What type of lidocaine (local anesthetic) is recommended for distal phalanx laceration repair?

Optimal Lidocaine Selection for Distal Phalanx Laceration Repair

For distal phalanx laceration repair, LET (lidocaine 4%, epinephrine 0.1%, and tetracaine 0.5%) topical gel is the preferred first-line anesthetic, followed by buffered 1% lidocaine with epinephrine for infiltration if needed. 1

First-Line Approach: Topical LET

• Apply LET gel directly to the open wound and cover with occlusive dressing or place cotton ball soaked with LET solution into wound
• Allow 10-20 minutes for full effect (until wound edges appear blanched)
• Dosing: 3 mL for patients >17 kg; 0.175 mL/kg in children <17 kg (based on maximum lidocaine dose of 5 mg/kg) 1
• Provides excellent wound anesthesia without the pain of injection

Second-Line Approach: Buffered Lidocaine Infiltration

If additional anesthesia is needed after LET application:

• Use 1% lidocaine with epinephrine buffered with sodium bicarbonate (1:9 or 1:10 ratio)
• Buffering decreases injection pain by 20-40% compared to plain lidocaine 1
• Technique for nearly painless injection:
  • Buffer with bicarbonate
  • Warm the lidocaine before injection
  • Use smallest gauge needle possible
  • Inject slowly 1

Considerations for Special Populations

• Children: Lower doses required (3.0-4.5 mg/kg lidocaine with epinephrine; 1.5-2.0 mg/kg without epinephrine) 1
• Patients with true lidocaine allergy: Use ester-type local anesthetics (procaine, tetracaine) as first alternative, or consider 1% diphenhydramine or bacteriostatic saline (0.9% benzyl alcohol in normal saline) for small excisions 1, 2

Duration Considerations

• For procedures requiring longer post-procedure analgesia, consider bupivacaine 0.25% which provides significantly longer pain relief (up to 5 hours) compared to lidocaine (wears off within 2 hours) 3

Pitfalls and Caveats

1. Avoid excessive dosing: Maximum safe doses for adults are 7 mg/kg lidocaine with epinephrine and 4.5 mg/kg without epinephrine 1
2. Monitor for toxicity: Watch for early signs of local anesthetic systemic toxicity (LAST) including circumoral numbness, facial tingling, slurred speech, and metallic taste 1
3. Allergy misconceptions: True lidocaine allergy is rare (only 1% of all adverse reactions); many reported "allergies" are actually vasovagal reactions or anxiety responses 2
4. Multiple LET applications: Research shows no benefit of three applications of LET compared to a single 30-minute application 4

LET provides excellent anesthesia for most distal phalanx lacerations, with buffered lidocaine infiltration as an effective supplement when needed. This approach minimizes pain during both anesthetic administration and repair while ensuring adequate anesthesia for the procedure.