Local anesthesia is any technique to induce the absence of

sensation Sensation (psychology) refers to the processing of the senses by the sensory system. Sensation or sensations may also refer to: In arts and entertainment In literature * Sensation (fiction), a fiction writing mode * Sensation novel, a Britis ...

in a specific part of the body, generally for the aim of inducing local analgesia, that is, local insensitivity to pain, although other local senses may be affected as well. It allows patients to undergo surgical and dental procedures with reduced pain and distress. In many situations, such as

cesarean section Caesarean section, also known as C-section or caesarean delivery, is the surgical procedure by which one or more babies are delivered through an incision in the mother's abdomen, often performed because vaginal delivery would put the baby or ...

, it is safer and therefore superior to

general anesthesia General anaesthesia (UK) or general anesthesia (US) is a medically induced loss of consciousness that renders the patient unarousable even with painful stimuli. This effect is achieved by administering either intravenous or inhalational general ...

. The following terms are often used interchangeably: * ''Local anesthesia'', in a strict sense, is anesthesia 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.

Medical

A local anesthetic is a drug that causes reversible local anesthesia and a loss of nociception. When it is used on specific nerve pathways (

nerve block Nerve block or regional nerve blockade is any deliberate interruption of signals traveling along a nerve, often for the purpose of pain relief. Local anesthetic nerve block (sometimes referred to as simply "nerve block") is a short-term block, ...

), effects such as

analgesia Pain management is an aspect of medicine and health care involving relief of pain (pain relief, analgesia, pain control) in various dimensions, from acute and simple to chronic and challenging. Most physicians and other health professional ...

(loss of pain sensation) and paralysis (loss of muscle power) can be achieved. Clinical local anesthetics belong to one of two classes: aminoamide and aminoester local anesthetics. Synthetic local anesthetics are structurally related to

cocaine Cocaine (from , from , ultimately from Quechua: ''kúka'') is a central nervous system (CNS) stimulant mainly used recreationally for its euphoric effects. It is primarily obtained from the leaves of two Coca species native to South Ameri ...

. They differ from cocaine mainly in that they have no abuse potential and do not act on th
sympathoadrenergic system
i.e. they do not produce hypertension or local

vasoconstriction Vasoconstriction is the narrowing of the blood vessels resulting from contraction of the muscular wall of the vessels, in particular the large arteries and small arterioles. The process is the opposite of vasodilation, the widening of blood vess ...

, with the exception of

Ropivacaine Ropivacaine (rINN) is a local anaesthetic drug belonging to the amino amide group. The name ropivacaine refers to both the racemate and the marketed ''S''-enantiomer. Ropivacaine hydrochloride is commonly marketed by AstraZeneca under the brand na ...

and Mepivacaine 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 you into a state of unconsciousness. However, the physician should have a sterile environment available before doing a procedure in their office. Local anesthetics vary in their

pharmacological Pharmacology is a branch of medicine, biology and pharmaceutical sciences concerned with drug or medication action, where a drug may be defined as any artificial, natural, or endogenous (from within the body) molecule which exerts a biochemica ...

properties and they are used in various techniques of local anesthesia such as: * Topical anesthesia (surface) - Similar to topical gel numbing before getting injected with Lidocaine. * Infiltration * Plexus block Adverse effects depend on the

local anesthetic A local anesthetic (LA) is a medication that causes absence of pain sensation. In the context of surgery, a local anesthetic creates an absence of pain in a specific location of the body without a loss of consciousness, as opposed to a general a ...

method and site of administration discussed in depth in the

sub-article, but overall, adverse effects can be: # localized prolonged anesthesia or paresthesia due to infection, hematoma, excessive fluid pressure in a confined cavity, and severing of nerves & support tissue during injection. # systemic reactions such as depressed CNS syndrome, allergic reaction,

vasovagal episode Reflex syncope is a brief loss of consciousness due to a neurologically induced drop in blood pressure and/or a decrease in heart rate. Before an affected person passes out, there may be sweating, a decreased ability to see, or ringing in ...

, and cyanosis due to

local anesthetic toxicity A local anesthetic (LA) is a medication that causes absence of pain sensation. In the context of surgery, a local anesthetic creates an absence of pain in a specific location of the body without a loss of consciousness, as opposed to a general an ...

. # lack of anesthetic effect due to infectious pus such as an abscess.

Non-medical local anesthetic techniques

Local

pain management Pain management is an aspect of medicine and health care involving relief of pain (pain relief, analgesia, pain control) in various dimensions, from acute and simple to chronic and challenging. Most physicians and other health professionals pr ...

that uses other techniques than analgesic medication include: *

Transcutaneous electrical nerve stimulation Transcutaneous electrical nerve stimulation (TENS or TNS) is the use of electric current produced by a device to stimulate the nerves for therapeutic purposes. TENS, by definition, covers the complete range of transcutaneously applied currents ...

, which has been found to be ineffective for

lower back pain Low back pain (LBP) or lumbago is a common disorder involving the muscles, nerves, and bones of the back, in between the lower edge of the ribs and the lower fold of the buttocks. Pain can vary from a dull constant ache to a sudden sharp feel ...

, however, it might help with diabetic neuropathy. *

Pulsed radiofrequency Pulsed radiofrequency is the technique whereby radio frequency (RF) oscillations are gated at a rate of pulses (cycles) per second (one cycle per second is known as a hertz (Hz)). Radio frequency energies occupy 1.0 x 104 Hz to 3.0&nb ...

neuromodulation Neuromodulation is the physiological process by which a given neuron uses one or more chemicals to regulate diverse populations of neurons. Neuromodulators typically bind to metabotropic, G-protein coupled receptors (GPCRs) to initiate a second ...

, direct introduction of medication and nerve

ablation Ablation ( la, ablatio – removal) is removal or destruction of something from an object by vaporization, chipping, erosive processes or by other means. Examples of ablative materials are described below, and include spacecraft material for a ...

may be used to target either the tissue structures and organ/systems responsible for persistent nociception or the nociceptors from the structures implicated as the source of chronic pain.

References

External links

New York School of Regional Anesthesia

Anesthesia Books

General information and tutorials in peripheral regional anesthesia

worldanaesthesia.org
Free online manual of regional anaesthesia- John Hyndman
Clinical Use of Peripheral Nerve Stimulators and The Neuromuscular Junction

ESRA - The European Society for Regional Anaesthesia Congress
{{Authority control Anesthesia

Medical

Non-medical local anesthetic techniques

See also

References

External links