Epidural Injection

How does an epidural work?

At the core of your spine lies your spinal cord, a highway that carries signals from your body to your brain and vice versa, including orders from your brain to your body. The spinal cord is floating inside a tube of water called cerebrospinal fluid. 

Epidural space is the most favorite destination for a pain doctor. It is also closest to the spinal nerves for a doctor. Imagine going to an aquarium with a shark tank. You can stand behind the glass and see the sharks within a short distance. The glass is dura. The water is cerebrospinal fluid (CSF), and the shark represents the spinal cord. Where you stand is the epidural space. It is safe!

Not in the middle but to the extreme sides of this epidural space, the nerves branching off from the spinal cord pass to the skin, muscles, or other structures in your body. Also, the epidural space is in direct contact with the discs in your spine.

You may experience irritation of the nerves running through the epidural space, which can cause pain, numbness, tingling, or weakness in your body.

An epidural injection works by injecting anti-inflammatory medication, such as a steroid, into the epidural space. These medications would hug the nerves and calm down the irritated or inflamed nerves. Additionally, they will help decrease inflammation within the disc. Theoretically, they may attempt to shrink a disc that is out of place, which is referred to as a bulge or herniation. Think of it like applying steroid ointment on top of a rash. Afterwards, you expect the bulging of the skin to go down.

Probably you have heard about epidural injections during childbirth. More than 50% of people who give birth at a hospital choose to receive epidural analgesia. This is done in the low back. The purpose of that epidural injection is to have no sensation or movements from the waist down. The woman will be paralyzed temporarily for a few hours until the childbirth is complete. For decreasing the pain in the low back and legs outside of the pregnancy setting, we use very different medications to calm down the nerve without affecting your normal sensation.

Epidural injections can be done in any part of the spine, including the neck, mid-back, and low back.

People who have pain in their neck, arm, lower back, or leg due to the following conditions may benefit from epidural steroid injections:

• Spinal stenosis.
• Spondylolisthesis.
• Herniated disk (slipped, ruptured, or bulging disk).
• Sciatica.

Due to certain medical conditions, not everyone can have an epidural. These include being on a blood-thinning medication or having uncontrolled diabetes. Because of this, it’s essential to discuss your medical history and any concerns with your healthcare provider.

If you’re unable to undergo an epidural procedure, we may recommend another type of pain relief, or we may have you wait until a better time to have your surgery.

How do we minimize pain or anxiety for injections?

You have two choices:

• We can do it while you are entirely awake. We numb your skin and tissues below it with a skinny needle and numbing medication. It is very tolerable, and the pinch is not worse than the pinch of a flu shot. You do not need to fast, and you can drive back home or return to your work after the injection!
• We use sedation. We inject a medication named Propofol into your vein. You go to a deep sleep with no feeling of pain at all for about 10 minutes. We usually complete the injection in 3-4 minutes. You wake up after you are transferred back to your recovery room. You need to fast for 12 hours before sedation, and a family or friend should drive you home.

How do we do epidural injections?

• You will lie on a comfortable table on your stomach.
• Your doctor will thoroughly clean the area of your back with alcohol to minimize the risk of infection.
• We use a skinny needle to inject local anesthetic medication with a small needle near the area where we will insert the epidural. This is so you won’t feel as much pain when we insert the epidural needle, which is larger than a standard shot needle. But:
• We use a 20-gauge epidural needle for injections. A typical small paperclip (not the jumbo size) has a thickness close to that of a 20-gauge needle. The depth of the epidural space varies from person to person. Usually, it is about 2 inches or so deep.
• Once the area is numb, we will use a live X-ray to help guide the epidural needle to the precise position. Performing this injection requires simultaneous tactile and visual cues. We will locate your epidural space and drive the needle there. Remember, everything is watched under live X-ray. No guessing!
• When the epidural needle is in the epidural space, we will make sure we are in the exact destination. We do so by injecting the contrast material.
• We will then slowly inject the medication, which is usually an anti-inflammatory medication, such as a steroid or corticosteroid, and a long-acting anesthetic.
• When the injection is done, we take out the needle and put a band-aid. You will rest for a few minutes to an hour.
• Watch a video about this procedure here. 

What happens after the epidural procedure?

Epidural steroid injections start working within two to seven days, and the pain relief can last several days or longer.

What are the risks or complications of getting an epidural?

Epidurals are usually safe, but there are risks of specific side effects and complications. Although rare, risks and complications that apply to all types of epidural procedures include:

• You will likely have a small bruise and some tenderness at the site of the epidural after delivery. This should get better in one to two days.
• Having low blood pressure can make you feel lightheaded.
• Experiencing a severe headache caused by spinal fluid leakage. Less than 1% of people experience this side effect.
• Getting an infection from the epidural procedure, such as an epidural abscess, discitis, osteomyelitis, or meningitis. This risk is about 1 in 10,000 people. 
• Having an adverse reaction to the medications, such as hot flashes or a rash.
• Experiencing bleeding if a blood vessel is accidentally damaged during the injection, which could cause a hematoma or a blood clot to form. The risk of serious bleeding, which can cause permanent paralysis, if the patient does not seek medical help, is 1 in 150,000 people. 
• Having nerve damage at the injection site.
• Temporarily losing control of your bladder and bowels. You may need a catheter (a small tube) inserted into your bladder to help you urinate.

Risks and complications that apply to epidural steroid injections specifically include:

• Experiencing a temporary increase in pain.
• If your provider uses fluoroscopy or a CT scan for imaging guidance, there will be minimal low-level radiation exposure due to the X-rays.
• If you have diabetes, a steroid injection will likely cause high blood sugar (hyperglycemia). This could last for several hours or even days.

Can getting an epidural cause back problems?

The new pain after an epidural is absolutely rare. There is a common but wrong belief that getting an epidural will cause more back pain. Please remember that an epidural is for decreasing pain, not making it worse!

This view is because many women, whether or not they had an epidural, have back pain following labor and delivery. This may result in back pain and discomfort as your pelvic bones and ligaments return to their pre-pregnancy positions.

Can getting an epidural cause long-term side effects?

These are very rare. These include spinal cord or nerve root damage from the epidural injection or from bleeding.

How long does an epidural last?

Nobody can predict how long the epidural steroid injection will be effective. Pain relief from an epidural injection may last for several days or even years.

Some people experience permanent pain relief if they have a new disk herniation. For people who have chronic pain, epidural steroid injections usually last 3 to 6 months or more.

When can I return to my normal activities after an epidural?

If you’ve had an epidural, do not drive for long distances or operate machinery for 24 hours after.