Nerve block: digital block
- Each digit is innervated by 4 nerves
- 2 Dorsal (10 and 2 o'clock positions)
- 2 Ventral - palmar or plantar (4 and 8 o'clock positions)
- Need to anesthetize entire digit (finger or toe)
- Overlying skin infection
- Distortion of landmarks
- Local anesthetic
- 27-30ga needle
- 5-10 mL Syringe
- Iodine or chlorhexadine prep
|Agent||Without Epinephrine||With Epinephrine||Duration||Notes|
|Lidocaine||5 mg/kg (max 300mg)||7 mg/kg (max 500mg)||30-90 min||
|Mepivicaine||7 mg/kg||8 mg/kg|
|Bupivicaine||2.5 mg/kg (max 175mg)||3 mg/kg (max 225mg)||6-8 hr||
|Tetracaine||1 mg/kg||1.5 mg/kg||3hrs (10hrs with epi)|
|Procaine||7 mg/kg||10 mg/kg||30min (90min with epi)|
Epinephrine in Digital Block
- Previously, "conventional wisdom" argued that it is unsafe to use epinephrine in digital local anesthesia.
- However, many studies going back more than a decade have shown that using local anesthetic with epinephrine is safe for use in digits.
- A Cochrane Review concurs that no adverse effects have been reported, but notes that the level of evidence is poor and further high quality studies are required.
- Cleanse skin at proximal, dorsal aspect of the digit to be anesthetized, including web space
- Introduce the needle at the base of the digit near the MCP joint, lateral to the midline of the digit.
- Advance the needle around the bone towards the ventral side of the digit - stop if skin tenting is noted
- Inject ~1mL of anesthetic to block ventral digital nerve
- As needle is withdrawn, inject additional ~1mL of anesthetic to block dorsal digital nerve
- Repeat on opposite side of digit
Described for finger blocks - most effective in 2nd-5th digits
Contraindicated if flexor tendon involvement or infection (e.g. felon, tenosynovitis, etc)
- With hand supinated, locate flexor tendon of finger to be anesthetized
- Cleanse skin over the distal palmar crease and proximal digital crease
- Method 1
- Insert needle 90 degrees to the skin at the proximal digital crease
- Advance until needle hits bone, then withdraw 2-3mm
- Redirect needle 45 degrees to the skin with needle pointing distally (towards finger tip)
- Slowly inject anesthetic - initially no resistance, progressive resistance felt as tendon sheath fills (~1.5-3mL)
- Method 2
- Insert needle at 45 degrees to the skin just distal to the distal palmar crease
- Advance into flexor tendon sheath
- Slowly inject anesthesic - if resistance to injection felt, withdraw needle slightly
- Damage to surrounding structures
- Accidental intravascular injection of anesthetic
- Denkler K. A comprehensive review of epinephrine in the finger: to do or not to do. Plast Reconstr Surg. 2001 Jul;108(1):114-24.
- Krunic AL, Wang LC, Soltani K, Weitzul S, Taylor RS. Digital anesthesia with epinephrine: an old myth revisited. J Am Acad Dermatol. 2004 Nov;51(5):755-9.
- Chowdhry S, Seidenstricker L, Cooney DS, Hazani R, Wilhelmi BJ. Do not use epinephrine in digital blocks: myth or truth? Part II. A retrospective review of 1111 cases. Plast Reconstr Surg. 2010 Dec;126(6):2031-4
- Prabhakar H, Rath S, Kalaivani M, Bhanderi N. Adrenaline with lidocaine for digital nerve blocks. Cochrane Database Syst Rev. 2015 Mar 19;3
- Harness NG. Digital block anesthesia. J Hand Surg Am. 2009 Jan;34(1):142-5.
- Hill RG Jr, Patterson JW, Parker JC, et al. Comparison of transthecal digital block and traditional digital block for anesthesia of the finger. Ann Emerg Med. 1995 May;25(5):604-7.
- Hart RG, Fernandas FA, Kutz JE. Transthecal digital block: an underutilized technique in the ED. Am J Emerg Med. 2005 May;23(3):340-2.