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Selective Nerve Root Block

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What is a selective nerve root block?

A selective nerve root block is an injection of a local anesthetic along a specific nerve root. Along the spine, there are several “holes” or “foramina” through which nerve roots emerge. If these foramina are partially closed from bulging disks, bone spurs, misalignment of vertebrae, etc., the nerve root can also be pinched. This typically causes a shooting or radiating pain along that nerve root. In a selective nerve root block, a small needle is placed in the foramen alongside the nerve root and the medication is injected.

Why is it done?

When the nerves in the foramina are irritated or pinched by a bulging disk, narrowed “nerve canal” or bone spur, the resulting inflammation can cause pain, numbness, or tingling. The local anesthetic can reduce reduce the pain and other symptoms which may provide diagnostic information to your doctor.

How long does it take to do?

The actual injection takes only a few minutes. Please allow about an hour for the procedure; this will include talking to your doctor before the procedure, signing the informed consent, positioning in the room, and observation by the recovery room nurse afterwards.

What medicines are injected?

The injection consists of  local anesthetic (e.g., Bupivacaine).

Will it hurt?

All of our procedures begin by injecting a small amount of local anesthetic through a very small needle. It feels like a little pinch and then a slight burning as the local anesthetic starts numbing the skin. After the skin is numb, the procedure needle feels like a bit of pressure at the injection site. If you experience any pain during the procedure, your doctor will inject more local anesthetic as needed. The actual placement of the needle is not painful. However, keep in mind the nerve root is pinched and irritated. If the needle tip brushes against the nerve during placement, you may feel a “zing” down the nerve root, similar to striking your “funny bone”. During the injection of the local anesthetic, there may be a temporary achiness along the nerve root until the local anesthetic sets in, usually in about 15 seconds. These sensations are normal.

Will I “be asleep” for this procedure?

This choice is yours. You can choose to have the procedure done under local anesthetic only. You can also choose to have IV sedation, which can keep you very comfortable. It can range from some drowsiness or you may have little or no memory of the procedure depending upon your comfort level, regardless of the amount of sedation, you must not eat or drink anything for 6 hours prior to this and you must also have a driver when choosing sedation. It is OK to take your medications with a sip of water with either decision.

How is it done?

It is typically done with you lying on your stomach for back injections and on your side for neck injections. Your blood pressure and oxygenation will be monitored. In addition to your doctor and the x-ray technician, there will be a nurse in the room at all times if you have any questions or discomfort during the procedure. The skin on the back or neck is cleaned with antiseptic solution and then the procedure is done.

What should I expect after the injection?

Immediately after the injection, you may feel your legs or arms, along that specific nerve root, becoming slightly heavy or numb. You may notice that your pain may be gone or considerably less. This is due to the effect of the local anesthetic and lasts only for a few hours. Your pain may return and you may have some soreness at the injection site for a day or so.

What should I do after the procedure?

We advise the patients to take it easy for a day or so after the procedure. Perform the activities as tolerated by you. Your recovery room nurse will advise you about applying ice to the site.

Can I go back to work the same day or the next day?

You should be able to unless the procedure was complicated. Your doctor or recovery room nurse will discuss this with you.

How long does it last?

 The immediate effect is from the local anesthetic injected. This wears off in a few hours.

What are the risks and side effects?

Overall, this procedure has very few risks. However, as with any procedure, there are some risks and side effects you should know about. Commonly encountered side effects are increased pain from the injection (usually temporary), rarely inadvertent puncture of the “sack” containing spinal fluid (may cause headaches), infection, bleeding, nerve damage, or no relief from your usual pain.

Who should not have this injection?

The following patients should not have this injection: if you are allergic to any of the medications to be injected, if you are on a blood-thinning medication (e.g. Coumadin, injectable Heparin), or if you have an active infection going on. With blood thinners like Coumadin, your doctor may advise you to stop this for 4-7 days beforehand or take “bridge therapy” with Lovenox prior to the procedures. Anti-platelet drugs like Plavix may have to be stopped for 5-10 days prior to the procedure.

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