Where should local anesthesia be administered for incision (I) and drainage (D) of a finger abscess?

Local Anesthesia for Incision and Drainage of Finger Abscess

For incision and drainage of a finger abscess, administer local infiltrative anesthesia by directly injecting lidocaine with epinephrine into the tissues surrounding the abscess, avoiding injection into the abscess cavity itself. 1

Recommended Anesthetic Technique

Choice of Anesthetic Agent

• Use 1% lidocaine with epinephrine (1:100,000 or 1:200,000) as the primary anesthetic for finger abscess drainage 1, 2
• The historical dogma against using epinephrine in digits has been definitively refuted by multiple systematic reviews and randomized controlled trials showing no cases of digital necrosis 1, 2, 3
• Epinephrine provides significant benefits including prolonged anesthesia duration (by approximately 200%), improved hemostasis, and reduced systemic toxicity by slowing anesthetic absorption 1, 2

Injection Technique

• Infiltrate the anesthetic directly into the tissues around the abscess, creating a field block by injecting circumferentially at the base and sides of the abscess 1, 4
• Avoid injecting directly into the abscess cavity, as the acidic environment reduces anesthetic efficacy and may spread infection 4
• Use the lowest effective dose, typically 3-7 mL for most finger abscesses, with maximum safe doses of 7 mg/kg lidocaine with epinephrine (approximately 35-50 mL of 1% solution for a 70 kg adult) 1, 5, 3
• Aspirate before each injection to avoid intravascular administration 1

Pain Reduction Strategies

• Buffer the lidocaine solution with sodium bicarbonate (8.4% sodium bicarbonate mixed with lidocaine in a 1:9 or 1:10 ratio) to significantly reduce injection pain 1, 6
• Inject slowly using a small-gauge needle (27-30 gauge) to minimize discomfort 6
• Warm the anesthetic solution to body temperature before injection 6

Alternative Anesthetic Approaches

Digital Nerve Block

• A digital nerve block at the base of the finger is an alternative technique, though it offers no pain advantage over local infiltration when topical anesthesia is used first 7
• For digital blocks, inject at the dorsolateral aspects of the finger base, targeting the digital nerves bilaterally 7
• This technique may be preferred for larger abscesses or when extensive manipulation is anticipated 7

When to Avoid Local Anesthesia

• Consider general anesthesia or procedural sedation for patients with extensive cellulitis, multiple loculations, or signs of systemic sepsis requiring more extensive debridement 1
• Immunocompromised patients or those with diabetes and severe infection may require operating room drainage under general anesthesia 1

Critical Safety Considerations

Epinephrine Safety in Digits

• The American Academy of Dermatology provides Level A evidence (strongest recommendation) supporting epinephrine use in digits 1, 2
• No cases of digital necrosis have been reported in extensive clinical studies, even in patients with circulatory disorders, diabetes, hypertension, or on anticoagulation 3
• Use the lowest effective epinephrine concentration (1:100,000 or 1:200,000) 1, 2

Dosing Precautions

• Maximum recommended dose is 7 mg/kg of lidocaine with epinephrine (approximately 500 mg for a 70 kg adult) 1
• For children, use 3.0-4.5 mg/kg of lidocaine with epinephrine 1
• Continuously monitor the patient for early signs of local anesthetic systemic toxicity (perioral numbness, metallic taste, tinnitus, confusion) 1

Common Pitfalls to Avoid

• Do not inject anesthetic directly into the abscess cavity, as the acidic pH prevents effective anesthesia and may disseminate bacteria 4
• Do not delay drainage in systemically ill patients to achieve perfect anesthesia; proceed with available anesthesia or sedation 1
• Do not use unbuffered lidocaine when buffering is available, as this causes unnecessary pain during injection 1, 6
• Do not withhold epinephrine from digital procedures based on outdated concerns about digital necrosis 1, 2, 3