Epidural - Padda Institute Center for Interventional Pain Management

Selective nerve root block (cervical, thoracic or lumbar)


Nerve roots exit your spinal cord and form nerves that travel into your arms or legs. These nerves allow you to move your arms, chest wall, and legs. These nerve roots may become inflamed and painful due to irritation, for example, from a damaged disc or a bony spur.

A selective nerve root block provides important information to your physician and is not a primary treatment. It serves to prove which nerve is causing your pain by placing temporary numbing medicine over the nerve root of concern. If your main pain improves after the injection then that nerve is most likely causing your pain. If your pain remains unchanged, that nerve probably is not the cause of pain.

 

By confirming or denying your exact source of pain, it provides information allowing for proper treatment, which may include additional nerve blocks and/or surgery at a specific level.  Selective nerve root blocks are similar to epidurals, but instead of putting medication in to cover all of the nerve roots, selective blocks are done so as to cover just one or two nerve roots.

The membrane that covers the spinal cord and nerve roots in your spine is called the dura membrane. The space surrounding the dura is the epidural space. Nerves travel through the epidural space before they form the nerves that travel down your arms, along your ribs and into your legs. These nerve roots may become inflamed, for example, due to irritation from a damaged disc or contact with the bony structure of the spine. A selective epidural injection places anti-inflammatory medicine over the nerve root and into the epidural space to decrease inflammation of the nerve roots therefore reducing your pain. The epidural injection may assist the injury to heal by reducing inflammation. It may provide permanent relief or provide a period of pain relief for several months while the injury/cause of your pain is healing.

The selective nerve root block (SNRB) is a procedure that anesthetizes an individual nerve root, either within the neck (‘cervical’), or in the back (‘thoracic’ or ‘lumbar’), thought to be responsible for the patient’s pain. The nerve root sheath is injected and anesthetized with the intent of relieving this pain.  This procedure is sometimes referred to as a ‘Foraminal Block.’  The SNRB procedure delivers a low volume of concentrated medication directly into the affected nerve root sleeve.

Back Pain is often multifactorial and difficult to diagnose because the symptoms overlap considerably with those of other degenerative disorders of the spine.  The SNRB is useful in both the diagnosis and the treatment of back pain; therefore, it is both a diagnostic as well as a therapeutic procedure. In other words, if we inject a medication within the suspected nerve root sleeve and the pain improves, we are fairly confident that this nerve root is responsible for the pain; conversely, if we inject a medication and the pain is no better, this implies that this nerve root is likely not responsible for the pain.

 

Nerve Root Impingement

Patients with pain from nerve root irritation often have an anatomic cause, which is usually the result of a nearby structure pushing on, or impinging on the nerve, causing irritation of that nerve.

The most common causes of this are either a disc abnormality or an adjacent bone spur, either of which, when in close proximity to the nerve, can irritate it and cause pain in the distribution of that nerve.

 

Radicular Pain

If there is irritation of a nerve in the back or neck, it may cause symptoms of pain, and usually this pain is in the distribution of that particular nerve, referred to as radicular pain.

Dermatomes

 

Patient Selection

SNRB is most effectively used in patients with radicular pain.

These patients should have recent imaging studies (CT or MRI scan), which in many instances help to identify the cause of pain. Not all patients will have an identifiable cause for the pain on imaging, but all should have radicular symptoms.  Electrodiagnostic studies such as EMG are useful in distinguishing peripheral neuropathy, entrapment and radiculopathy.

 

Procedure

The procedure is explained to the patient, questions are answered and informed consent is obtained.

The patient is placed prone (stomach down) for lumbar or thoracic injections, or supine (face up) for cervical injection on the fluoroscopic table, and the area is sterilely cleansed with povidone-iodine (Betadine) and alcohol.

The exact level is located with the fluoroscope, and the skin overlying this area is anesthetized (numbed) with lidocaine. This is either to the right or left of midline on the back.

A needle is sterilely advanced along the nerve root sleeve, which typically elicits a mild degree of radicular pain in the distribution of that nerve. It is important for us to know whether the pain elicited is similar to the patient’s pain (concordant response), or dissimilar (discordant response).

Typically, as small amount of water-soluble contrast (dye) is injected to confirm proper needle tip position.

Once this is confirmed, a mixture of anesthetic (lidocaine or bupivacaine) and anti-inflammatory medication (steroid) is injected.

The needle is slowly withdrawn

This procedure may be performed with either CT or Fluoroscopic guidance.

 

 

What will happen after the procedure?

Immediately after the procedure, you will get up and walk around and try to imitate something that would normally bring about your usual pain. You will then report the percentage of pain relief and record the relief you experience during the next week. We ask that you remain at the Clinic until you feel you are ready to leave.

You may not be able to drive the day of your procedure. Your legs or arms may feel weak or numb for a few hours. You may be referred to a physical therapist immediately afterwards while the numbing medicine is still working. If the doctor prescribes physical therapy, it is very important that you continue with the physical therapy program.

Although you may feel much better immediately after the injection (due to the numbing medicine), there is a possibility your pain may return within a few hours. It may take a few days for the steroid medication to start working.

You may experience some weakness and/or numbness in your legs a few hours after the procedure. If so, do not engage in any activities that require lifting, balance and coordination.

Drink plenty of clear liquids after the procedure to help remove the dye from the kidneys.

 

 

General Pre/Post Instructions:

You should eat a light meal within a few hours before your procedure. If you are an insulin dependent diabetic, do not change your normal eating pattern prior to the procedure. Please take your routine medications (i.e. high blood pressure and diabetic medications).  Do not take pain medications or anti-inflammatory medications the day of your procedure. You need to be hurting prior to this procedure. Please do not take any medications that may give you pain relief. These medications can be restarted after the procedure if they are needed. If you are on Coumadin, Heparin, Plavix or any other blood thinners (including Aspirin), or the diabetic medication Glucophage you must notify this office so the timing of these medications can be explained. You will either be at our clinic facility for approximately 1-3 hours for your procedure. You may need to bring a driver with you. You may return to your normal activities the day after the procedure, including returning to work.

 

Risks of nerve root injection?

Increased localized back pain, neck pain, arm pain or leg pain can be expected from several days to several weeks and rarely several months. There is a rare risk of permanent injury to nerve tissue with weakness or loss of sensation.  There is also a rare risk of complication from anesthesia used to make you feel more comfortable during the procedure.

As with any procedure, there is a risk of significant complications. The most common side effects from the nerve root block can include (but are not limited to):

  • Allergic reactions to medications
  • Infection (occurs in less than 1 per 15,000 injections)
  • Post-injection flare (nerve root irritation with pain several hours after treatment, which may last days or weeks)
  • Depigmentation (a whitening of the skin)
  • Local fat atrophy (thinning of the skin)
  • Destruction of a motor or sensory nerve in the path of the needle
  • Bleeding, nerve injury, organ injury and death are rare but possible

 

 

Epidural Steroid Injection (ESI)

Back pain affects nearly everyone at some point in their adult life. Often times the exact cause of pain is not readily apparent, as there are many factors which may  contribute to a patient’s back pain, including disc disease, referred pain, as well as psychological factors. This can make the exact site and level responsible for the back pain more challenging to localize and diagnose. Unfortunately, while imaging studies (X-RAYs, MRI and CT scans) are helpful in screening the spine for potential causes of back pain, sometimes they don’t demonstrate an exact cause for a patient’s pain.
Back pain may arise from any anatomic structure within or around the spine which has nerve endings and is capable of transmitting pain. These structures include discs, facet joints, muscle, nerves, ligaments and dura (the membrane lining of spinal canal). All of these structures are either directly touching or in close proximity to the epidural space. Pain may be either within the spine itself (‘axial’), or radiating from the spine (‘radicular’). Both of these types of pain are ideally alleviated with the ESI.

The Epidural Injection (ESI) is a procedure that anesthetizes the space around the spinal sac (dural sac).  This procedure may be performed at any level of the spine, although is most commonly performed in the lumbar spine or cervical spine.  As opposed to a selective nerve root block, or a facet injection, which target a specific nerve or joint on one side of the spine, the ESI treats several consecutive levels on both sides of the spine.  The ESI procedure delivers a low volume of concentrated medication directly into a portion of the epidural space.  The ESI typically covers the epidural space of about 3 vertebral body levels.

What is the epidural space?
The membrane that covers the spinal cord and nerve roots in your spine is called the dura membrane. The space surrounding the dura is the epidural space. Nerves travel through the epidural space to your back and into your legs. Inflammation of these nerve roots may cause pain in these regions due to irritation from a damaged disc or from contact in some way with the bony structure of the spine.

What is an epidural and why is it helpful?
An epidural injection places anti-inflammatory medicine into the epidural space to decrease inflammation of the nerve roots, hopefully reducing the pain in your back or legs. The epidural injection may help the injury to heal by reducing inflammation. It may provide permanent relief or provide a period of pain relief for several months while the injury/cause of your pain is healing. Depending on the location of your pain, the epidural steroid injection can be given in the neck (cervical), middle back (thoracic) or lower back (lumbar).
What will happen to me during the procedure?
An IV may be started so that relaxation medication can be given. You will be placed lying on your stomach on the x-ray table and positioned in such a way that your doctor can best visualize your back using x-ray guidance. The skin on your back will be scrubbed using 2 types of sterile scrub (soap). Next, the physician will numb a small area of skin on your low back with numbing medicine. This medicine stings for several seconds. After the numbing medicine has been given time to be effective, your doctor will direct a small needle using x-ray guidance into the tiny bony opening (sacral hiatus) just above the crease in your buttocks. A small amount of contrast (dye) is then injected to insure proper needle position in the epidural space. If the medicine does not travel high enough to reach the affected area, a small catheter will be placed into the epidural space and advance up to the area of abnormality. Then, a mixture of numbing medicine (anesthetic) and anti-inflammatory (cortisone/steroid) will be injected.
What will happen after the procedure?
You will go back to a recovery area or may be recovered in the procedure room where you will be monitored for 15-30 minutes. You will then record the relief you experience during the next week.  You will also be given a follow-up appointment for a repeat block if indicated. These injections are usually done in a series of three(3), about one to three weeks apart. You may not be able to drive the day of your procedure. Your legs may feel weak or numb for a few hours, but your weakness should quickly resolve.  If it does not, please go to the nearest ER.
General Pre/Post Instructions
You should eat a light meal within a few hours before your procedure. If you are an insulin dependent diabetic, do not change your normal eating pattern prior to the procedure. Please take your routine medications (i.e. high blood pressure and diabetic medications). If you are on Coumadin, Heparin, Plavix or any other blood thinners (including Aspirin), or the diabetic medication Glucophage you must notify this office so the timing of these medications can be explained. You may need to bring a driver with you. You may return to your normal activities the day after the procedure, including returning to work. Drink plenty of clear liquids after the procedure to help remove the dye from the kidneys.
The discomfort generated during the epidural procedure may take several days to subside, and your physician may prescribe pain medication.  During the healing process it is important to treat your back with care. Your physician will provide you with activity and physical rehabilitation guidelines.  You will be required to do a special physical therapy and rehabilitation program for several weeks after your procedure.  A special back support may be necessary as well as electrical stimulation to lessen spasms.  You should be able to resume regular activity four hours after your procedure.  You may have to undergo a nerve conduction study and EMG to help determine the severity and duration of back injury.
You may experience an increase in your usual pain including muscle soreness in your back where the needles were inserted. Use ice packs three or four times a day and take your usual pain medications. Do not apply heat or soak in water (i.e. tub, pool, jacuzzi, etc.) for the remainder of the day.
Duration of Relief
Most patients will have 2-3 months of relief of some of their complaints. This can range from no relief to near absolute relief with the duration being from days to many months. Some patients may not get any relief with the first injection but after one or two more done over the following weeks. Many physicians will do these injections in cycles (series) where they will do one, two or three epidural injections over a couple of weeks. The interval between these cycles should be somewhere between two to three months. More frequent administration of steroids could lead to more serious side effects. Transforaminal epidural steroid injection series will often last for 4-6 months or even longer.