Pain Block Procedure

View the Semmes Murphey Pain Block Brochure in PDF format.

What is a Nerve Block?

When we use the term “nerve block”, we’re actually using a very old term that really doesn’t describe what we’re doing today. In the early days of surgery, general anesthesia was rather dangerous and difficult to administer. When possible, many surgeons preferred to use an injection of local anesthetic to numb the area involved so the patient could avoid the risks of general anesthesia.

Anesthesiologists studied the anatomy of the spinal cord and nerves in the body and developed ways to inject local anesthetic close to different nerves, “blocking” the nerve and providing anesthesia to a large part of the body. A “spinal block” involved injecting anesthetic into the spinal fluid, anesthetizing the lower half of the body. An “epidural block” involved injecting anesthetic inside the bones of the spine, but outside the sac of spinal fluid, providing a band of numbness around the middle of the body. Other nerve blocks could be used to numb an arm or a leg.



Today anesthetic nerve blocks are used mostly for labor and delivery to allow mothers to be awake but have pain relief during birth. Unfortunately, the term “nerve block” is still commonly used to describe dozens of pain relief injections. In reality, these injections aren’t blocking any nerves at all. Instead they are injecting dilute solutions of cortisone to relieve swelling and inflammation around the nerve. The nerve itself isn’t “blocked” or anesthetized.

While there are dozens of different injections used by interventional pain physicians, the most common are Epidural Steroid Injections. The epidural space is located inside the bones of the spine, but outside of the sack containing spinal fluid. By injecting into the epidural space medication can be delivered very close to nerves that are irritated by problems such as ruptured or degenerated discs, bone spurs (osteophytes), narrowing of the spine or nerve openings (stenosis), and other conditions.

The standard epidural block is performed by placing a needle between the bones (called lamina) in the middle of the spine and then injecting cortisone mixed with a dilute local anesthetic. The proper term for the procedure is an Interlaminar Epidural Steroid Injection, but many people still call it an “epidural block”. The procedure is further identified by the level of the spine at which it is performed such as lumbar (in the lower back) and cervical (in the neck).

In some cases, it is preferable to place the needle into the epidural space through the opening on the side of the spine that the nerves pass out of. This opening is called a foramen and this block is called a Transforaminal Epidural Steroid Injection. Less commonly, the epidural space is entered through an opening in the base of the sacrum (tailbone). That procedure is called a Caudal Epidural Steroid Injection.

Today, most epidural injections are fluoroscopically guided, which means the physician is watching the injection using live X-ray, not doing the procedure “blind” by just feeling the needle. So, now that you’ve read all the terminology, you should know what a “Fluoroscopically-guided transforaminal lumbar epidural steroid injection” actually is!

There are dozens of other types of injections used in interventional pain, but the epidural injections are by far the most common.


What will happen the day of my block procedure?

There are a number of different interventional pain injections, but the preparation and post-procedure care is similar for most of them. The procedures are generally performed in our Surgery Center so that we can use fluoroscopic (real-time X-ray) guidance and can give you intravenous (through an I. V.) sedation for the procedure.

Before the day of your procedure, a nurse will call to confirm the time you should arrive at the surgery center. This may vary slightly from the time you were originally given for your procedure as some procedures before or after yours may have cancelled or changed. The nurse will have a number of questions about medications you take and medical conditions you might have. You probably have answered these questions before, but it is important that this information be checked and rechecked to be certain no errors are made.

You should not eat or drink for 6 hours before your procedure, although you should take your scheduled medications with a sip of water. You must have a friend or relative drive you home after the procedure since you cannot drive after having sedation. Usually you will be at the Surgery Center for 2 hours or less.

After arriving at the Surgery Center you will be checked in, review the questions you were asked the day before with another nurse, change into a hospital gown and have an IV started in your hand or forearm. You will have a chance to talk to the doctor performing the procedure at this time and he will answer any questions you have.

The procedure itself is performed in an X-ray room. After being positioned on the table the nurse will administer some sedation through your IV. The sedation will leave you feeling drowsy and relaxed, but you will not be “put to sleep” for these minor procedures. Its not uncommon, though, for patients to not remember the procedure afterwards. Most interventional pain procedures take less than 20 minutes to perform.

After the procedure you will spend 30 minutes or so in the recovery room to allow the effects of the sedation to wear off and to be certain you have no adverse effects from the procedure. Some patients will feel some numbness or weakness in their legs for 45 minutes or so after the procedure, but this is temporary. After your recovery stay, a nurse will give you discharge instructions, and you will go home.

After the procedure, you don’t have to stay in bed but you should limit yourself to quiet “around the house” activities for the rest of the day. You should not drive for at least 6 hours after the procedure since the effects of the sedative may slow your reaction times. Most patients resume normal activities and return to work the day after their procedure.


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