Soli Deo Gloria ANKLE BLOCK Developing Countries Regional Anesthesia Lecture Series Lecture 15 Daniel D. Moos CRNA, Ed.D. U.S.A. [email protected] 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. 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! The ankle block involves blockade of 5 peripheral nerves Posterior tibial nerve Sural nerve Superficial peroneal nerve Deep peroneal nerve Saphenous nerve Anatomy 4 of the 5 nerves are terminal branches of the sciatic nerve Deep peroneal nerve Superficial peroneal nerve Posterior tibial nerve Sural nerve The remaining nerve is the terminal branch of femoral nerve Saphenous nerve Deep Peroneal Nerve Anatomy Continues as an extension of the common peroneal nerve and enters the ankle between the flexor hallucis longus tendons. Deep Peroneal Nerve provides sensation to the medial half of the dorsal foot (1st & 2nd digits) Deep Peroneal Nerve can be located at the level of the medial malleolus just lateral to the flexor hallucis longus Medial Malleolus Extensor Hallucis Longus Location of deep peroneal nerve Lateral Malleolus Extensor Digitorum Longus 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 Superficial Peroneal Nerve Superficial Peroneal Nerve provides sensation to the dorsum of the foot as well as all five toes 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. Posterior Tibial Nerve Anatomy Located behind the posterior tibial nerve at the level of the medial malleolus Posterior Tibial Nerve Medial Malleolus Posterior Tibial Nerve provides sensation to the heel, medial and lateral sole of the foot Sural Nerve Anatomy Extension of the tibial nerve and enters the foot between the Achilles tendon and lateral malleolus Sural Nerve Anatomy Located between the Achilles tendon and lateral malleolus Lateral Malleolus Sural Nerve Sural Nerve provides sensation to the lateral foot Saphenous Nerve Anatomy Terminal branch of the femoral nerve located anterior to the medial malleolus Saphenous Nerve Anatomy Provides sensation to the anteromedial foot Equipment Betadine and alcohol wipes Sterile gloves 4x4 or 2x2’s Sterile towels 2-3 10 cc syringes with local anesthetic 25 gauge needle 1.5 inch needle 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! Local Anesthetic Choices 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 Positioning the foot Position the foot so you have access to all 5 nerves Blockade of the Deep Peroneal Nerve, Superficial Peroneal Nerve, and Saphenous Nerve can be blocked in one needle stick. 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 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 Deep Peroneal Nerve Block 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 Blocking the superficial peroneal nerve 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 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. Blocking the posterior tibial nerve 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 Blocking the sural nerve 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 Conclusion Easy to administer Effective anesthesia Often performed with much less local anesthetic than what textbooks advocate 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! 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. Metatarsal Block Metatarsals References Burkard J, Lee Olson R., Vacchiano CA. Regional Anesthesia. In Nurse Anesthesia 3 rd edition. Nagelhout, JJ & Zaglaniczny KL ed. Pages 977-1030. 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 6 th edtion. Miller, RD ed. Pages 16851715. Elsevier, Philadelphia, Penn. 2005. Wedel, D.J. & Horlocker, T.T. (2008). Peripheral nerve blocks. In D.E. Longnecker et al (eds) Anesthesiology. New York: McGraw-Hill Medical.