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What is an Epidural?

What is an Epidural?

Most of us hear the word epidural and immediately associate it thoughts pregnant women in Labor. Others know that it is also used to provide Anesthesia and analgesia (fancy words for Pain Relief) for some surgical procedures.

Despite the word “Epidural” being widely known, many misconceptions remain. There is very little understanding among the general public of the term and its applications in chronic pain management. Very often a patient will learn they are to undergo treatment with epidural injections, and they will say something along the lines of “An Epidural? Like the pregnant ladies?” followed by some nervous joking about whether they will be having a girl or a boy today.

A textbook (just kidding, I shamelessly used Wikipedia!) definition of Epidural would read something like this:

Epidural administration (from Ancient Greek ἐπί, “on, upon” + dura mater) is a medical route of administration in which a drug such as epidural analgesia and epidural anaesthesia or contrast agent is injected into the epidural space around the spinal cord. The epidural route is frequently employed by certain physicians and nurse anaesthetists to administer local anaesthetic agents, and occasionally to administer diagnostic (e.g. radiocontrast agents) and therapeutic (e.g., glucocorticoids) chemical substances. Epidural techniques frequently involve injection of drugs through a catheter placed into the epidural space. The injection can result in a loss of sensation—including the sensation of pain—by blocking the transmission of signals through nerve fibres in or near the spinal cord.

In this picture, you can observe the epidural space depicted in purple just above the Dura mater represented by the orange line.  The needle is dispensing medication “epidurally” as the medication bathes the Dura. In other words, EPIDURAL: refers to the ROUTE OF ADMINISTRATION. To further explain this, we would need to discuss two things, one is an Anatomical term. Dura Mater, and the meaning of the prefix “Epi”

Brain tissue has the consistency of gelatin, aside from being vitally important in keeping us alive, our nervous system is extremely fragile and as such it is protected inside a hard enclosure formed by the skeletal system i.e.: Skull and Spine. Further protection is provided by a layer of membranes that act as a shock absorber. One of these layers, the thickest and most important one is called the Dura Mater. Think of it like putting a delicate vase into storage, it’s not enough to just stick the vase in a box, you need some packing material like crumpled newspaper to ensure it doesn’t roll around and possibly break while inside the box.

Figure 1: If you were to imagine your skull as this box, your brain and spinal cord would be represented by the red vase, then the Dura Mater serves just about the same function as the bubble wrap does in protecting the vase.

Epi, is a prefix derived from the ancient Greek language, which literally means “On top of” or “Above”
Epidural = Above the Dura Mater.

Now that we know this, we can go back to discussing what this all means for you as a patient.

Epidural injections can be used to treat pain different parts of the body. This pain can affect your neck, shoulders, arms, back and legs.

The epidural space can be accessed at certain points throughout the spines length. By Placing a needle just above the Dura Mater or Epidurally if you will, you can treat pain effectively by directly targeting the affected area rather than “numbing” the whole body using oral or injected medication.

In our office the doctor usually performs epidurals using one of two approaches, Transforaminal and Intralaminar, (These terms which refer to where on vertebrae the needle is advanced towards, straight through the center or slightly off to one side, but, we can discuss more about this in a future post). The suitability of each is determined by taking into consideration some of the characteristics your pain exhibits such as whether its diffuse, or along a defined area. On whether your pain is limited to one side of your body or affects both, and a whole host of other factors considered when determining your best treatment plan.

Figure 2: In this photograph we see a needle placed in the Epidural Space of our model using the Intralaminar approach, The needle is inserted midline in between vertebrae.
Figure 3: For a Transforaminal Epidural the needle is inserted at a slighly more lateral point and directed towards the foramen on either side of the vertebrae.

I hope this helps you ease any anxiety you might have about getting an Epidural steroid injection. If you have any further questions comments you would like to add or If there is any subject you would like to see discussed feel free to reach out to us at crodriguez@lenchig.com or call us at 954-493-5048