An epidural steroid injection (ESI) is a minimally invasive course of action that can help alleviate leg, back, arm, and neck pain caused by inflamed spinal nerves. ESIs may be carried out to relieve pain produced by spinal stenosis, or disc herniation. Medicines are dispensed to the spinal nerve through the epidural space, the region between the protective covering of the spinal cord and vertebrae. The effects of ESI tend to be brief. The objective is to reduce pain so that you may continue normal activities and a physical therapy program.

An epidural steroids injection comprises of both a long-lasting corticosteroid (e.g., triamcinolone, betamethasone) and an anesthetic numbing agent (e.g., lidocaine, bupivacaine). The two are delivered into the epidural space of the spine, which is the area between the protective covering (dura) of the spinal cord and the bony vertebrae. This area is filled with fat and small blood vessels.

What conditions can corticosteroid injections treat?

Corticosteroid injections can reduce inflammation and can be effective when delivered directly into the painful area. Regrettably, the injection does not make a herniated disc smaller; it only works on the spinal nerves. This liberation from pain can last from days to years, permitting you to improve your spinal condition with an exercise program and/or physical therapy. Patients with pain in the lower back, neck, leg, or arm may benefit from ESI. Especially those with the following conditions:

  • 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.
  • Spinal stenosis: A tightening of the spinal canal and nerve root canal can cause back and leg pain, especially when walking.
  • 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.
  • 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.
  • Spondylolysis: A weakness or fracture between the upper and lower facets of a vertebra. If the vertebra slips forward (spondylolisthesis), it can compress the nerve roots causing pain.

ESI has proven useful for many patients in the treatment of the above painful inflammatory conditions. ESI can also help establish whether surgery might be beneficial for pain linked with a herniated disc. When symptoms get in the way of rehabilitative exercises, an epidural can immediately deliver pain relief to patients, so that they can continue their physical therapy.

ESI should NOT be done on people who are pregnant, have bleeding problems, or have an infection. It may faintly elevate the blood sugar levels in patients with diabetes, usually for less than 24 hours. It may also briefly elevate blood pressure.

What are the risks of epidural steroid injection?

There are a few risks associated with epidural steroid injections and they tend to be rare. Risks may include:

  • infection
  • bleeding
  • nerve damage
  • dual puncture (wet tap)

What are some common uses of the procedure?

An epidural injection is one of many methods doctors use to relieve pain, along with physical therapy, oral medications, and surgery if a patient is not responding to conservative treatments.

An epidural injection may be performed to alleviate pain caused by:

  • A herniated or bulging disk that impinges nerves causing pain
  • Spinal stenosis (narrowing of the spinal canal)
  • Post-operative “failed back” surgery syndromes (chronic back or leg pain after spinal surgery)
  • Other injuries to spinal nerves, vertebrae, and surrounding tissues
  • Bone spurs

How should I prepare for the procedure?

You will receive specific instructions on how to prepare, including any changes you need to make to your regular medication schedule.

You may be instructed not to eat or drink anything for several hours before your procedure to prevent you from having an upset stomach following the injection or because some centers may offer sedation during the procedure. You will then be positioned on your stomach or side on a special fluoroscopic or CT table that will give the doctor easy access to the injection site(s). A nurse and/or technologist will help to make you as comfortable as possible, both during and after the procedure.

Plan to have someone drive you home after your procedure.

What does the equipment look like?

The injection itself will be administered with a syringe much like one that would be used for a routine vaccination. The doctor will fill the syringe with a small vial of medication. The type of medication used depends on individual patient needs.

The imaging guidance used, such as fluoroscopy or CT, will require additional equipment around the table. Both types of imaging are painless and involve the use of X-rays to obtain essential images

that allow the physician to place the needle in exactly the right location of the area of interest for the injection.

This exam typically uses a radiographic table, one or two x-ray tubes, and a video monitor. Fluoroscopy converts X-rays into video images. Doctors use it to watch and guide procedures. The x-ray machine and a detector suspended over the exam table produce the video.

The CT scanner is typically a large, donut-shaped machine with a short tunnel in the center. You will lie on a narrow table that slides in and out of this short tunnel. Rotating around you, the x-ray tube and electronic x-ray detectors are located opposite each other in a ring, called a gantry. The computer workstation that processes the imaging information is in a separate control room. This is where the technologist operates the scanner and monitors your exam in direct visual contact. The technologist will be able to hear and talk to you using a speaker and microphone.

How does the procedure work?

The different types of medications injected into the epidural space create different effects for patients. Corticosteroids act as anti-inflammatory agents, reducing swelling and nerve irritation to allow the nerve time to heal itself, thereby preventing further discomfort. By delivering an epidural injection directly into the epidural space, the medication moves throughout the epidural space, coating the inflamed or irritated nerve roots. Therefore, a lumbar (lower back) injection could alleviate pain associated with the lower back and the nerves traveling to the lower limbs, such as the sciatic nerves. Similarly, if an epidural injection is performed in the neck, it should spread throughout the cervical epidural space and provide relief to nerve roots in the neck which can also relieve arm pain. The duration of improvement from the epidural injection varies. Some patients have permanent relief. In others, the effects may not last long. In some cases, you may have a series of injections before you may benefit from significant relief. A patient may experience relief for a matter of days up to several months; however, the pain may eventually return, requiring another series of injections or an alternative treatment.