Local anesthesia is any technique to induce the absence of
sensation in a specific part of the body,[1] generally for the aim of inducing local analgesia, i.e. 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, it is safer and therefore superior to
general anesthesia.[2]
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.
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), effects such as
analgesia (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. They differ from cocaine mainly in that they have no abuse potential and do not act on the
sympathoadrenergic system, i.e. they do not produce
hypertension or local
vasoconstriction, with the exception of
Ropivacaine 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 properties and they are used in various techniques of local anesthesia such as:
Adverse effects depend on the
local anesthetic method and site of administration discussed in depth in the
local anesthetic 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.[3]
^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.
^Boswell MV, Trescot AM, Datta S, Schultz DM, Hansen HC, Abdi S, Sehgal N, Shah RV, Singh V, Benyamin RM, Patel VB, Buenaventura RM, Colson JD, Cordner HJ, Epter RS, Jasper JF, Dunbar EE, Atluri SL, Bowman RC, Deer TR, Swicegood JR, Staats PS, Smith HS, Burton AW, Kloth DS, Giordano J, Manchikanti L (2007).
"Interventional techniques: evidence-based practice guidelines in the management of chronic spinal pain"(PDF). Pain Physician. 10 (1): 7–111.
PMID17256025. Archived from
the original(PDF) on August 28, 2008.