Regional Anesthesia: Nerve Blocks

  

Regional anesthesia is the final and most convenient way to treat an affected area of the body. Regional anesthesia affects a much bigger portion of the body than the previously discussed local anesthetics, like the -caine family, but not so broad as to affect the entire body, like previously discussed when talking about general anesthetics. In regional anesthesia, your anesthesiologist makes an injection near a cluster of nerves to numb the area of your body that requires surgery.

With regional anesthesia, the type of anesthetics permits that those undergoing surgery can be awake, if using different types of sedation. During minimal sedation, you will feel relaxed, and you may be awake. You can understand and answer questions and will be able to follow your physician’s instructions. When receiving moderate sedation, you will feel drowsy and may even sleep through much of the procedure, but will be easily awakened when spoken to. You may or may not remember being in the operating room. During deep sedation, you will sleep through the procedure with little or no memory of the procedure room. Your breathing can slow, and you might be sleeping until the medications wear off.

One specific type of regional anesthesia is known as nerve blocks. The main job of nerve blocks is to relieve pain. Nerve blocks serve as a form of regional anesthesia because they numb only a certain area and patients going through surgery do not necessarily have to be sedated, like with general anesthesia. Typically nerve blocks are fast-acting, effective injections into the area of study.

Risks of Nerve Blocks

However, nerve blocks are not without 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 (hypotension), accidental injection of the alcohol or phenol into an artery, puncture of the lung, damage to the kidneys, diarrhea, and weakness in the legs. 

Epidural Nerve Blocks

 

One specific type of nerve block is known as an epidural block. This form of a nerve block occurs when a corticosteroid, or a certain type of drug that closely resembles cortisol, is manually injected into the epidural space of the spinal column. Receptors on the cell surface of the neurons in the spinal cord take up the injection due to the nonpolarity of the corticosteroid, and the entire back area will be numb from the effects of the drug soon afterwards. This sort of drug is very quick acting and is very useful for surgeries.

Peripheral Nerve Blocks

Peripheral nerve blocks are another kind of regional anesthetic. It affects regions other than the back or torso, in fact, it deals with the extremities, including the arms, legs, and head. Peripheral nerve blocks are performed slightly differently, because first, those administering the medicine have to find the cluster of nerves needed to sedate a certain area of the body. However, peripheral nerve blocks are also easy to use and consist of a majority of the regional anesthesia administered in recent times.

This video elaborates on the importance of peripheral nerve blocks .

Examples of peripheral nerve blocks include sciatic nerve blocks, femoral nerve blocks, paravertabral blocks, and brachial plexus blocks, among others.

Sympathetic Nerve Block

The autonomic nervous system, or the sympathetic nervous system regulates the functions of our internal organs such as the heart, stomach and intestines. The SNS is part of the peripheral nervous system and it also controls some of the muscles within the body. We are often unaware of the SNS because it functions involuntary and reflexively.

A sympathetic nerve block is one that is performed to determine if there is damage to the sympathetic nerve chain. This is a network of nerves extending the length of the spine. These nerves control some of the involuntary functions of the body, such as opening and narrowing blood vessels.

By doing this, the sympathetic nervous system in that area is temporarily ‘switched’ off in hopes of reducing or eliminating pain. If pain is substantially improved after the block, then a diagnosis of sympathetically mediated pain is established. The therapeutic effects of the anesthetic can occur, at times, longer than would be normally expected. The goal is to reset the sympathetic tone to a normal state of regulation. If the initial block is successful, then additional blocks may be repeated if the pain continues to sequentially diminish.

Conclusion

Typically, the effects of a nerve block injection are temporary and offer little to no long-term relief. Each individual is different; however, nerve block injections are often delivered in a series and then discontinued, depending on the results they achieve. A patient may feel benefits after a round of injections, or none at all. Delivery of the medication to the correct spot can fail, thereby rendering the injection ineffective. If the nerve blocks don’t help alleviate your pain, however, your doctor will most likely recommend a different treatment approach.

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