A nerve block “turns off” the transmission of pain in the peripheral nervous system – the nerves on which it was performed. It is worth finding out how this anesthesia works, when can it be performed, and what the procedure looks like.
Among the many treatments for pain, peripheral nerve blocks deserve special mention. The nerve block is the administration of local anesthetics to the area of nerves, trunks, and nerve plexuses. This leads to a periodic “shutdown” of a given nerve in terms of pain transmission, the sensation of temperature, touch, and other stimuli.
The basis of the blockade is simple: if a structure is the source of the pain, blocking the nerve that conducts the pain will relieve it. The blockade is safe for local and regional anesthesia, but its performance requires the presence of an experienced anesthesiologist. Local anesthesia may be applied to various peripheral nerves. Frequently performed procedures include blockages of the sciatic, occipital, trigeminal, and femoral nerves. It prevents the recurrence of headaches, including migraines and neuralgia, and helps to discontinue the overuse of pain medications. The blockade does not worsen concentration and does not “fog” the mind, it does not burden the stomach, liver, or kidneys. It often allows avoiding unnecessary treatments and surgeries.
What is nerve blockage?
The nerve block injection is one type of local anesthetic and is performed with similar pharmacological agents as for dental infiltration anesthesia or for suturing. Blocks are reserved for a fairly narrow group of treatments, most often small operations in the field of limbs (e.g. wrist, foot), neck, or in dentistry.
The peripheral blockade is safe anesthesia but requires technical skills, experience, and knowledge of anatomy from the anesthesiologist. Relief of pain by a blockade lasts from several to several dozen hours, which is why this type of anesthesia is usually used before and during the procedure or after it. In certain cases, the so-called continuous blocks, allowing for long-term administration of anesthetic through a special catheter located in the vicinity of the nerve. This method is particularly useful in the treatment of postoperative and chronic pain.
The nerve block benefits are:
- The patient may remain conscious during surgery.
- The patient will not feel pain after the procedure for several to several dozen hours.
- There is little effect on the respiratory and circulatory systems; blockages are safer than general anesthesia.
- Lower probability of poor anesthetic tolerance, nausea, and vomiting.
- Compared to general anesthesia, there is a lower risk of thromboembolic complications.
- The blockade is used to numb a specific nerve responsible for conducting impulses in a given part of the body, the remaining nerves are still functioning properly.
- Possibility to use a permanent block.
- In addition to relieving pain, the blockade also inhibits inflammation, vascular spasms, and slightly relaxes the muscles around the injection site.
Epidural anesthesia, commonly called “spinal” anesthesia, is sometimes considered a special type of block, in which the pain transmission is inhibited at the level of nerve entry into the spinal canal.
What nerve blocks exist and when are they used?
Such anesthesias are used in many different situations, for example:
- minor surgery, usually to the extremities;
- persistent pain in the nerve or plexus, the cause of which cannot be cured, so-called chronic pain;
- as an addition to general anesthesia, if the surgery is extensive and painful;
- after surgery, if the pain persists after surgery, it applies to a specific anatomical location, and drugs administered orally are not fully effective or are contraindicated.
We use therapeutic, diagnostic, and prognostic blockades.
Diagnostic blocks are designed to establish the site of pain origin and the pathways of transmission.
The purpose of prognostic blocks is to establish the indications and effectiveness of planned other treatments that make damaged nerves (neurolysis, thermolysin, surgery) or a series of therapeutic blocks. Performing a prognostic block allows the patient to experience sensations after the procedure, and the doctor can assess the results of the planned procedure.
The purpose of using therapeutic blockades is to: reduce the inflammatory reaction, and facilitate physical therapy.
Blockage of the sciatic nerve
The largest nerve in the human body is the sciatic nerve. It innervates the muscle group of the thigh flexors, as well as the shin and foot. The sciatic nerve block is used especially in shin procedures, diabetic foot surgery, after major knee surgery, and in acute pain in the lower limb. This is not a spine blockage.
Blockage of the occipital nerve
The greater occipital nerve carries touch, pain, and temperature sensations to the scalp area. Its irritation often results in headaches, especially migraines, and chronic pains from the cervical spine. We can use this nerve block to:
- relieve pain in refractory migraines;
- reduce swelling and inflammation at the back of the head;
- stand against headaches during pregnancy;
- facilitate the discontinuation of reliever pain medications in patients who experience medication overuse headaches.
The trigeminal nerve belongs to the cranial nerves and is responsible for sensing in the area of the frontal, maxillary, and mandibular areas of the face, it is responsible for the innervation of the teeth, oral cavity, paranasal sinuses, conjunctiva, and cornea of the eye and is responsible for many other functions. Its damage or irritation causes severe pain called neuralgia, or facial pain. The trigeminal blockade is used when other treatments have failed. To obtain long-lasting effects, the treatment must be repeated.
Femoral nerve block
The femoral nerve is the largest in the lumbar plexus. It innervates the anteromedial area of the thigh, supplies the quadriceps muscle, the skin of the anteromedial area of the thigh, the hip joint, and the knee. The femoral nerve block is most often used in procedures performed on the front of the thigh and patella, as well as in knee surgery, skin grafts from the anterior thigh area, and in other justified cases of chronic pain.
There are many methods of anesthesia, they allow you to turn off the feeling of pain in a specific location or throughout the body. The choice of the type of anesthesia depends on the health condition, the possibility of complications, and the purpose of its use (ad hoc or for surgery). A very important aspect of local anesthesia is its safety – side effects practically do not occur, and if they do occur, they are harmless. What is equally important, for such analgesia you do not need any preparation, and you do not need to be on an empty stomach (unless the procedure itself requires it).