1. Ankle Block Soli Deo Gloria Lecture 15
Developing Countries Regional Anesthesia Lecture Series
Daniel D. Moos CRNA, Ed.D. U.S.A.
Lecture 15

2. Disclaimer
Every effort was made to ensure that material and information contained in this presentation are correct and up-to-date. The author can not accept liability/responsibility from errors that may occur from the use of this information. It is up to each clinician to ensure that they provide safe anesthetic care to their patients.

3. Introduction to the Ankle Block
Common peripheral nerve block
Useful for procedures that do not require a tourniquet above the ankle
Indicated for orthopedic and podiatry procedures of the distal foot
Purely sensory block
Painful block
Conscious sedation….don’t over sedate!

4. The ankle block involves blockade of 5 peripheral nerves
Posterior tibial nerve
Sural nerve
Superficial peroneal nerve
Deep peroneal nerve
Saphenous nerve

5. Anatomy

6. 4 of the 5 nerves are terminal branches of the sciatic nerve
Deep peroneal nerve
Superficial peroneal nerve
Posterior tibial nerve
Sural nerve

8. The remaining nerve is the terminal branch of femoral nerve
Saphenous nerve

9. Deep Peroneal Nerve Anatomy
Continues as an extension of the common peroneal nerve and enters the ankle between the flexor hallucis longus tendons.

10. Deep Peroneal Nerve provides sensation to the medial half of the dorsal foot (1st & 2nd digits)

11. Deep Peroneal Nerve can be located at the level of the medial malleolus just lateral to the flexor hallucis longus
Lateral
Malleolus
Medial Malleolus
Extensor Digitorum Longus
Extensor Hallucis Longus
Location of deep peroneal nerve

12. Superficial Peroneal Nerve Anatomy
Extension of the common peroneal nerve and enters the ankle lateral to the extensor digitorum longus at the level of the lateral malleolus

13. Superficial Peroneal Nerve

14. Superficial Peroneal Nerve provides sensation to the dorsum of the foot as well as all five toes

15. Posterior Tibial Nerve Anatomy
Extension of the tibial nerve and enters the foot posterior to the medial malleolus, dividing into the lateral and medial plantar nerves.

16. Posterior Tibial Nerve Anatomy
Located behind the posterior tibial nerve at the level of the medial malleolus
Posterior Tibial Nerve
Medial Malleolus

17. Posterior Tibial Nerve provides sensation to the heel, medial and lateral sole of the foot

18. Sural Nerve Anatomy
Extension of the tibial nerve and enters the foot between the Achilles tendon and lateral malleolus

19. Sural Nerve Anatomy
Located between the Achilles tendon and lateral malleolus
Lateral Malleolus
Sural Nerve

20. Sural Nerve provides sensation to the lateral foot

21. Saphenous Nerve Anatomy
Terminal branch of the femoral nerve located anterior to the medial malleolus

22. Saphenous Nerve Anatomy
Provides sensation to the anteromedial foot

23. Equipment Betadine and alcohol wipes Sterile gloves 4x4 or 2x2’s
Sterile towels
cc syringes with local anesthetic
25 gauge needle 1.5 inch needle

24. Choice of Local Anesthetic
Depends on the length of time you wish block to last
Longer acting local anesthetics may take longer for onset
May wish to mix a local anesthetic that has faster onset with a longer acting local anesthetic
Sodium bicarbonate may help speed onset
NEVER USE EPINEPHRINE!

25. Local Anesthetic Choices

26. Considerations Be careful with volume- tourniquet effect
Caution in patients with peripheral vascular disease and diabetics
Care with patient with infection- risk of tracking infection to healthy tissue and local anesthetic not working due to acidotic tissue

27. Positioning the foot
Position the foot so you have access to all 5 nerves

28. Blockade of the Deep Peroneal Nerve, Superficial Peroneal Nerve, and Saphenous Nerve can be blocked in one needle stick.

29. Deep Peroneal Nerve Block
Draw a line between the two malleoli
Identify the extensor hallucis longus tendon and the extensor digitorum longus muscle
Palpate the anterior tibial artery

30. Deep Peroneal Nerve Block
Place a skin wheal of local anesthetic lateral to the artery
Advance the needle perpendicular, aspirating for blood and deposit 3-5 ml of local anesthetic deep to the extensor retinaculum
May choose to fan the injection in this area, avoiding the artery

31. Deep Peroneal Nerve Block

32. Blocking the Superficial Peroneal Nerve
Bring the needle back and direct it superficially in a lateral fashion towards the lateral malleolus depositing 3-5 ml of local anesthetic subcutaneously

33. Blocking the superficial peroneal nerve

34. Blocking the saphenous nerve
At the site of the deep peroneal nerve blockade bring your needle back and redirect in a medial direction towards the medial malleolus depositing 3-5 ml of local anesthetic

35. Blocking the posterior tibial nerve
Warn your patient to hold still in case a paresthesia is elicited. Movement at this time may result in trauma to the nerve.
Identify the posterior tibial artery at the level of the medial malleolus and advance the needle in a posterolateral manner slowly.
If a paresthesia is elicited withdraw the needle slightly and inject 3-5 ml. Make sure the patient does not have pain as this may imply an intraneural injection.
If no paresthesia is elicited than inject 7-10 ml as you withdraw the needle. A paresthesia is not essential to a successful block.

36. Blocking the posterior tibial nerve

37. Blocking the sural nerve
Identify the lateral malleolus and the Achilles tendon
Insert needle superficially lateral to the tendon and in the direction of the lateral malleolus.
Inject 5-10 ml of local anesthetic subcutaneously as you withdraw the needle

38. Blocking the sural nerve

39. Complications Discomfort to the patient
Injury to a “numb” foot after discharge
Nerve injury or paresthesia’s
Hematoma and vascular injury
Infection
Intravascular injection
Block failure

40. Conclusion Easy to administer Effective anesthesia
Often performed with much less local anesthetic than what textbooks advocate

41. Metatarsal Block
 A metatarsal block may supplement an ankle block if a nerve distribution has been missed.
Never use epinephrine containing solutions. This can result in ischemia of the digits.
Place a small skin wheal at the site of injection on the dorsum of the foot.
Advance the needle while injecting local anesthetic parallel to the metatarsal bone. Do not go through the surface of the sole of the foot!

42. Metatarsal Block
The individual nerves are located closer to the sole of the foot than the dorsum.
A total of 3-5 ml of local anesthetic solution may be deposited.
The same procedure should occur on the other side of the metatarsal of the location that anesthesia is desired.

43. Metatarsal Block
Metatarsals

44. References
Burkard J, Lee Olson R., Vacchiano CA. Regional Anesthesia. In Nurse Anesthesia 3rd edition. Nagelhout, JJ & Zaglaniczny KL ed. Pages
Morgan, G.E. & Mikhail, M. (2006). Peripheral nerve blocks. In G.E. Morgan et al Clinical Anesthesiology, 4th edition. New York: Lange Medical Books.
Wedel, D.J. & Horlocker, T.T. Nerve blocks. In Miller’s Anesthesia 6th edtion. Miller, RD ed. Pages Elsevier, Philadelphia, Penn
Wedel, D.J. & Horlocker, T.T. (2008). Peripheral nerve blocks. In D.E. Longnecker et al (eds) Anesthesiology. New York: McGraw-Hill Medical.