Peripheral Nerve Root Block

A peripheral nerve root block (PNRB) is a diagnostic test your doctor performs to determine if a specific peripheral nerve is the source of pain. Depending on where you feel pain, your doctor may perform one or more diagnostic injections. If the PNRB reduces your pain and related symptoms, then that particular nerve or nerves are identified as a pain source.

Peripheral nerve root block…

  • Provides important diagnostic information
  • May relieve pain and symptoms

Anatomy pointer…

The peripheral nervous system (PNS) extends off from the central nervous system (CNS) (brain, spinal cord).  The PNS transmits information the CNS and organs and extremities (i.e., arms, legs).

What is peripheral pain?

Peripheral pain is different from typical neck or back pain.  Symptoms include pain, numbness, muscle weakness, and odd sensations like burning or tingling—and may be progressive or intense.  You may feel symptoms in one arm, both legs, or in a specific area in any part of your body.

Causes of peripheral pain include…

  • Diabetes, such as diabetic neuropathy (e.g., leg pain)
  • Complex regional pain syndrome (CRPS) (rare, chronic condition affecting the arms or legs)
  • Virus
  • Infection

Preparation for a PNRB

Your doctor reviews all the medications, vitamins and herbal supplements you take.  Certain drugs (e.g., blood thinners), such as NSAIDs (non-steroidal anti-inflammatory drugs) and supplements should be stopped several days before your procedure.  If you are taking an anti-inflammatory medication, your doctor may ask you to stop taking the NSAID, so he can accurately assess the effectiveness of the peripheral nerve root block and reduce the risk of bleeding.

Possible risks of a PNRB

All medical procedures are inherent for risk.  Rare but serious complications include bleeding, infection, nerve injury, headache, and allergic reaction to medication.  Other risks include increased pain or injection site tenderness.  Your doctor thoroughly discusses your personal risks with you before the procedure.

The Peripheral Nerve Root Block Procedure

A peripheral nerve root block is performed in a sterile setting, such as an operating room or ambulatory surgery center suite.  You change into a gown.  An intravenous line is started, and medication is administered through the IV to keep you comfortable.  You are awake so you can talk with the doctor during your procedure.  Rarely does the injection increase pain.

In the surgical suite, your body is positioned on the treatment table.  The skin area is cleansed using a sterile soap.  A local anesthetic is injected to numb the area.  A special imaging machine called a C-arm (fluoroscopy) is positioned to enable your doctor to view your spine during the procedure.  The needle is advanced around the nerve root sheath; a membrane that covers and protects each nerve root.  A small amount of contrast (dye) is injected to confirm needle placement and material flow.  Your doctor may ask you to describe what you feel.  Next, a local anesthetic and corticosteroid is injected into the area.  A corticosteroid is a slow-releasing and long-lasting anti-inflammatory medication that effectively reduces inflammation.  As the medication is injected, it flows around and coats local nerve roots.

After a peripheral nerve root block

The procedure takes about 15-minutes but may take longer if more than one injection is performed.  A small bandage covers the entry point of the needle.  You are moved into a recovery area and closely monitored before being discharged home with written aftercare instructions.  We call you the day after your procedure to follow up.

Outcome of a peripheral nerve root block

After a peripheral nerve root block, you may experience:

  • No pain relief
  • Pain relief lasting a few hours or days; then pain returns
  • Pain is relieved, returns for a short period of time, then improves

Keep a pain diary

You may experience some discomfort for a few days after the procedure. This is normal. We ask you to record your pain levels and other symptoms after the procedure. Your pain diary helps your doctor to fine-tune your treatment plan.

Learn more about the peripheral nerve root block procedure from these online sources:

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