Selective Nerve Root Block (SNRB)
A selective nerve root block (SNRB), is primarily used to diagnose the specific source of nerve root pain and, secondarily, for therapeutic relief of low back pain and/or leg pain
When a nerve root becomes compressed and inflamed, it can produce back and/or leg pain. In the instance that an imaging study (e.g. MRI) may not clearly show which nerve is causing the pain and an SNRB injection is performed to assist in isolating the source of pain. In addition to its diagnostic function, this type of injection for pain management can also be used as a treatment for a far lateral disc herniation, in which a disc that ruptures outside the spinal canal
In an SNRB, the nerve is approached at the level where it exits the foramen, the hole between the vertebral bodies. The injection is done both with a steroid medication and lidocaine, which serves to numb the area. Fluoroscopic imaging is used to ensure the medication is delivered to the correct location. If the pain goes away after the injection, it can be inferred that the back pain generator is the specific nerve root that has just been injected. Following the injection, the steroid also helps reduce inflammation around the nerve root.
How long does it take?
The actual injection takes only a few minutes. However, Please allow about 45 minutes for the entire procedure.
What should I do after the procedure?
We advise that patients take it easy for a day or so after the procedure. Perform only those activities that are easily tolerated by you.
What are the expected results?
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. True pain relief will come 1-2 days post procedure.