What is a Selective Nerve Root Block and how does it control my pain?
- A selective nerve root block is when a local anesthetic – usually Bupivacaine – and a steroid medication is injected along
a specific nerve root. This is usually done when the nerves in the foramina (the “holes” along the spine) are pinched or
irritated due to a bone spur, a narrowed “nerve canal,” a bulging disk, etc. The resulting inflammation from these
conditions can cause pain, tingling, or numbness. The implementation of an anti-inflammatory steroid can reduce pain
and other symptoms, while providing the diagnostic information to the doctor.
What should I expect during the procedure?
- The doctor will begin by injecting a small amount of a local anesthetic through a needle; this will feel like a little pinch,
followed by a slightly burning sensation as the skin begins to get numbed. After the skin is numbed, the needle that is
used for the procedure feels as like pressure is applied on to the skin. The actual placement of the needle should not be
very painful; however, considering that the nerve root is irritated and pinched, you may feel a “zing” along the nerve
root (like what you feel when you injure your funny bone). There may also be an ache along the nerve root until the
local anesthetic sets in.
What are the risks and side effects?
- A selective nerve block has very few risks associated with it; however, some common ones are
- Increased pain from the injection (usually temporary)
- Puncture of the “sack” which contains the spinal fluid; this may cause headaches, but it is extremely rare
- Nerve damage
- Infections at the site at which the needle enters the skin
- No relief from the pain
- Allergic reactions can occur to any of the medications used. If you have a known allergy to any medications, especially x-
ray contrast dye or local anesthetics, please notify our staff before the procedure takes place. Individuals who are on
blood thinning medication or have active infections are advised to delay having a selective nerve root block until their
medical condition is improved, or until they have discussed it with a doctor.
How long does it take for the procedure to work?
- Immediately after the procedure, individuals may feel their legs or arms become slightly heavy or numb; this temporary
effect is normal. Any immediate relief that occurs is from the local anesthetic that was injected, and it will wear off in a
few hours. The injected steroid begins to work in around 2-3 days after the procedure and its effect can last between
several days to a few months. Most individuals typically need between 2-3 injections, spaced approximately one week
apart, to notice gradual improvement in pain and relief. However, the number of injections you will need are dependent
on how you respond to the first injection. Keep in mind that this injection may work very well for pain in certain areas
but not other areas; areas of pain that do not respond may need other treatments, which you can discuss with your