Definition and Overview

Epidural injections involve the administration of anesthetic or medication into the epidural space of the spine.

The spine is composed of many pairs of vertebrae. When they're connected to each other, they create the spinal canal, in which a space can also be found. On the outermost part is the epidural space. It is right next to the dura mater. Although "space" conjures the image of nothingness, it is actually composed of certain tissues, blood vessels, and nerve roots, among others.

The anesthesia used during epidural injection blocks the nerve activity, preventing the brain from communicating with the lower section of the body including the legs and feet. In the process, this area becomes numb and the person doesn't feel pain while remaining conscious throughout any procedure.

An epidural injection is often confused with spinal anesthesia since both seem to be delivered in the same area. One of the biggest differences is that in spinal anesthesia, the analgesic is administered directly into the spinal cord, so the numbing effect is a lot faster. Also, the procedure doesn't require any catheter unlike in epidural injection. Doctors also give higher doses of medicine in spinal anesthesia.

Who should undergo and expected results

Epidural injections are very popular with pregnant mothers who are already going into labor. Contractions can become particularly painful, especially when the women are already in their advanced stages of labor. To control the pain without compromising natural labor, an epidural anesthesia may be administered. The presence of the catheter allows the doctor to deliver the analgesic by stages, depending on the need and the safety of both the mother and the baby. Also, mothers can decide when they would want to receive an epidural.

Contrary to what some women believe, studies have shown that epidural injections do not have any side effects on the unborn. In fact, in some research, babies born from mothers who had an epidural had better Apgar scores than those from moms who opted for general anesthesia. Apgar score refers to the result of the test conducted on newborns to determine their health after delivery. This is the first examination infants go through.

Moreover, giving epidurals during the early stages of the contraction has been shown not to affect the overall duration of labor. It also doesn't have to lead to forceps delivery or Caesarean section.

Epidural injections may also be recommended for patients who have to undergo procedures including surgeries that involve the lower torso, such as the feet, legs, and abdomen. Patients may also consider this type of analgesia if they're looking for a faster recovery with lower risks.

Aside from analgesia, epidural injection is also needed to deliver medications such as steroids especially in patients who have been diagnosed with lumbar back pain. The lumbar region is the lowest part of the spine, which is connected to the sacral spine, which then forms part of the pelvic area. The lumbar spine doesn't have any spinal cord but loose spinal nerves. These nerves can be pinched, injured, or be affected by stenosis (narrowing) of the spine, generating chronic and sometimes severe pain in the lower back.

Epidural injections can also be applied in different regions of the spine, including the thoracic (middle) and cervical (around the neck and is directly connected to the brain).

Epidurals cannot be given to patients who have a history of low blood pressure, blood infection or disorder, and allergic reactions to the skin and anesthetic.

It may take around 20 minutes for the epidural injections to take effect in the body. All patients who receive epidural analgesia will be sent to a recovery room right after the procedure for observation. The sensation in the lower part of the body such as the legs and feet should return and the patient must be able to stand and walk. There may be a feeling of fatigue or dizziness as side effects of the procedure.

How the procedure works

Epidural injections are administered in slightly different ways depending on the reason. If it is for medication such as the delivery of corticosteroids that reduce the inflammation and irritation of the spinal nerves, the procedure may involve an epidural needle and an imaging system known as fluoroscopy.

During the procedure, the patient may be asked to lie on the side with the back curled. Sitting with the body slightly moved forward can also be an option. The area of the back where the epidural is going to be administered is cleaned with a topical numbing agent. An epidural needle is then inserted using fluoroscopy to serve as a guide. Once the medicine has been delivered, the needle is removed, and the patient is asked to rest for a few hours until the effects of the anesthesia have worn off.

If the injection is meant to provide pain relief during labor, a catheter is needed. This way, the medication can be given by doses. The initial steps are the same as lumbar epidural steroid injection. The catheter is inserted right after the needle has been removed. It stays in place all throughout the delivery process to ensure that the dosage can be increased at any given time. It is removed when the procedure is complete and the mother is on the way to the recovery room.

Possible risks and complications

The effects of the anesthesia are often minor and normal. These include dizziness, tingling or pressure in the lower part especially during the administration, and a sickening feeling in the stomach. These should subside as the anesthesia wears off. However, it's extremely important that only qualified anesthesiologists perform the procedure. In the most severe cases, it can lead to spinal infection such as meningitis, nerve damage, bleeding, and seizure.

Reference:

  • Chou R, Loeser JD, Owens DK, Rosenquist RW, et al; American Pain Society Low Back Pain Guideline Panel. Interventional therapies, surgery, and interdisciplinary rehabilitation for low back pain: an evidence-based clinical practice guideline from the American Pain Society. Spine. 2009;34(10):1066-77

  • Staal JB, de Bie RA, de Vet HC, et al. Injection therapy for subacute and chronic low back pain: an updated Cochrane review. Spine. 2009;34(1):49-59. Review

  • Jegede KA, Ndu A, Grauer JN. Contemporary management of symptomatic lumbar disc herniations.OrthopClin North Am. 2010;41:217-24

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