Steroid Injections for Back and Neck Pain

Lumbar Epidural Injection Procedure Video

Where the Steroids are Injected

The epidural space (or extradural space or peridural space) is a part of the human spine. It is the space inside the bony spinal canal, but outside the membrane called the dura mater (sometimes called the “dura”). In contact with the inner surface of the dura is another membrane called the arachnoid mater (“arachnoid”). The arachnoid encompasses the cerebrospinal fluid that surrounds the spinal cord.

Epidural Steroid Injections

An epidural injection, or epidural steroid injection, may be used to help reduce the pain caused by a herniated disc, degenerative disc disease, or spinal stenosis. These spinal disorders often affect the cervical (neck) and lumbar (lower back) areas of the spine.

The medicine used in the injection is usually a combination of a local anesthetic (e.g. bupivacaine) and a steroid (e.g. triamcinolone). The technique and risks of the procedure are similar to those for standard epidural analgesia. The effects of an epidural steroid injection vary, but permanent benefit is unlikely. The technique is believed to work by reducing the inflammation or swelling, or both, of the nerves in the epidural space.

Some patients who have some residual pain after the first injection may receive a second or third epidural steroid injection. Patients who do not receive any relief from the first injection are unlikely to benefit from a second injection.

Side Effects of Epidural Injections

Note: Yes I know that some of these side effects refer more to pregnant women than back pain, but the process is the same, it’s the injected drugs that differ.

In addition to blocking the nerves which carry pain, local anaesthetic drugs in the epidural space will block other types of nerves as well, in a dose-dependent manner. Depending on the drug and dose used, the effects may last only a few minutes or up to several hours. This results in three main effects:

  • Loss of other modalities of sensation (including touch, and proprioception)
  • Loss of muscle power
  • Loss of function of the sympathetic nervous system, which controls blood pressure

Pain nerves are most sensitive to the effects of the epidural. This means that a good epidural can provide analgesia without affecting muscle power or other types of sensation. The larger the dose used, the more likely it is that the side-effects will be problematic.

For example, a laboring woman may have an epidural running during labor which is providing good analgesia without impairing her ability to move around in bed. She requires a Caesarean section, and is given a large dose of epidural bupivacaine. After a few minutes, she can no longer move her legs, or feel her abdomen. Her blood pressure is noted to be lower and she is given an intravenous infusion of ephedrine or phenylephrine to compensate. During the operation, she feels no pain.

Very large doses of epidural anaesthetic can cause paralysis of the intercostal muscles and diaphragm (which are responsible for breathing), and loss of sympathetic function to the heart itself, causing a profound drop in heart rate and blood pressure. This requires emergency treatment, and in severe cases may require airway support. This happens because the epidural is blocking the heart’s sympathetic nerves, as well as the phrenic nerves, which supply the diaphragm.

It is considered safe practice for all patients with epidurals to be confined to bed to prevent the risk of falls. The loss of the sensation of needing to urinate may require the placement of a urinary catheter for the duration of the epidural.

Opioid drugs in the epidural space are very safe (as well as effective). However, very large doses may cause troublesome itch, and rarely, delayed respiratory depression.

For patients with nerve root pain involving one or two roots, I believe that fluoroscopically guided foraminal injections will prove to be superior to the approaches that do not use x-ray guidance. Epidurals in general, but especially foraminal injections, do not appear to be as effective if the pain is caused by widespread degenerative or arthritic problems in the spine. – Steven Richeimer, MD

Posted by on Jul 17th, 2008 and filed under Back Pain, Neck Pain. You can follow any responses to this entry through the RSS 2.0. You can leave a response by filling following comment form or trackback to this entry from your site

You must be logged in to post a comment Login