Efficacy of Ultrasound-guided Axillary Nerve Block Versus Ultrasound-guided Peripheral Forearm Block in Patients Undergoing Hand Surgery

"To localize the median nerve, the ultrasound transducer will be placed in a transverse orientation proximally to the wrist cease at mid-forearm level, with a slight tilt distally towards the hand. An in-plane ultrasound-guided medial-to-lateral puncture will be made and 3ml of 2% lidocaine was injected within the fascia that envelopes the median nerve.~To perform the ulnar block, an ultrasound transducer will be placed in a transverse orientation over the ulnar side of the distal forearm. An in-plane ultrasound-guided medial-to-lateral or proximal-to distal puncture will be made and 3 ml of 2% lidocaine will be infiltrated into the fascial plane to block the ulnar nerve. Finally, we will apply a circumferential subcutaneous infiltration of 4 ml 2% lidocaine at the radial side of the wrist, 2cm proximal to the styloid process of the radius to block the terminal sensory branches of the radial, musculocutaneous, and medial antebrachial cutaneous nerves that may reach the palmar crease."

"The US probe will be applied in the axilla to obtain a short-axis view of the axillary artery. The following 4 nerves will be identified as hyperechoic structures: the median, ulnar, and radial nerve surrounding the axillary artery and the musculocutaneous nerve in the fascial layers between the biceps and coracobrachialis muscles.~A total volume of 20 mL lidocaine 2% will be administered divided over 4 locations. The needle is inserted in-plane from the anterior aspect of the axillary artery and directed toward the posterior aspect of the axillary artery to first anesthetize the radial nerve. The posteriorly located radial nerve is surrounded with 8 mL of local anesthetic. Afterward, the needle is withdrawn and redirected to the median and ulnar nerves, after which another 8 mL of local anesthetic is deposited. In the end, the needle is withdrawn and redirected toward the musculocutaneous nerve where another 4 mL of local anesthetic is deposited."