A nerve root block is an injection into the sheath surrounding a nerve root in the spine to decrease your pain temporarily and to define it more precisely. The exam uses therapeutic steroid and local anesthetic (numbing medication) to decrease pain and inflammation. Pain relief from the procedure varies from minimal to long-term, depending on the specific symptoms.

You must have symptoms present for this procedure to be effective. If you are not experiencing symptoms prior to your procedure, please cancel your appointment and reschedule the exam once your symptoms have returned.

During the procedure—what to expect

• You will remain awake throughout the procedure.
• An anesthesiologist will use a thin needle to place anesthetic and steroid (anti-inflammatory medication) into the nerve sheath. (There may be some discomfort from the needle, but, for most people, this is minor.)
• The anesthesiologist checks the needle position using X-ray guidance (fluoroscopy).
• Contrast material is placed into the nerve sheath to document the needle position and X-rays are taken.
• During the injection, you may feel pressure or pain. The anesthesiologist will want to know how this discomfort compares to your usual pain symptoms.

After the procedure—what to expect

• Initially, you may experience numbness and/or relief from your symptoms for up to six hours after the injection.
• When the anesthetic wears off, your usual symptoms may return. The steroids usually require three to five days to provide pain relief.
• If there is no change in your pain symptoms after a week, your doctor may want to investigate other possible sources for your pain.

Possible side effects

• Steroid medications may cause facial flushing, occasional low-grade fevers, hiccups, insomnia, headaches, water retention, increased appetite, increased heart rate, and abdominal cramping or bloating.
• These side effects occur in only about 5 percent of patients and commonly disappear within one to three days after the injection.