EMed

Ulnar nerve block

Background

  • Will anaesthetise the ulnar side of the hand from wrist crease to the tips of the fingers on both palmer and dorsal sides
  • Ulnar nerve blocks can be done "blind" or under ultrasound guidance

Equipment:

  • Something to clean the skin
  • 1% lignocaine in one syringe, with a 25G needle for skin infiltration
  • 0.5% Bupivacaine in another syringe(22G anaesthetic needle for the nerve block)

LA toxicity

  • The toxic dose for Lignocaine is 3 mgs per kilo or 20 mls of 1% Lignocaine for an adult
  • In a child = 1 ml of 1% plain Lignocaine for each year of the child's age
  • Before any regional anaesthesia ensure you are familiar with the signs / management of LA Toxicty

Procedure

Ulnar Nerve Block
  • Palpate the tendon of flexor carpi ulnaris at its insertion on pisiform at the distal wrist crease
  • Introduce your needle deep to tendon on ulnar side and aim to inject on radial side deep to the flexor carpiulnaris
  • Aspirate first, then inject 3 to 4 ml of 1% lignocaine
  • Then inject a further 2 to 3 mls just distal dorsal ulna styloid to anaesthetize the proximal dorsal sensory branch

Complications

  • Intraneural injection - beware any resistance or pain on initial injection - do not inject into the nerve itself. Intraneural injection may cause permanent (ischaemic) nerve damage
  • Intravascular injection (LA toxicity or haematoma formation)
  • Infection (use no touch technique in all)

Content by Dr Íomhar O' Sullivan 26/12/2018. Last review Dr ÍOS 24/10/22.