What is a nerve block?
A nerve block, or neural blockade, is a method of producing anesthesia — a loss of feeling used to prevent or control pain. Nerve blocks can be surgical or nonsurgical.
Nonsurgical nerve blocks involve injection of a medication around a specific nerve or a bundle of nerves. The medication prevents the nerves’ impulses from reaching the central nervous system (CNS) and making you feel pain. Instead, that part of your body will feel numb, or you might feel a “pins and needles” sensation.
Surgical nerve blocks involve deliberately cutting or destroying specific nerves to prevent them from sending out impulses to the CNS.
A nerve block can last anywhere from 12 to 36 hours depending on the type used. Surgical nerve blocks may be permanent.
A nerve block may be used as the sole form of pain relief or combined with another type of anesthetic.
Nerve blocks are most commonly used to prevent or control pain. A nerve block is more effective than medications given through an intravenous (IV) line. Your doctor may want to use a nerve block to manage the following types of pain:
- pain from labor and childbirth
- pain before, during, and after a surgery, such as a joint or knee replacement
- cancer-related pain
- arthritis pain
- low back pain or sciatica
- chronic regional pain syndrome
- neck pain caused by herniated disks
- phantom pain after an amputation
- lingering pain from a shingles infection
- pain from spasms in the blood vessels
- excessive sweating (hyperhidrosis)
- Raynaud’s syndrome
Other uses for nerve blocks
A nerve block might also be used as a diagnostic tool to find out where your pain is originating from. By seeing how a nerve block affects your pain, your doctor may be able to determine the reason for this pain and how to treat it.
There are no special preparations needed for a nerve block. You can eat and drink normally beforehand. Don’t take any anti-inflammatory medicines, such as ibuprofen (Advil) or naproxen, within 24 hours of your nerve block procedure. If you take blood thinners such as aspirin (Bufferin), heparin, or warfarin (Coumadin), inform your doctor before scheduling a nerve block.
If you’re having a nerve block for a surgery, your doctor might have some specific instructions for you to follow prior to your surgery, especially if several types of anesthetic are going to be used. This might include not eating or drinking anything for 6 to 12 hours prior to your surgery. Be sure to confirm these instructions with your doctor ahead of your surgery day.
Make sure you have someone available to take you home after the procedure. People who’ve had a nerve block shouldn’t drive themselves home.
In general, the procedure for a nerve block involves these steps:
- The skin around the injection site is cleaned.
- A local anesthetic is used to numb the injection site area.
- Once numb, your doctor inserts a needle into the area with the help of an ultrasound, fluoroscope, CT scan, or simulator to aid in guiding the needle and distributing the medication to the right area.
- Once the proper placement of the needle is confirmed, the doctor will inject the anesthetic medication.
- You will be moved to a recovery area and monitored for adverse reactions.
- If the nerve block was done for diagnostic purposes, your doctor will ask you whether it has clearly reduced your pain.
The entire procedure will likely take less than 30 minutes.
Pain originating from different areas of the body require different nerve blocks. Examples include:
Upper extremity (brachial plexus) nerve blocks
- interscalene (shoulder, clavicle, or upper arm)
- supraclavicular (upper arm)
- infraclavicular (elbow and below)
Facial nerve blocks
- trigeminal (face)
- ophthalmic (eyelids and scalp)
- supraorbital (forehead)
- maxillary (upper jaw)
- sphenopalatine (nose and palate)
Neck and back nerve blocks
- cervical epidural (neck)
- thoracic epidural (upper back and ribs)
- lumbar epidural (lower back and buttocks)
Chest and abdominal nerve blocks
- paravertebral (chest and abdomen)
- intercostal (chest/rib)
- transversus abdominis plane (lower abdomen)
Lower extremity nerve blocks
- hypogastric plexus (pelvic region)
- lumbar plexus (front of the leg, including the thigh, knee, and the saphenous below the knee)
- femoral (the entire anterior thigh, most of the femur and knee joint, and part of the hip joint, but not the back of the knee — often used for a knee replacement surgery)
- sciatic nerve (back of the leg, lower leg, ankle, and foot), which includes popliteal nerve blocks (below the knee)
A nerve block can also be classified by how the injection is administered or by whether it’s nonsurgical or surgical:
Nonsurgical nerve blocks
- Epidural: Medication is injected outside the spinal cord to numb the abdomen and lower extremities. An epidural is probably the most commonly recognized type of nerve block and is often used during childbirth.
- Spinal anesthesia: The anesthetic medication is injected in the fluid surrounding the spinal cord.
- Peripheral: Medication is injected around a target nerve that is causing pain.
Surgical nerve blocks
- Sympathetic blockade: Blocks pain from the sympathetic nervous system in one specific area. This may be used to treat excessive sweating in specific parts of the body.
- Neurectomy: A damaged peripheral nerve is surgically destroyed; this is only used in rare cases of chronic pain, where no other treatments have been successful, such as chronic regional pain syndrome
- Rhizotomy: The root of the nerves that extend from the spine are surgically destroyed. This may be used for neuromuscular conditions such as spastic diplegia or spastic cerebral palsy.
A nerve block typically lasts between 8 and 36 hours depending on the type of nerve block. The feelings and movement in that part of the body will come back gradually.
In some cases, your doctor may use a nerve catheter to continuously provide numbing medication to the nerve over the course of two to three days following a surgery. A small tube is placed below the skin near the nerve. This is connected to an infusion pump, which delivers the anesthetic continuously for a specified period of time.
Most surgical nerve blocks can be considered permanent. But they are often reserved for rare cases of chronic pain when no other treatments have been successful, such as cancer pain or chronic regional pain syndrome.
In a permanent nerve block, the nerve itself is completely destroyed either by deliberating cutting the nerve, removing it, or damaging it with small electrical currents, alcohol, phenol, or cryogenic freezing.
However, not all permanent nerve destruction procedures actually end up being permanent. They may only end up lasting a few months because the nerve can regrow or repair itself. When the nerve grows back, the pain may return, but it’s also possible that it won’t.
Nerve blocks are very safe, but like any medical procedure, a nerve block carries some risks. In general, nerve blocks carry fewer side effects than most other types of pain medications.
Risks and side effects of a nerve block include:
- injection site tenderness
- blocking the wrong nerve
- Horner’s syndrome, which causes drooping eyelid and decreased pupil size when the nerve between the brain and the eye is affected (usually goes away on its own)
- damage to nerves (extremely rare and usually temporary)
- overdose (rare)
The area that has been blocked may remain numb or weak for up to 24 hours. During this time, you probably won’t be able to tell if something is painful. You’ll have to be careful not to place hot or very cold things on the area or to bump, injure, or cut off circulation to the affected area.
You should call your doctor if the numbness or weakness doesn’t go away after 24 hours.
There are many different options for pain relief. While your doctor will often strongly advise one option over another, in some cases you’ll have a choice between different types of anesthetics, including a nerve block. Speak to your doctor to learn more about the pros and cons of each pain management option. Your doctor and anesthesiologist will work together with you to determine if a nerve block will provide the best anesthetic conditions with the least side effects for your particular situation.
If a nerve block is being done as a diagnostic tool, your doctor will likely recommend treatment or additional tests based on how your pain responded to the block.