What is the recommended method for digital nerve block in finger burns?

Digital Nerve Block for Finger Burns

Digital nerve blocks are recommended as the preferred method for anesthesia in finger burns due to their ability to provide effective pain control with minimal tissue distortion and prolonged analgesia.

Recommended Technique for Digital Nerve Block in Finger Burns

Traditional Dorsal Approach

1. Preparation:

   • Use 1% lidocaine without epinephrine (epinephrine is contraindicated in digits) 1
   • Maximum dose: 4-5 mg/kg without exceeding 300 mg total
   • Consider buffering with sodium bicarbonate (9:1 ratio) to reduce injection pain

2. Technique:

   • Identify the two digital nerves running along the lateral and medial aspects of the finger
   • Insert a 25-27G needle at the dorsal web space at the base of the finger
   • Advance the needle to the volar aspect without penetrating too deeply
   • Inject 1-2 mL of anesthetic on each side (total 2-4 mL per digit)
   • Wait 5-10 minutes for complete anesthesia

Alternative: Volar Subcutaneous Approach

• Single injection at the volar aspect of the finger base
• Requires less total volume (2-3 mL)
• May cause less pain during injection 2, 3

Evidence-Based Considerations

Advantages of Digital Nerve Blocks for Burns

• Provides complete anesthesia of the entire digit
• Avoids tissue distortion that occurs with local infiltration 4
• Reduces total anesthetic volume needed
• Prolongs anesthesia duration compared to local infiltration
• Decreases postoperative discomfort 4

Duration of Action

• Lidocaine: 1-2 hours of pain relief
• Bupivacaine: Approximately 15 hours of pain relief (though numbness persists longer) 5
• Adding epinephrine to bupivacaine only extends pain relief by 1.5 hours and is generally contraindicated in digits 5

Efficacy Comparison

• No significant differences in time to anesthesia (average 4.5 minutes) between different digital block techniques 2
• Single-injection volar approaches may cause less pain during injection but dorsal approaches may provide better coverage of the proximal dorsal surface 2

Special Considerations for Burns

Multimodal Pain Management

• Digital nerve blocks should be part of a multimodal analgesic approach for burn patients 4
• Combine with systemic analgesics (acetaminophen, NSAIDs) for optimal pain control 4
• Consider ketamine for severe burn-induced pain that is difficult to control 4

Burn-Specific Precautions

• Ensure proper wound cooling before performing the block (if TBSA < 20% in adults or < 10% in children) 4
• Use sterile technique to avoid introducing infection
• Avoid performing blocks through infected or severely burned tissue
• Monitor distal circulation after the block, especially with circumferential burns

Common Pitfalls and Caveats

1. Avoid epinephrine-containing solutions in digits due to risk of ischemia and necrosis
2. Do not exceed maximum recommended doses of local anesthetics
3. Beware of compartment syndrome in circumferential burns - assess distal circulation every 15-30 minutes 6
4. Pain perception returns before normal sensation - patients should be informed that pain will return before normal sensation (especially with bupivacaine) 5
5. Consider early referral to burn center for burns involving hands, especially if circumferential 6

Digital nerve blocks represent an effective component of pain management for finger burns, providing excellent anesthesia while avoiding tissue distortion and allowing for proper wound assessment and care.