Posterior Ankle Nerve Block

1. Indications
   1. Anesthesia of the sole of the foot
2. Precautions
   1. Avoid injecting directly into nerves
   2. Avoid injection into posterior tibial artery
3. Preparation
   1. Needle: 27 gauge 1.5 inch
   2. Anesthetic: Lidocaine 1%: two 10 ml syringes
4. Technique
   1. Patient position
      1. Prone position
      2. Ankle slightly dorsiflexed
   2. Injection site 1: Sural nerve
      1. Lateral border of achilles tendon and
      2. Proximal to lateral malleolus tip by 1-2 cm
      3. Distribute anesthetic
         1. Redirect needle several times
   3. Injection site 2: Posterior tibial nerve
      1. Anteror and medial to achilles tendon border
      2. Proximal to medial malleolus tip by 1-2 cm
      3. Insert needle toward tibial artery
         1. Attempt aspiration confirming not in tibial artery
         2. Inject 5 cc near tibial nerve
         3. Inject additional 3-5 cc while withdrawing needle
   4. Warning: Distal Paresthesias with needle with injection
      1. Indicates needle is in nerve
      2. Do not inject here!
      3. Remove needle and reposition
5. References
   1. Pfenninger (1994) Procedures, Mosby, p. 1036-54
   2. Salam (2004) Am Fam Physician 69(4):896