What Is a Nerve Block?
A nerve block is a procedure that disrupts specific nerve activity. It can help diagnose or treat certain types of neuropathic pain, or pain caused by nerve dysfunction or damage. Nerve blocks may be performed by injecting chemicals or anesthetics to the area, or by deliberately cutting or damaging certain parts of the nerve. You may have even had a nerve block without knowing it: Dentists commonly use nerve-blocking agents such as novocain to numb your mouth during potentially painful procedures.
Why You Might Have a Nerve Block
If your doctor is trying to diagnose a chronic pain condition caused by nerve dysfunction, he may use a nerve block to pinpoint the exact problem area. In addition to a nerve block, he may also perform an electromyography (EMG) and/or a nerve conduction velocity (NCV) test to narrow down the exact cause of your chronic nerve pain.
Nerve blocks can also treat chronic neuropathic pain, such as that caused by nerve damage or compression. They are regularly used to treat back and neck pain caused by herniated discs or spinal stenosis. Nerve blocks may be used to control pain temporarily or permanently, depending on the procedure used.
Common Types of Nerve Blocks
- A local nerve block is performed by injecting or applying local anesthetics, such as lidocaine, to a certain area. An epidural is a local nerve block that involves injecting steroids or analgesics into the area that surrounds the spinal cord. Though common during childbirth, an epidural may be also be used to treat chronic neck or back pain caused by a compressed spinal nerve. Local nerve blocks are usually temporary, though some may be repeated over time.
- A neurolytic block uses certain chemicals, such as alcohol or phenol, or thermal agents, such as cryogenic freezing, to treat chronic nerve pain. These procedures actually cause damage to certain areas of the nerve pathway. This means a neurolytic block is usually appropriate only in severe chronic pain cases, such as cancer pain or complex regional pain syndrome (CRPS).
- A surgical nerve block is performed by a neurosurgeon, and involves surgically removing or selectively damaging certain areas of the nerve. Like a neurolytic block, a surgical nerve block is usually reserved for severe pain cases, such as cancer pain or trigeminal neuralgia. Most surgical nerve blocks are permanent.
Risks Associated with Nerve Blocks
Even a temporary nerve block such as an epidural carries a risk of permanent nerve damage. Because nerves are extremely sensitive and regenerate slowly, even a tiny error in calculation can cause devastating side effects. These include muscle paralysis, weakness or lasting numbness. In some rare cases, nerve blocks may actually irritate the nerve further, causing an increase in pain.
Fortunately, these delicate procedures are performed by skilled and licensed health practitioners. These include dentists, surgeons and anesthesiologists. While there is always a risk of nerve damage during these procedures, most nerve blocks are successful in reducing chronic nerve pain.
What to Expect After a Nerve Block
You may feel temporarily numb or sore after your nerve block, and you may notice some redness or irritation to the area. This is usually not permanent and should fade with time. If you have had a surgical block, you may be asked to rest for a certain time after your procedure. Depending on the complexity of the surgery, you may have to spend a few days recovering in the hospital.
Some pain may persist after your nerve block, but this doesn’t mean the procedure was not effective. Some nerve blocks may cause swelling, which compresses the nerve and requires time to subside. If you find the side effects of your nerve block are lasting longer than expected, be sure to contact your doctor.
American Pain Foundation. Treatment Options: A Guide for People Living With Pain. Accessed 6/9/09. http://www.painfoundation.org/Publications/TreatmentOptions2006.pdf
National Institute of Neurological Disorders and Stroke. Pain: Hope Through Research. Accessed 6/9/09. http://www.ninds.nih.gov/disorders/chronic_pain/detail_chronic_pain.htm
Nocom G, Ho KY and Perumal M. Interventional Management of Chronic Pain. Annals of the Academy of Medicine, Singapore. 2009 Feb;38(2):150-5.