When most people hear the term “epidural” they automatically think of an anesthetic used for childbirth. The reality, though, is that epidural anesthetics have a wide range of uses in surgery. Epidurals not only reduce pain, they also may improve outcomes from surgery for some patients. For that reason, epidurals are becoming more common for many operations on the chest, abdomen, pelvis, and legs. You might be offered one as part of your operation. With that in mind, let’s review some basic information about epidurals:

What Is an Epidural?

An epidural anesthetic is a local anesthetic injected around the major nerves of the spine to numb them at their origin, before they go out to the body where they sense pain. In the case of an epidural, this local anesthetic (which is similar to the local anesthetic you may have had for dental procedures or simple stitches) is injected through a very thin tube into the “epidural” space, the area right outside of the spinal cord where nerves start heading out of the spinal column. That tube is put in place through a small needle that’s inserted between two of your vertebrae. Because the needle is removed, leaving only the very flexible tube, epidurals can be left in place for days after surgery, to provide continuous pain control and decrease the need for other pain medications, including narcotic pain medicines.

How Is an Epidural Placed?

Epidurals are placed by your anesthesia team before surgery. This may be done in the pre-op area or in the operating room before you go to sleep. Because you need to let your anesthesiologist know when and where you feel numb from the anesthetic, epidurals are generally placed while you are still awake.

After cleaning the skin over the lower part of your spine and injecting a small amount of local anesthetic to numb the skin, the anesthesiologist will insert a small needle into the epidural space and then advance the small tube through it. You’ll then get what’s called a “test dose” of anesthetic, to be sure that the medication is working and affecting the appropriate nerves.

While there are some procedures that require an epidural alone, such as childbirth, in most operations where an epidural is used you will also get a general anesthetic, meaning that you will go to sleep for the operation. The epidural may be used to supplement your pain control while you’re asleep, but it is mostly used to help to control pain after you wake up.

When Is an Epidural Right for You?

Epidurals can be used for most abdominal, pelvic, and leg operations, as well as some operations in the chest. Obviously, they are most effective when used to reduce pain from large incisions – using them for minimally invasive or laparoscopic surgery, where the incisions are small, provides less benefit.

Epidurals cannot be used in the upper part of the spinal column, because they could numb the nerves that supply the heart and lungs, which would be dangerous.

Although the available evidence doesn’t prove it conclusively, there is some suggestion that epidurals can help not just with pain control, but with outcomes from surgery. This is probably because the pain response, even when you’re unconscious, causes the release of chemicals that promote inflammation and can put stress on your heart and lungs. Patients with advanced heart or lung disease should make a point of discussing with their surgery and anesthesia teams whether an epidural would be appropriate for their operation.

When Is an Epidural Not Such a Good Idea?

There are certain cases in which an epidural may not be a good idea. If you have a history of certain back operations, take blood thinners, or have unstable vital signs or are getting an emergency operation, you shouldn’t get an epidural. Likewise, if you have a systemic infection or an allergy to local anesthetics, you probably shouldn’t get an epidural.

Although epidurals are generally very safe, they do have very real risks. The most common side effect is a headache, caused by leaking fluid from your spinal column. This happens in about 1% of patients. A much, much smaller number of people develop infections or bleeding in the spinal column, both of which can be life threatening. So, just like with any medical procedure, be sure to talk with your medical team about whether the benefits of an epidural outweigh the risks.

Resources for More Information

I obtained many of the details for this piece from this nice review article about some the risks and benefits of epidural anesthesia. It’s written for a medical audience, but for being in medicalese, it’s actually fairly readable.

The NIH has also put together a nice interactive guide to epidurals. It gives a nice description of how an epidural is placed, though the illustrations aren’t great. One thing I would note, though, is that in my experience patients with epidurals can move around well and don’t always require bladder catheters.

Of course, the best source of information about your specific case is your own medical team. For more information about whether an epidural is a good option for you, be sure to ask your anesthesiologist about it when you have your pre-operative anesthesia evaluation.

This story originally appeared in the  Health Dialog Care Compass Blog.