Definition
The task of peripheral nerves is to transmit information such as pain information from the body to the brain, where it is switched and processed. Furthermore, the brain and spinal cord transmit their commands, for example to move muscles, via the same nerves to the corresponding target organ. In the case of nerve blockage, it is possible to anaesthetize individual nerves with the help of a drug, usually a local anaesthetic, such as “sciatica“, which runs across the buttocks to the foot, or the ulnar nerve, better known as the funny bone.
However, it is also possible to eliminate entire nerve plexuses, so-called plexus (singular plexus), which are located on the arms and legs and from which the individual nerves emerge. In addition, the nerve root can also be anaesthetised directly after leaving the spinal cord. The local anesthetic is applied to the nerve with a syringe or catheter.
The peripheral nerves can be switched off temporarily or permanently. Peripheral nerve blockage of the femoral nerve (nervus femoralis) is a form of regional anesthesia that enables targeted pain relief in the leg. At the same time, the leg can also be controlled to a limited extent, as feeling and strength are also temporarily reduced.
Materials and drugs used for peripheral nerve blockage have been specially developed to minimize the risk of damage to the nerve. For this reason, permanent damage caused by peripheral nerve blockage is extremely rare and the anesthetic effect can be largely centered on the area of the surgical procedure. After a single injection of local anesthetics, the treated surgical area is numbed for several hours. If a longer-term anaesthesia is desired, a catheter (fine plastic tube) can also be used to continuously administer the anaesthetic medication.
Implementation
To locate the nerve to be anaesthetized, weak electrical impulses are introduced into the tissue via an injection needle at the beginning of the anaesthesia. As soon as the impulses stimulate the nerve to be anaesthetised, characteristic involuntary muscle twitches occur. Once the correct position of the injection needle has been ensured in this way, the nerve is anaesthetised.
The leg is supplied by the two major nerves, the femoral and the sciatic nerve. The femoral nerve runs in the inguinal canal and is therefore anaesthetised just below the groin. For this purpose, approx. 15-20ml local anesthetics (e.g. Xylonest1%® or Naropin0.75%®) are injected.