Ankle block Dr. S. Parthasarathy MD., DA., DNB, MD (Acu), Dip. Diab. DCA, Dip. Software statistics PhD (physio) Mahatma Gandhi Medical college and research institute, puducherry India

Indication Anaesthesia and postoperative analgesia of the foot. Patient Selection The ankle block is principally an infiltration block and does not require elicitation of paraesthesia. Thus, patient cooperation is not mandatory.

Anatomic Landmarks Five nerves supply the foot, four of which derive from the sciatic nerve (the tibial, the superficial and deep peroneal, the sural nerves) and one from the femoral nerve (the saphenous nerve).

Anatomy of ankle nerves

Posterior tibial nerve

Cross section

Area of innervations

Technique Generally, infiltration techniques are used for ankle blocks The posterior tibial nerve can be blocked by a nerve stimulator technique. All blocks are performed at the upper levels of the malleoli. patients should be adequately sedated during this block because it is primarily a “volume” block.

Patient Position The patient lies supine in neutral position or slight internal and then external rotation according to the nerve to be blocked Pillow to raise

SAPHENOUS NERVE BLOCK The saphenous nerve runs in the superficial fascia in front of the medial malleolus accompanying the saphenous vein and innervates the medial side of the foot. Technique For saphenous nerve block, 3 to 5 mL of local anesthetic is injected subcutaneously on either side of the saphenous vein at the superior aspect of the medial malleolus

Saphenous N block

TIBIAL NERVE BLOCK The tibial nerve lies under the flexor retinaculum at the midpoint between the medial malleolus and calcaneus A point is marked midway between the medial malleolus and calcaneus. If the posterior tibial artery is palpated, the needle is inserted just posterior to the pulse, following which 3–5 mL of local anesthetic is injected.

TIBIAL NERVE BLOCK Conversely, a 25-mm stimulating needle can be inserted at the skin mark and directed posterior to the tibial arterial pulse, looking for plantarflexion of the toes.

Tibial and sural nerves

The sural nerve located superficially between the lateral malleolus and the Achilles tendon. A 25- gauge, 3-cm needle is inserted lateral to the tendon and directed toward the malleolus as 5 to 10 mL of solution is injected subcutaneously

Peroneal nerves

DEEP PERONEAL NERVE BLOCK A needle is inserted perpendicular to skin just lateral to the extensor hallucis longus tendon to contact the tibia. It is then withdrawn a few millimeters and 3 mL of local anesthetic is injected.

SUPERFICIAL PERONEAL NERVE BLOCK Subcutaneous infiltration of 5 to 7 mL of local anaesthetic from the lateral to the medial malleolus.

Drugs motor blockade is not often needed, pt. can walk with analgesia Lower concentrations of local anesthetics may be used. Practical choices are 1% lidocaine, 1% mepivacaine, 0.25% to 0.5% bupivacaine, and 0.2% to 0.5% ropivacaine. Epinephrine ???, especially if injection is circumferential.

Anatomy and USG

Local injected

Deep peroneal nerve

Sural nerve

Complications Induration may cause difficulty Partial anaesthesia Pain with mutiple injections Infection Haematoma Nerve injury

Summary - ankle block Anaesthesia analgesia of foot Five nerves, 4 sciatic and one femoral Tibial, deep and sup. Peroneal, sural Saphenous Tibial and deep peroneal deeper (USG) Others superficial (normal technique) Technique Complications

We should know all blocks because we may need to anaesthetize such people

Thank you all