Local anesthesia is any technique to induce the absence ofsensation in a specific part of the body,[1] generally for the aim of inducinglocal analgesia, i.e. local insensitivity topain, although other local senses may be affected as well. It allows patients to undergo surgical anddental procedures with reduced pain and distress. In many situations, such ascesarean section, it is safer and therefore superior togeneral anesthesia.[2]
The following terms are often used interchangeably:
Local anesthesia, in a strict sense, isanesthesia of a small part of the body such as a tooth or an area of skin.
Regional anesthesia is aimed at anesthetizing a larger part of the body such as a leg or arm.
Conduction anesthesia encompasses a great variety of local and regional anesthetic techniques.
A local anesthetic is adrug that causes reversible local anesthesia and a loss ofnociception. When it is used on specific nerve pathways (nerve block), effects such asanalgesia (loss ofpain sensation) andparalysis (loss ofmuscle power) can be achieved. Clinical local anesthetics belong to one of two classes: aminoamide and aminoester local anesthetics. Synthetic local anesthetics are structurally related tococaine. They differ from cocaine mainly in that they have no abuse potential and do not act on thesympathoadrenergic system, i.e. they do not producehypertension or localvasoconstriction, with the exception ofRopivacaine andMepivacaine that do produce weak vasoconstriction. Unlike other forms of anesthesia, a local can be used for a minor procedure in a surgeon's office as it does not put one into a state of unconsciousness. However, the physician should have a sterile environment available before doing a procedure in their office. Local anesthetics work primarily by reversibly blocking voltage-gated sodium channels in neuronal membranes, which prevents the initiation and propagation of action potentials along sensory nerves. This blocks nociceptive signals from reaching the brain.
Local anesthetics vary in theirpharmacological properties and they are used in various techniques of local anesthesia such as:
Topical anesthesia (surface) - Surface application on mucous membranes or skin.
Infiltration anesthesia: Direct injection into tissue near the site of the procedure.
Peripheral nerve blocks: Injection near specific nerves or plexuses (e.g., brachial, femoral).
Neuraxial anesthesia: Includes spinal and epidural techniques, which anesthetize broader regions through nerve root blockade.
Adverse effects depend on thelocal anesthetic method and site of administration discussed in depth in thelocal anesthetic sub-article, but overall, adverse effects can be:
localized prolongedanesthesia orparesthesia due to infection,hematoma, excessive fluid pressure in a confined cavity, and severing of nerves & support tissue during injection.[3]
Regional anesthesia has a rich history dating back to the late 19th century, with key pioneers advancing its development.Karl Koller introducedcocaine as the first local anesthetic in 1884, revolutionizing pain management.[4]
Gaston Labat, often called the "father of regional anesthesia in America," founded the American Society of Regional Anesthesia in 1923 and authored the influential textbookRegional Anesthesia: Its Technic and Clinical Application. His work standardized techniques and promoted the field's growth.[6]
^Goerig, Michael; Bacon, Douglas; van Zundert, André (2012). "Carl Koller, cocaine, and local anesthesia: some less known and forgotten facts".Regional Anesthesia and Pain Medicine.37 (3):318–324.doi:10.1097/AAP.0b013e31825051f3.ISSN1532-8651.PMID22531385.
^Rasche D, Ruppolt M, Stippich C, Unterberg A, Tronnier VM (2006). "Motor cortex stimulation for long-term relief of chronic neuropathic pain: a 10 year experience".Pain.121 (1–2):43–52.doi:10.1016/j.pain.2005.12.006.PMID16480828.S2CID24552444.
