Nerve blocks for pain are injections that target a nerve or group of nerves with an anesthetic agent to reduce or eliminate pain signals being sent to the brain. The substance injected around the nerve depends on the severity and type of pain, and the injection site differs from case to case. Most nerve blocks are applied to the back, buttocks, arms, legs, neck, and face.
These injections usually serve as part of a larger pain management plan or a diagnostic plan. Nerve blocks can help doctors rule out certain areas of the body when identifying the source of a patient’s pain and help narrow down potential causes. Nerve blocks can reduce or eliminate pain for a few hours or days or provide longer-lasting relief, depending on the injection site and the injected medication.
Where Are Nerve Blocks For Pain Targeted?
The most likely neurological culprit determines the injection site. Most nerve blocks for pain are either epidural (injected into the outer sheath of the spine), spinal (injected into the fluid surrounding the spinal cord itself), or peripheral (targeting a specific nerve outside of the spine). The most varied targets for a nerve block are the peripheral nerves.
For example, a debilitating pain shooting down one buttock and leg, followed by weakness and muscle cramps, is characteristic of sciatica. Sciatica is often caused by nerve impingement near the spine, also known as lumbar radiculopathy. This could be caused by swelling, growths, or a herniated disc. In this case, a nerve block may be applied to the area around the sciatic nerve root to eliminate the pain signals flowing to the brain.
Another popular target for nerve blocks is the trigeminal nerve. This vital nerve, also known as the fifth cranial nerve, is a common troublemaker in patients with extreme chronic pain in and around the face.
Sympathetic nerve blocks are also used to address or treat problems with a patient’s sympathetic nervous system. These can include irregular heartbeat, hyperhidrosis (excessive sweating), complex regional pain syndrome, Raynaud’s syndrome, and pain caused by blood vessel spasms.
Your sympathetic nervous system is autonomous and subconsciously controls many functions, from swallowing to your physical reflexes. Certain disorders within this system can cause widespread and debilitating pain.
Nerve blocks target the ganglions or nerve clusters that are most relevant to your specific symptoms or disorder. Pain or symptoms mainly in the upper body may require a nerve block of a ganglion near the neck, for example.
Nerve blocks can also be used surgically as an anesthetic solution. For example, procedures on the leg or arm may involve a simple regional nerve block, after which the patient can remain awake while the surgery continues.
Because the nerves responsible for communicating with the brain will be temporarily put out of commission by the chemicals injected into the nerve, the patient won’t feel what’s going on behind the surgical curtain.
Doctors may also use a steroid injection to treat the pain. This is because corticosteroids reduce swelling, one common cause for nerve pain caused by impingement or compression.
What Is Injected During a Nerve Block?
The chemical or medication injected during a nerve block depends on the purpose of the block.
Short-term blocks meant to relieve pain or block out sensation during surgery utilize regional anesthetics, which tend to be an opiate solution (using a strong opiate such as fentanyl or morphine in small, diluted, and controlled doses).
When injected, the solution is targeted around the nerve, so each nerve cell binds with the solution, and no longer sends pain signals. The needle doesn’t physically touch the nerve itself.
When the pain needs to be managed or shut off for a more extended period due to a malfunctioning or damaged nerve, the nerve block may be used to destroy the nerve temporarily.
This will shut out the pain for much longer and hopefully cause the nerve to regenerate per its “original” specifications. This is called a neurolytic block and typically uses alcohol or a heating/cooling agent. The duration of a block of this kind is a few months.
Pain pumps are also a type of nerve block. In this case, a continuous stream of anesthetics (usually morphine) is pumped into the area surrounding the nerve at a slow, steady rate by a pump installed under the skin or kept close to the patient. The dose is carefully controlled to minimize side effects and primarily target the regional pain.
How Are Nerve Blocks Performed?
Most of the time, nerve blocks are performed by anesthesiologists or pain specialists, utilizing a special needle first to highlight the path towards the target nerve or cluster on a computer screen.
The computer is attached to a machine that uses x-rays to produce images of the body. The needle is used to inject a particular solution into the area that improves the quality of the picture.
Another needle is used to carefully find the best path towards the targeted area and then release the anesthetic or neurolytic agent around the nerve. Once the chemical or medication begins to envelop the nerve cells, the pain relief will set in.
As with most injections, the fear of the injection is much greater than the pain of the injection. The procedure only takes a few minutes.
When Are Nerve Blocks Used?
Nerve blocks are generally used whenever:
- The pain is chronic, cannot be addressed through surgical methods, and isn’t responding well to other types of treatment.
- The patient’s pain is targeted around a specific nerve or cluster and is debilitating.
- The origin of the patient’s pain isn’t clear, and a short-term nerve block may help identify the cause.
- There’s a need for a regional anesthetic before surgery.
Pain management tools differ significantly in purpose and application, with some serving as short-term relief with a wide range of effectiveness. In contrast, others are more specialized but may provide stronger targeted relief. Some tools and methods have more significant or different drawbacks, while others might be more conservative, safer, and less effective.
Understanding the risks of each tool and their respective relevance to a patient’s condition is a crucial part of a pain specialist’s job. Nerve blocks can be a powerful tool in a pain specialists’ arsenal, and when applied, can significantly help as both a diagnostics and treatment tool.