Femoral nerve block

The nerve-femoral nerve block ( femoral nerve , 3-in-1 block , femoral nerve , inguinal paravascular art ) is a peripheral regional anesthesia procedure , the surgical procedures on the leg (the lower extremity enables). By injecting local anesthetics in the area of ​​the groin ( inguinal ), nerves of the lumbar plexus (mainly the femoral nerve , to a lesser extent the lateral femoral cutaneous nerve and the obturator nerve ) are reversibly blocked. The femoral nerve blockade is a relatively simple procedure that has few side effects. In addition to a single injection, the insertion of a pain catheter ( femoral catheter ) for continuous pain therapy is also often used .

development

The process was developed by Winnie in 1973 . This was believed to that the local anesthetic at the Faszienauskleidung the neurovascular sheath along the trunk out (after proximal spreads), where next to the femoral nerve , other branches of the lumbar plexus block ( lateral femoral cutaneous nerve , obturator nerve ), which is why he called the procedure a 3-in-1 block (three nerves, one injection). From today's point of view, however, this is hardly the case.

In 1980 Rosenblatt first described the technique of inserting a pain catheter close to the nerve, which enables continuous pain therapy through continuous or repeated injection.

application areas

The application can be combined with general anesthesia ( combination anesthesia ), but can also be carried out without such. Then, as a rule, a proximal sciatic nerve block is also performed. With this combination, all surgical interventions on the leg and foot are possible. Indications for the sole implementation of a femoral nerve block are operations in the supply area of ​​the femoral nerve ( muscle biopsies , skin grafts , vein operations), pain therapy during (for positioning , e.g. for femoral neck fractures ) and after an operation, as well as for wound care, early mobilization and physiotherapy . In knee replacement operations, the use of femoral nerve blocks has shown less pain, a shorter hospital stay and better mobilization success.

Contraindications (contraindications) are infections or tumors in the puncture area as well as rejection or lack of cooperation by the patient. Disorders of blood coagulation or taking anticoagulant drugs, nerve damage and a femoral vascular bypass represent relative contraindications.

execution

Ultrasound-controlled femoral nerve block (with catheter insert) on the right leg as part of a knee prosthesis operation.

The patient is positioned on his back with the leg on the relevant side slightly spread apart and rotated outward. The identification of the nerve in the groin region can be carried out in various ways. Often the search is carried out with the help of a nerve stimulator that is connected to the end of the puncture cannula. The puncture is done at the side ( laterally ) of the palpable artery ( arteria femoralis ). The position of the needle tip near the femoral nerve is indicated by muscle twitching in the quadriceps femoris muscle . This leads to movements of the kneecap ("dancing the patella"). Also, ultrasound-guided puncture is possible. It is associated with a more targeted injection and a shorter attack duration (around 15 minutes). If the position is correct, 20–30 ml of local anesthetic ( prilocaine , mepivacaine , ropivacaine ) are injected. If necessary, a pain catheter is placed.

Side effects

The complications correspond to the general side effects of peripheral regional anesthesia. Nerve damage can be caused by direct cannula injury or by toxic effects of local anesthetics that are accidentally injected into the nerves ( intraneurally ). This damage can be avoided by using blunt cannulas and avoiding injections in case of paresthesia during the procedure. The puncture of the leg artery can result in a bruise ( hematoma ). Accidental injection into blood vessels (intravascularly) can have effects on the cardiovascular system ( bradycardia , hypotension , cardiac arrest at high doses) or the central nervous system ( seizures , impaired consciousness ).

Overall, side effects of the femoral nerve block are rare. Compared to epidural anesthesia , which is an alternative regional anesthetic method for the leg, the analgesic effectiveness is comparable, but the side effect profile is more favorable. In addition, possible complications of epidural anesthesia close to the spinal cord ( epidural bleeding or infection) are avoided .

literature

• Danilo Jankovic: Regional blockades and infiltration therapy. 3. Edition. ABW Wissenschaftsverlag, Berlin 2003, ISBN 3-936072-16-7 .
• Gisela Meier, Johannes Büttner: Compendium of peripheral blockades. 6th edition. Arcis-Verlag, 2008, ISBN 978-3-89075-177-1 .
• Rolf Rossaint, Christian Werner, Bernhard Zwißler (ed.): The anesthesiology. General and special anesthesiology, pain therapy and intensive care medicine. 2nd Edition. Springer, Berlin 2008, ISBN 978-3-540-76301-7 .

Individual evidence

1. ^ AP Winnie, S. Ramamurthy, Z. Durrani: The inguinal paravascular technic of lumbar plexus anesthesia: the "3-in-1 block". In: Anesth Analg. Volume 52, No. 6, Nov-Dec 1973, pp. 989-996. PMID 4796576
2. ↑ RM Rosenblatt: Continuous femoral anesthesia for lower extremity surgery. In: Anesth Analg. Vol. 59, No. 8, Aug 1980, pp. 631-632. PMID 7190803
3. ^ R. Rossaint, C. Werner, B. Zwißler (eds.): Die Anästhesiologie. General and special anesthesiology, pain therapy and intensive care medicine. 2008, p. 692f.
4. ↑ SJ Fowler, J. Symons, S. Sabato, PS Myles: Epidural analgesia compared with peripheral nerve blockade after major knee surgery: a systematic review and meta-analysis of randomized trials. In: Br J Anaesth. Volume 100, No. 2, Feb 2008, pp. 154-164. Review. PMID 18211990

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