Infiltration anesthesia is the injection of a local anesthetic intradermally (into the skin), subcutaneously (into the subcutaneous fat), or intramuscularly (into the muscles) to temporarily interrupt pain conduction. Along with surface anesthesia and regional anesthesia, infiltration anesthesia belongs to the higher-level field of local anesthesia. The method is used primarily for minor surgical procedures, such as wound care or dental surgery. However, infiltration anesthesia is increasingly being used for major surgical procedures as well. A special form of infiltration anesthesia is tumescent anesthesia, which is used for cosmetic procedures such as liposuction.
Indications (areas of application)
- Biopsy (tissue sampling) – e.g. histological (fine tissue) examination of a nevus (birthmark).
- Cosmetic surgery (tumescent anesthesia).
- Wound care – e.g., wound suture.
- Dental surgery
Contraindications
- Allergy to the local anesthetic
- Infection or inflammation at the puncture site.
- When epinephrine is added: use on the acras (auricle, nose, penis, fingertips).
Before infiltration anesthesia
No special precautions need to be taken before infiltration anesthesia is performed. However, allergy to the local anesthetic used should be ruled out in advance.
The procedure
First, the area to be anesthetized is disinfected. The first step is to place a skin paddle by injecting the local anesthetic. Then, from there, the region to be anesthetized is infiltrated in a fan shape. To minimize discomfort to the patient, the anesthetic effect of each injection should be waited for before each new puncture. If the affected region is very large, mild sedation of the patient may be helpful. The effect is usually very rapid, so that the procedure can be started promptly.
A number of local anesthetics can be used for infiltration anesthesia, and their use is adjusted individually. Some anesthetics include lidocaine, mepivacaine, and prilocaine. In addition to the local anesthetics, a vasopressor (drug that has a vasoconstrictor effect), usually epinephrine, is also injected, which improves the blockade and reduces the risk of systemic anesthetic bleeding. However, epinephrine should not be used when anesthetizing end-stream areas (acras), such as the fingers, because otherwise severe vasoconstriction (vasoconstriction) can result in necrosis (tissue death; in this case, due to lack of blood flow).
Possible complications
- Allergic reaction to the local anesthetic.
- Bleeding
- Vascular puncture
- Toxicity of local anesthetic with systemic effect.