What is a selective nerve root block?

Selective nerve root blocks can be used to diagnose and treat back pain that radiates into the arms or legs caused by an inflamed or compressed nerve root on either side of the spine. It can also be used to treat pain associated with herniated or ruptured disks. Selective nerve root blocks are outpatient procedures that take place in a pain clinic or doctor’s office. It involves the injection of a numbing medication into the space near the inflamed and painful nerve to cause relief of pain. A steroid may also be injected into this space to help decrease inflammation and pain. It is generally performed under fluoroscopy, or real-time x-ray with contrast dye, to ensure the medication is correctly administered.

Am I a candidate for selective nerve root block?

You are a candidate for a selective nerve root block if you have significant back pain that radiates into the limbs that has not improved with rest, ice/heat therapy, anti-inflammatory medications, or physical therapy. Pain caused by herniated and ruptured disks can be treated with selective nerve root blocks, also. You are not a candidate for a selective nerve root block if you are allergic to any of the medications used in the procedure (steroids, anesthetics, or contrast dye), if you have problems with bleeding or clotting, or have an infection of your blood or the skin near the injection site. Be sure to tell your doctor if you take blood thinners such as heparin, Coumadin, or aspirin. You will likely be told to stop taking those medications prior to the procedure, but never stop taking blood thinners without being instructed to do so by your provider. If you have uncontrolled diabetes or congestive heart failure, your condition may worsen with the injection of the steroids. Discuss the risks and benefits of this procedure with your provider.

How long will the selective nerve root block procedure take?

Selective nerve root blocks are relatively quick procedures. Once the injection site is cleaned, a small needle will be used to insert numbing medicine directly into your skin. After numbing your skin, your provider will insert a needle into the area next to your spine near the pain. A real-time x-ray machine is used to help guide the needle into the correct spot. Contrast dye is injected to help determine the proper location to inject the medication. An anesthetic like lidocaine is injected along with a steroid to help reduce inflammation. Lidocaine is the same drug used by dentists to numb your gum prior to filling a cavity. Following the injection, your provider will hold pressure to the site for a few minutes.

How long will it take to recover from selective nerve root block?

Recovery time is minimal for selective nerve root blocks. You will need to remain in the office under observation for fifteen following the procedure to ensure you tolerate the procedure. Some nerve weakness may be experienced following the procedure, but it should go away quickly. There are no activity restrictions. You should be able to return to work the following day. You may experience relief immediately following the procedure, but it may take up to 7 days to experience pain relief. However, it is likely you will have some soreness and bruising at the site; this is normal and will subside.



Wagner, A. (2014). Paraspinal injections – facet joint and nerve root blocks. Medscape. http://emedicine.medscape.com/article/1820854-overview#a1.