What Are Selective Nerve Root Blocks?

A selective nerve root block is a minimally invasive procedure that is used to diagnose and treat cervical, thoracic, and lumbar pain, and associated extremity pain. It involves injecting a local anesthetic directly into a specific, targeted nerve root of the spine to help identify the source of a patient’s pain symptoms. Secondarily, it may also be used to provide therapeutic relief of a patient’s symptoms.

When a spinal nerve root becomes irritated, inflamed, or compressed it can cause spinal pain. Furthermore, symptoms may be felt in the upper or lower extremities depending on where the irritated nerves are located. For example, cervical spine nerve irritation may lead to pain, numbness, and tingling in the neck, shoulders, or arms. Whereas thoracic spine nerve irritation can result in pain in the upper back or pain along the chest wall and ribs. Lastly, lumbar spine nerve irritation may result in pain, numbness, and tingling in the low back, hips, buttocks, and legs.

The source of a patient’s pain may be difficult to identify. At times, imaging of the affected area, utilizing magnetic resonance imaging (MRI), may not show which nerve is causing the pain. In these cases, a selective nerve root block may be used to isolate the nerve root that is the source of a patient’s pain. In addition to its’ diagnostic ability, a selective nerve root block can also be used to provide effective pain relief of various conditions.

A selective nerve block involves injecting a local anesthetic, often combined with a corticosteroid, into the targeted nerve root. The local anesthetic essentially numbs the nerve, while the steroid helps to decrease inflammation and associated pain. A selective nerve root block is similar to an epidural injection; however, the medication is directed at the offending nerve root and not into the epidural space. The success rate of selective nerve root blocks varies among individuals, as some nerve roots are very difficult to treat due to their location and surrounding structures.

How Are Selective Nerve Root Blocks Performed?

Pain-Doctor-Interscalene-Nerve-Block-Injection-Procedure-5A selective nerve root block procedure is a minimally invasive technique that is performed in an outpatient setting. Typically, the procedure takes between 30 and 60 minutes to complete.

A selective nerve root block procedure is usually performed with the patient lying in a prone position under a fluoroscopic X-ray. The skin of the affected area is cleaned with an antiseptic solution and is then numbed with a local anesthetic. A needle is then inserted, using fluoroscopic guidance, into the proper position within the spine. A small amount of contrast dye is injected to confirm proper needle placement.

The final needle position for a selective nerve root block is just superior to the targeted nerve root through the foramen (which is the space between the vertebral bodies). The injection, which usually consists of a local anesthetic such as lidocaine and a steroid such as dexamethasone, is injected into the affected area. Once the injection is complete, the patient is monitored for adverse reactions. If the patient’s pain subsides after the injection, it is presumed that the pain-generating nerve root has been identified.

Most patients resume normal activities the day after the injection procedure. Many patients may report an immediate relief of symptoms that is due to the injection of the local anesthetic, which may be followed by a slight increase in pain until the cortisone begins to exert its effects.

The relief of symptoms from a selective nerve root block varies among patients and can last from several days to several months.

Following a selective nerve root block, patients may experience increased pain at the injection site, increased radicular pain, lightheadedness, increased spinal pain, nausea, headache, and vomiting.

Risks associated with selective nerve root blocks are rare, but may include: infection, bleeding, and allergic reaction to the medications used during the procedure. Additionally, serious rare complications include: membrane perforation of the dura, nerve damage, and paralysis.

Conditions Related To Selective Nerve Root Blocks

herniated discConditions that are commonly treated with selective nerve root blocks include:

  • Cervical radiculopathy: Pain and/or altered sensation that progresses into the upper extremities
  • Lumbar radiculopathy: Pain and/or altered sensation that progresses into the lower extremities
  • Failed back surgery syndrome: Spinal pain that persists or develops following spinal surgery
  • Spinal stenosis: Narrowing of the spinal canal
  • Bulging intervertebral discs: Decreased structural integrity of the intervertebral discs outer layer, resulting in a bulge from the disc’s normal position
  • Herniated disc: Rupture of the nucleus pulposus of an intervertebral disc through a tear in the outer layer of the disc
  • Arthritis: Degeneration of the spinal joint cartilage

Conclusion

A selective nerve root block is a minimally invasive procedure that can effectively diagnose and treat many conditions that result from spinal nerve root irritation and inflammation. Selective nerve root block procedures are considered a very safe and effective treatment option for many chronic pain conditions including radiculopathy, failed back surgery syndrome, spinal stenosis, bulging and herniated discs, spinal stenosis, and arthritis.

A selective nerve root block targets the offending spinal nerve root by injecting a local anesthetic, often combined with a steroid. This combination of medication allows for pain relief as well as relief of inflammation that may be contributing to a patient’s pain. Symptom relief can last anywhere from several days to several months and the procedure can be repeated, if necessary. Patients suffering with chronic pain conditions should speak with their physicians about the potential of using selective nerve block to diagnose, and possibly treat their pain symptoms.

References

  1. org. Selective Nerve Root Blocks – Baxter Regional Medical Center. N.p. Web. 21 Mar.2015.
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  3. Huston CW, Slipman CW, Garvin C. Complications and side effects of cervical and lumbosacral selective nerve root injections. Arch Phys Med Rehabil. 2005;86(2):277-283.
  4. Khan KS, SAH S, Rafiq T, Dolan M, Devitt AT. The role of selective nerve root block in patients with lumbar radiculopathy. J Bone Joint Surg Br. 2004;86-B(sup II):123.
  5. Riew KD, Park JB, Cho YS, Gilula L, et al. Nerve root blocks in the treatment of lumbar radicular pain: a minimum five-year follow-up. Journal of Bone and Joint Surgery. 2006;88(8):1722-1725.