Nerve blocks may be used for several purposes:

• To determine the source of pain
• To treat painful conditions
• To predict how pain responds to long-term treatments
• For short-term pain relief after some surgeries and other procedures
• For anesthesia during some smaller procedures, such as finger surgery

Nerve blocks are used to treat chronic pain when drugs or other treatments do not control pain or cause bad side effects. A test block is usually performed with local anesthetic. If you achieve good pain relief from the local anesthetic, your doctor may inject a nerve block, such as alcohol or phenol.

What to expect after treatment
Nerve blocks numb the nerves touched by the drugs. This relieves pain by interrupting the pain signal sent by the nerves to your brain. Depending on the type of nerve block, your pain may be numbed for a short time or a long time.

Nerve blocks for chronic pain may work for 6 - 12 months. They may have to be repeated.

Why it is performed
Nerve blocks are used to diagnose the causes of pain. Nerve blocks are used to treat chronic pain when drugs or other treatments cause bad side effects or do not control pain.

Risks
Nerve blocks can cause serious complications, including paralysis and damage to the arteries that supply blood to the spinal cord. Other possible side effects include severely low blood pressure, accidental injection of the alcohol or phenol into the artery, puncture of the lung, damage to the kidneys, diarrhea and weakness in the legs.

Nerve blocks are not recommended if you have a disease that affects blood clotting, are taking blood-thinning drugs, have a bowel obstruction or have any type of uncontrolled infection.