dural puncture, bleeding, infection, allergic reaction, and nerve damage / paralysis (rare).

Corticosteroid side effects may cause weight gain, water retention, flushing (hot flashes), mood swings or insomnia, and elevated blood sugar levels in people with diabetes. Any numbness or mild muscle weakness usually resolves within 8 hours in the affected arm or leg (similar to the facial numbness experienced after dental work). Patients who are being treated for chronic conditions (e.g., heart disease, diabetes, rheumatoid arthritis) or those who cannot temporarily discontinue anti-clotting medications should consult their personal physician for a risk assessment.

Epidural steroid injections do not induce weight gain. … However, steroids have widespread effects on almost all body systems, such as suppression of the pituitary-adrenal axis with consecutive weight gain and osteoporosis.

Reasons to avoid this procedure?

You should avoid the procedure if there is any signs or suspicion of an infection, including fever or elevated WBC. Because we use imaging, this should be avoided if you think you could be pregnant. 

How do you prepare?

If you take any type of blood thinners you should let us know. Depending on the type of blood thinner you take, you will need to stop that medication before the procedure. Please refer to pre-procedure instructions for detailed instructions about your medications.

 If the procedure is performed with IV sedation, you will need to fast for 8 hours before the procedure. We recommend no eating or drinking after midnight before the procedure. Generally, you should take your daily morning medications with a small sip of water.

 Please leave all valuables such as jewelry, credit cards and money at home on the day of the procedure. Family members may wish to bring a magazine or book to read during the wait time.

Although the procedure is an outpatient endeavor, we usually perform the procedure at El Camino Hospital with state of the art equipment. Please check in with patient registration at the time of your procedure. It is located in the main lobby as you enter the main doors. 


How is the procedure done?

You will be placed in the procedure table lying on your side. The procedure usually takes about 10-15 minutes, followed by a recovery period.

The goal is to inject the medication as close to the painful nerve as possible. The type and location of injection depends on your condition and symptoms. The procedure is performed under imaging guidance. We have the ability to use x-rays (fluoroscopy) or CT guidance.  Local anesthetic is used to numb the treatment area so discomfort is minimal throughout the procedure. The procedure can be done with local anesthesia only or in some cases we can provide mild sedation (fentanyl and midazolam).  This is the same type of sedation commonly used for endoscopies and colonoscopies. 

 The imaging allows us to precisely place the needle  in the affected area.

There are several types of ESIs:

  • Cervical ESI (neck). The needle entry site is from the side of the neck to reach the neural foramen, just above the opening for the nerve root and outside the epidural space (Fig. 2). Contrast dye is injected to confirm where the medication will flow.

  • Lumbar ESI (low back). The needle entry site is slightly off midline of the back to reach the nerve canal (Fig. 3). Contrast dye is injected to confirm where the medication will flow.


When the needle is correctly positioned, the anesthetic and corticosteroid medications are injected into the epidural space around the nerve roots. The needle is then re­moved. Depending on your pain location, the procedure may be repeated for left and right sides and several spinal levels may be injected.

How painful is the procedure? 

It is usually not a very painful procedure. You may feel a temporary stinging or burning sensation when the local anesthetic is used. It feels like a bee sting. When the medication is injected in the nerve you can temporally feel a sharp pain that radiates to the area of the normal pain. Although this can be unpleasant usually indicates the area being treated is the correct area. 

How long do epidural injections last? 

Some patients may feel an instant relief caused by the injection of the local anesthetic. Although this is good and means we were in the right place, it only lasts 1-2 hours. The corticosteroid shots may take up to a week to work. I may give you short-term relief from back pain and sciatica. On average, pain relief from the shots lasts about 3 months. Our hope is  that this may be enough time for your back to heal so your pain doesn’t come back. Also it may relieve the pain temporarily so you can actually perform physical therapy. 

What you can expect after the procedure?

Most patients can walk around immediately after the procedure. After being monitored for a short time. However, be careful and make sure you can feel your legs before you get up. Sometimes,  temporary leg weakness or numbness can occur and may last 1-2 hours. Because of that, it is a good idea to have someone to drive you home.

Typically patients resume full activity the next day. Soreness around the injection site may be relieved by using ice and taking a mild analgesic (Tylenol).

You may want to record your levels of pain during the next couple of weeks in a diary (pain diary attached). You may notice a slight increase in pain, numbness, or weakness as the numbing medicine wears off and before the corticosteroid starts to take effect.

Although injections can help the pain, we consider physical therapy or even a guided home exercise program to be invaluable.

How many injections can I get in a year? 

Some experts recommend no more than 3 injections in a 12-month period, owing to concerns about the adverse events of chronic steroid administration, both locally and systemically. However, other experts believe that up to 6 injections per year is safe.

What should I watch for?

Pain and soreness after the procedure is considered normal. Pain should subside over the next 2-3 days following the procedure. Worsening of pain, redness, warmth or discharge at the site of the procedure may be signs of infection.  

If pain continues, worsens or signs of an infection are present please call our office immediately at 650-404-8445 and seek immediate medical attention.

Do you have any additional questions?

Please let us know if you have any additional questions that we can answer for you prior to your procedure. Please do not hesitate to call our office at 650-404-8445, we look forward to serving you.

General Instructions:

  • If you received sedation, you should not drive, consume alcohol, operate heavy machinery or make any important decisions for the remainder of the day.

  • You may resume your regular activities as tolerated (including driving) after 24 hours, unless you have been restricted for another reason.

  • No exercising, lifting heavy objects or strenuous activity for the next two weeks or until you have had your follow-up with us at our Interventional Radiology clinic.

  • You may shower 24 hours after the procedure.

Pain Management
  • You may use over the counter medication such as Acetaminophen (Tylenol) or Ibuprofen (Advil /Motrin) for minor discomfort, unless you are restricted from taking these medications.

  • If you have pain at the injection site, application of an ice pack to this area should be helpful.

  • If you feel that Tylenol or Advil are not enough to control your pain, please contact the Vascular and Interventional Radiology Clinic at 650-404-8445.

  • You can resume your normal diet. Some patients may develop nausea after the sedation. Therefore light meals are recommended until you know that you can eat without problems.

  • Make sure you drink enough fluids.

  • You can take a shower tonight. You should not soak the procedure site in water (eg. bath and swimming pool) for 1 week.

When can I return to work? 

Most people do return to work the next day.

When should you call your physician?
  • Chills or fever  > 101 F

  • Worsening of redness or worsening of pain in the procedure site.

  • New lower extremity numbness or tingling.

You can reach your Interventional radiologist at (650) 404-8446

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