Serenity

What is a diagnostic selective nerve root block (diagnostic SNRB)?
A diagnostic SNRB is the injection of a local anesthetic medication into the epidural space, targeting one or two specific levels/nerve roots.
 

What is the purpose of a diagnostic SNRB?
Pathologic changes of the spine can often lead to inflammation of the surrounds structures: bones, discs, ligaments, muscles and nerves. Diagnostic SNRBs are important diagnostic procedures to identify the underlying cause of pain and the primary levels involved. This information will confirm that treatment at the specific nerve level may help with your pain. It will also confirm where the steroid should be injected or surgery performed in order to produce the best results. The diagnostic SNRB itself does not produce any long-term benefit. It is only a test and is expected to alleviate pain for a few hours, at the most. A good, short-term response, however, will allow your doctor to proceed with appropriate treatment in order to produce long-term pain relief.

How is the procedure performed?
You will be placed on the procedure table. The injection site is sterilized with either iodine or
chlorhexidine. The site to be injected is numbed with a local anesthetic, and a needle is directed to the target area. X-ray guidance is used to ensure proper placement and positioning of the needle. Contrast (x-ray dye) may be injected to be sure the needle is in the proper position. Once proper needle placement is confirmed, the local anesthetic solution is slowly injected. The procedure may be repeated at each targeted level/nerve root.

Will the procedure be painful?
The injection can be painful but local anesthetic will b used to reduce the pain from the injection as much as possible. Because of the diagnostic purpose of the procedure it is important to reduce any other factors (pain medications/sedation) which could distort the results.

​

What are the discharge instructions?
As the local anesthetic used during the procedure can cause motor weakness, we recommend that you do not drive or operate machinery for at least 24 hours after the procedure. You may return to work the next day following your procedure. You may resume your normal diet immediately. Do not engage in any strenuous activity for 24 hours. Do not take a bath,
swim, or use a hot tub for 24 hours (you may take a shower). Call the office if you have any of the
following: severe pain afterwards (different than your usual symptoms), redness/ swelling/ discharge at the injection site(s), or fevers/chills.
 

What are the risks and side effects?
The complication rate for this procedure is very low. Whenever a needle enters the skin, bleeding or infection can occur. Some other serious but extremely rare risks include paralysis and death.
You may have an allergic reaction to any of the medications used. If you have a known allergy to any medications, especially x-ray contrast dye or local anesthetics, notify our staff before the procedure takes place.

You may experience any of the following side effects up to 4 hours after the procedure:
● Arm/Leg muscle weakness or numbness may occur due to the local anesthetic affecting the nerves that control your arm/leg (this is a temporary affect and it is not paralysis). Your arm/leg strength will return slowly and completely.
● Dizziness may occur due to a decrease in your blood pressure. If this occurs, remain in a seated
or lying position. Gradually sit up, and then stand after at least 10 minutes of sitting.
● Mild headaches may occur. Drink fluids and take pain medications if needed. If the headaches
persist or become severe, call the office.
● Mild discomfort at the injection site can occur. This typically lasts for a few hours but can persist
for a couple days. If this occurs, take anti-inflammatories or pain medications, apply ice to the
area the day of the procedure. If it persists, apply moist heat in the day(s) following.
 

The side effects listed above can be normal. They are not dangerous and will resolve on their own. If, however, you experience any of the following, a complication may have occurred and you should either contact your doctor. If he is not readily available, then you should proceed to the closest urgent care center for evaluation:
● Severe or progressive pain at the injection site(s)
● Arm or leg weakness that progressively worsens or persists for longer than 8 hours
● Severe or progressive redness, swelling, or discharge from the injections site(s)
● Fevers, chills, nausea, or vomiting
● Bowel or bladder dysfunction (i.e. inability to urinate or pass stool or difficulty controlling either)
 

How long does it take for the procedure to work?
The effect of the diagnostic SNRB should be felt within 15-30 minutes. Remember, however, that it may last as little as 60 minutes. It is a diagnostic test only and is not meant to provide long-term benefit. During the duration of effect, the targeted pain should improve by at least 50-75%. If the test is successful, then your doctor can arrange for you to receive a steroid injection in the same area.

Steroid medication is a powerful anti-inflammatory medication. An injection of steroid can
substantially decrease this inflammation and thereby lead to a significant reduction in pain.