II. Indications
- Regional Anesthesia of the common peroneal nerve and tibial nerve
- Nerve Block covers everything below the knee except the saphenous nerve (medial calf to heal)
III. Contraindications
IV. Precautions
- Avoid injecting directly into nerves
- See Regional Anesthesia for complications
V. Preparation
- Needle: 22 to 25 gauge, 3.5 inch long spinal needle
- Skin preparation (e.g. Hibiclens or Betadine)
-
Anesthetic
- See Regional Anesthesia for Anesthetic options
- Local Anesthetic 2-5 ml (Ultrasound) or 5-10 ml (landmark)
VI. Technique: Ultrasound Guided
- Images
- Position
- Prone position
-
Ultrasound probe
- Linear probe transverse at posterior thigh, at least 5 cm above femoral condyles
- Injection site will lie between the biceps femoris and semiteninosus muscles and tendons
- Visualize the sciatic nerve bifurcation
- Landmarks
- Popliteal Artery and Vein are medial to the nerve
- Sciatic nerve bifurcates into peroneal nerve and tibial nerve at 5-12 cm above popliteal space
- Inject at or above the bifurcation into the peroneural sheath
- Injection
- Prepare needle site (e.g. hibiclens, drape)
- Insert needle inline with Ultrasound pobe from posterior or lateral approach
- Visualize needle enter perineural sheath near the nerve trunks (but not within nerves)
- Inject small amounts of Anesthetic at a time watching the fluid hydro-dissect tissue
- Inject up to 10-30 ml for block
- Do not exceed local Anesthetic limits to prevent LAST Reaction
- Post-procedure
- Reassess neurovascular exam
- Await Anesthetic effect within 10-30 minutes (see below)
VII. Pharmacokinetics
- See Ropivacaine
-
Lidocaine with 2% Epinephrine
- Onset: 10-20 minutes
- Duration: 2-5 hours
-
Bupivacaine (0.5%)
- Onset 15-30 minutes
- Duration: 6 to 30 hours
VIII. Resources
IX. References
- Warrington (2020) Crit Dec Emerg Med 34(3):12-3
- Yurgil (2020) Am Fam Physician 101(11):654-64 [PubMed]
