Plexus anesthesia is a form of local anesthesia. It is used during surgical procedures or for postoperative pain therapy through a catheter. For this purpose, the anesthetic is injected directly in the area of the nerve plexus and leads to a pain blockade in the extremity supplied by the nerve plexus.
What is plexus anesthesia?
Plexus anesthesia is a form of anesthesia. By blocking the nerves, the sensation of pain in the corresponding extremity is removed. Plexus anesthesia is a form of anesthesia. By blocking the nerves, the sensation of pain in the corresponding extremity is removed. This is brought about with a local anesthetic, a so-called local anesthetic. This type of partial anesthesia is indicated for surgical procedures on the upper and lower extremities. The local anesthetic is injected into the vicinity of nerves, nerve plexuses or the spinal cord. The decisive factor for the corresponding nerves is the supply area of the nerve fibers that are to be temporarily anesthetized. To eliminate the sensation of an extremity for a longer period of time, a catheter can be placed. Local anesthetic is continuously added through this catheter, prolonging partial anesthesia for ongoing surgery or postoperatively for pain management. The patient remains awake during the partial anesthesia, but may be given an additional drug to calm him or her down or to put him or her to sleep. This causes what is known as sedation, which puts the patient into a twilight sleep. After the surgical procedure, the patient can be awakened at any time.
Function, effect and goals
During plexus anesthesia, the anesthesiologist injects an anesthetic into the local nerve plexus or trunks. This blocks sensation and therefore pain transmission. The muscles are paralyzed in the area to be operated. The location where the anesthetic is injected depends on the area of the body that is to be operated on. This procedure is often used for the upper extremities. However, it is also suitable for anesthesia of the lower extremity. For the upper extremity, the arm is bent 90 degrees at the shoulder joint and at the elbow joint to have a clear view of the axilla. The puncture site is accessed using a device called a nerve stimulator. It is located approximately above the axillary artery. The nerve stimulator is connected to the puncture cannula at the end. If the needle tip of the cannula comes close to the nerve to be anesthetized, it makes itself felt by muscle contractions in the forearm. Alternatively, the puncture needle can also be guided to the corresponding plexus with the aid of an ultrasound. When injecting with the help of a nerve stimulator, about 40ml of anesthetic is injected. Long and highly effective anesthetics such as ropivacaine are preferred. It takes about 20 – 30 minutes for the full effect to occur. To accelerate this, a short and fast-acting substance such as prilocaine or mepivacaine can be added. The most common plexus anesthesia is applied in the brachial plexus. If a pain block is placed in this area, surgical procedures can be performed in the clavicle, shoulder, upper arm, elbow joint, forearm, and hand. A distinction is made between axillary blockade (within the armpit), vertical infraclavicular blockade (below the clavicle) and interscalene blockade (in the area of the neck muscles). The anesthesiologist specialist decides which pain blockade is indicated and implemented, depending on the patient’s medical history and the planned procedure. If surgical procedures have to be performed on the lower extremity, the plexus anesthesia is placed on the lumbosacral plexus. Pain blockade thus enables interventions in the thigh, knee, tibia, and fibula, as well as the ankle and foot. A major advantage of plexus anesthesia is that, unlike general anesthesia, it can be kept relatively minimally invasive. However, due to the possibility of placing a catheter, this anesthetic procedure can also be performed over a longer period of time and used postoperatively for pain management.Furthermore, plexus anesthesia supports the healing process, as the anesthetic dilates the blood vessels and thus the surgical area is better supplied with blood and, if necessary, inflammatory mediators and pain mediators can be removed.
Risks, side effects, and hazards
Plexus anesthesia is generally a very safe form of anesthesia. The typical postoperative side effects ,as with general anesthesia, are absent with plexus anesthesia. There is no nausea or vomiting, and since there is no need for intubation, there is no coughing or hoarseness. The risks of plexus anesthesia are similar to those of local anesthesia. For example, allergic reactions to the anesthetic may occur. In the case of anesthesia over a longer period of time, symptoms of intoxication may occur in the form of dizziness, nervousness, seizures, cardiac arrhythmia or drop in blood pressure. When advancing to the nerve plexus, it may happen that a vein or artery is damaged, as these run in the middle of blood vessels. Postoperatively, side effects such as numbness, muscle tremors or tingling of the anesthetized extremity may occur. However, experience shows that these sensory disturbances subside after a few weeks. Bleeding (hematoma) may occur in the area of the puncture site and the surrounding soft tissues. Furthermore, general damage to the soft tissues or nerve irritation may occur, despite adequate performance and positioning. This damage or irritation can cause sensory disturbances such as insensations, numbness, pain and even paralysis. A drop in blood pressure and pulse may occur as a reaction to the anesthetic. If the anesthetic is inadvertently injected into blood vessels, seizures, cardiovascular problems, unconsciousness and even respiratory failure may occur. Plexus anesthesia is contraindicated if there is an infection in the area of injection or if there is a known allergy to anesthetics.
