Sensorimotor Block Dynamics and Hemidiaphragmatic Palsy: Selective Trunk Block vs Supraclavicular Brachial Plexus Block

Patient will lie supine on the examination couch with the ipsilateral arm in the neutral position (adducted), neck slightly extended and the head turned slightly to the contralateral side. After local anesthetic (LA) infiltration (1-2 ml lidocaine 1%), the nerve block needle will be inserted and placed within the interscalene groove. Then, a 7 ml of a 1:1 mixture of lidocaine 2% with 1:200,000 epinephrine and levobupivacaine 0.5% will be slowly injected in aliquots. After that, the tip will be redirected lateral to the middle trunk. A further 8 ml of the LA mixture will be injected after which the nerve block needle will be completely withdrawn. The transducer will then be manipulated to a sub-omohyoid position. After LA infiltration, the nerve block needle is inserted in-plane until the needle tip is positioned close to and lateral to (9-12 o'clock position) the inferior trunk. A 10 ml of the LA mixture is injected in small aliquots and the needle will be removed after the injection.

Patient will lie supine on the examination couch with the ipsilateral arm in the neutral position (adducted), neck slightly extended and the head turned slightly to the contralateral side. Patient will receive a subcutaneous infiltration with 1-2 ml of 0.9% normal saline (NS) at the superior and middle trunk level after which the needle will be completely withdrawn. Then, a local anesthetic (LA) infiltration (1-2 ml lidocaine 1%) will then be performed at the supraclavicular fossa and the nerve block will be inserted in-plane to place the needle tip at the corner pocket. After that, 15-ml of a 1:1 mixture of lidocaine 2% with 1:200,000 epinephrine and levobupivacaine 0.5% will be slowly injected in aliquots. Once completed, the needle tip is gently withdrawn and redirected into the cluster formed by the divisions of brachial plexus. Then, the remaining 10-ml of the same LA mixture will be injected in small aliquots and the needle will be removed after the injection.