Peripheral Nerve Root Block (PNRB)

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The purpose of a peripheral nerve root block is diagnostic to determine if a specific peripheral nerve root is the potential source of neck or low back pain.  Besides the diagnostic benefits, some patients experience pain and symptom relief.

The procedure involves injecting a local anesthetic and corticosteroid into the nerve root sheath, a protective membrane (pia mater) covering each nerve root.  A corticosteroid is a powerful, slow-releasing, and long-lasting anti-inflammatory medication effective at reducing inflammation and pain.

About Peripheral Nerve Roots

The brain and the spinal cord make up the central nervous system (CNS).  The CNS extends to the peripheral nervous system (PNS).  The PNS is a system of nerves that branch beyond the brain, brain stem, and spinal cord.  The purpose of the peripheral nervous system is to carry information to and from the central nervous system.

Causes of Peripheral Pain and Other Symptoms

There are many types of peripheral nerve disorders.  Some of these disorders are caused by other diseases such as diabetes, a virus, or infection.  Complex regional pain syndrome (CRPS) is a rare but chronic problem that may affect the arms or legs.  Other disorders cause nerve compression such as a herniated disc or spinal stenosis. Some patients are born (congenital) with peripheral nerve problems.

Symptoms of a peripheral pain disorder may include pain, numbness, muscle weakness, and sensations such as burning or tingling.  Often, symptoms gradually worsen.

Patient Procedure Preparation

A PNRB is performed to help patients with moderate to severe pain. Patients are given instructions about medications to stop and when before the procedure.

The patient needs to make arrangements for someone to drive him/her home, as the patient is not allowed to drive for 24-hours.

Possible Risks and Complications

Potential complications include infection, low blood pressure, headache, injury to nerve tissue, and allergic reaction to medication. The physician provides complete information about the patient's potential risks and benefits.

What to Expect: The Procedure and After

During a peripheral nerve root block, the patient is awake to allow him/her to talk with the physician during the procedure. In the operating room (or sterile suite), cushions are positioned about the patient for support and comfort.  The physician is given good access to the appropriate spinal level (e.g., neck, low back).  The injection site is cleaned using a sterile solution. A local anesthetic is injected and given time to take effect.

A fluoroscope C-arm (named for its characteristic C-shape) is positioned over the patient. The fluoroscope provides a series of real-time x-rays projected on monitors in the operating room to assist the physician precisely place the needle.  A small amount of contrast (dye) is injected to ensure correct spread; this is confirmed by fluoroscopy. Next, a low volume anesthetic and steroid solution is injected.  Rarely does pain increase during the injection. After the injection, the injection site is bandaged.

Typically, a peripheral nerve root block involves injections into two or more spinal levels. Procedures take about 15- to 20-minutes. After the procedure, patient is wheeled into the recovery area, wherea nurse monitors vital signs. When the patient is ready to be discharged, written instructions for home care are provided.

Results

• After a  peripheral nerve root block, patients experience one of three results:
• No pain relief
• Pain is relieved for a few hours, or days, and returns
• Pain is relieved, returns for a short time period, and improves

The physician's office follows up with the patient by phone 24- to 48-hours after the procedure.  Patients can report their pain levels and symptoms in the days following the injection, with particular attention paid to where the pain (if any) occurs in relation to the injection site(s).

Conclusion

Peripheral nerve root blocks have provided considerable pain relief to many carefully selected patients with moderate to severe back or neck pain.