What is an interlaminar epidural steroid injection (ESI)?
An ESI is the injection of a steroid medication into the epidural space.
What is the purpose of an ESI?
The steroid medication is a powerful anti-inflammatory medication. Pathologic changes of the spine often lead to inflammation. This inflammation is a large cause of pain. An injection of steroid can substantially decrease this inflammation and thereby lead to a significant reduction in pain.
How is the procedure performed?
You will lie face down on the procedure table. The injection site is sterilized with either iodine or chlorhexidine. The site to be injected is numbed with a local anesthetic, and a needle is directed to the target area. X-ray guidance is used to ensure proper placement and positioning of the needle. Contrast (x-ray dye) may be injected to be sure the needle is in the proper position. Once proper needle placement is confirmed, the steroid solution is slowly injected.
How is an ESI different from a TF (transforaminal epidural steroid injection)?
Both an ESI and a TF are epidural steroid injections. They both involve injecting steroid into the epidural space to decrease inflammation and alleviate pain. The main difference is that an ESI spreads the medication into the back of the epidural space and along a more diffuse pattern, hitting multiple levels during a single injection. Alternately, a TF spreads the medication into the front of the epidural space and is more specific to certain levels and certain affected nerve roots. Your doctor will choose one technique vs the other, based on various criteria, in trying to get the best results for you.
Will the procedure be painful?
The injection can be painful, although most patients express feeling pressure in the site during the procedure, please notify the physician right away so that comforting measures can be taken. If you take medications for diabetes, these medications may need to be adjusted the morning of the procedure. Your primary care physician can help you with this adjustment.
What are the risks and side effects?
The complication rate for this procedure is very low. Whenever a needle enters the skin, bleeding or infection can occur. If the bleeding accumulates inside the body, it forms a hematoma. If the hematoma pushes against structures of the spine, surgery may be required to evacuate it. Another potential complication is a “spinal headache”, which can occur when attempting an ESI. If this occurs, it usually resolves on its own within three to five days. Alternately, there is another procedure that can be performed to cure the headache within a matter of minutes. Some other serious but extremely rare risks include paralysis and death.
You may have an allergic reaction to any of the medications used. If you have a known allergy to any medications, especially x-ray contrast dye or local anesthetics, notify our staff before the procedure takes place.
How long does it take for the procedure to work?
The steroid medication begins to take effect in one to two days at which point you should start to see some benefit. The steroid effect continues to get stronger and stronger such that the peak effect occurs at about two weeks. Thereafter, the effect will stabilize and should last several weeks to months. Typically, the pain relief experienced from this procedure lasts 3-6 months, but there is significant variability from patient to patient and from one procedure to another. If and when the pain starts to return, this procedure can be repeated to try and attain some pain relief once again. Keep in mind that this injection may work very well for pain certain areas but may not help with others. This is normal. Areas of pain that do not respond may need other treatments, which you can discuss with your doctor.