Facet Joint Injections and Nerve Root Blocks
A Selective Nerve Root Block or SNRB is a tool for diagnosis to find the particular source of nerve root pain. Alternatively, it is also used as a therapeutic technique to provide relief from lower back and leg pain.
The SNRB injection is composed of a combination of therapeutic steroids and local anesthetics and is inserted into the patient’s spinal nerve root myelin sheath. This acts to temporarily reduce pain and provide relief, at least for a short period of time. In many cases, this also helps in reducing inflammation around the throbbing area, which in turn makes it easier to identify where the pain was originating from.
The nerve is approached at it exits the forearm and injected with a steroid and lidocaine (anti-inflammatory and numbing agents respectively). Fluoroscopic X-Ray ensures the medicine reaches its target under the sheath. Instant reduction in pain positively identifies the nerve root as the pain source.
The patient stays awake for the whole procedure which usually takes about half an hour. Patients are injected twice: once with a contrast material for radiography (X-Ray Fluoroscopy), and the second time with the steroid-anesthetic combination.
The procedure will provide instant relief from pain temporarily before the pain returns. The steroids usually take about 3 days before they begin to be effective. Eventually, the pain will subside and benefits can last for weeks, even months.
If the procedure is successful in reducing the patient’s pain, it can be repeated multiple times to produce the same effect throughout the year. Typically, the procedure can be done up to three times in one year.
Very few risks are associated with the procedure. Sometimes the SNRB will worsen the patient’s pain, but that is attributed to the time allowed for steroids to take effect.