Selective Nerve Root Block​

 

Selective nerve root blocks (SNRBs) are similar to epidural steroid injections. A small amount of a medication mixture, usually a combination of a steroid and a numbing agent such as lidocaine, is injected at the nerve root where the problem is suspected to be. The patient then reports feedback on if their symptoms do or do not improve. 

 

Why is it performed?

 

A SNRB is typically performed to help confirm a suspected problematic area of the spine.

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What happens during the procedure?

 

You will be brought to an x-ray table where you will lay on your stomach.  IV sedation may be given if you elect to have it.  The overlying skin is then prepped as a sterile field.  The fluoroscopy unit (x-ray machine) is used to identify the area of interest.  Then local anesthesia is used to numb the skin. The fluoroscopy unit is then used to safely guide the needle to the correct location.

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How long does the process take?

 

The surgery center usually asks for you to arrive one hour before the scheduled procedure. The actual for approximately 2 hours. You will arrive one hour before the procedure. The actual procedure time is usually fifteen minutes. The remainder of the time will be spent in the recovery room.

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Is the procedure painful?

 

The procedure does involve an injection so you may feel some discomfort. Local anesthetic is used, and intravenous medication may be given to make you as comfortable as possible. You may feel some warmth as the fluid is injected. You may also experience some of your typical pain. The doctor will be interested in how this compares to your usual symptoms.

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When will the pain relief take effect?

 

You may experience numbness and/or relief from your typical pain for up to 6 hours after the injection. This is due to the long-acting anesthetic injected. Your usual symptoms may then return and may possibly be worse than usual for a day or two. The beneficial effects of the steroid injection usually begin in 2 to 3 days or may take as long as a week.

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Will I need further injections?

 

It is hard to determine exactly. If an initial injection provided a certain amount of pain relief, a second injection may provide additional benefit. If your pain subsides completely and does return at some point, additional injections may be an option.

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What are the risks of this procedure?

 

Generally speaking, this procedure is very safe. However, as with any procedure, there are risks, side effects, and the possibility of complications. The most common side effect is pain, which is temporary. There is also occasional bruising. There is a slight possibility of infection, either at the site of injection or in the deeper tissue. This could require the use of antibiotics, either by mouth or intravenously. Additionally, if the infection were severe, it could require hospitalization and further surgery.

 

In these procedures it is possible to get close to a nerve root, and this would cause a slight increase in pain with possible radiation into the limb. It is very unlikely, but there could be permanent nerve damage.

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Very rare complications may include bone injury from repetitive steroid intake, reaction to the injectant (anesthetic or steroid material) causing respiratory or cardiac compromise as well as seizures. Death is even a possibility, as with any invasive procedure, although this possibility is exceedingly rare.

Steroid medications have rarely been associated with hip or arm (bone) damage, and this has usually been with high doses or prolonged use. This remains a rare complication.

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