Single Versus Multiple Injections for Axillary Plexus Block

The study will be proposed to all patients undergoing formarm or hand surgery under axillary brachial plexus block. Patients will be randomized to one of two groups The first group - multiple injection group - will receive an ultrasound-guided axillary brachial plexus block with the traditional technique, i.e. multiple injections of local anesthetic in proximity to the 4 nerfs that innervate the arm. The arm will be abducted during the block procedure.

The second group - single injection group - will receive an ultrasound-guided axillary brachial plexus block with the arm placed behind the head and the elbow flexed. In this position the different nerfs group around the axillary artery where they will be blocked with a single injection of local anesthetic.

All patients will receive the same type and amount of local anesthetic: 30 ml of a mixture of ropivacaine 0.5 % + mepivacaine 1 %.

The primary outcome measure is the time needed for the performance of the block. Secondary outcomes are: success rate of the block at 30 minutes after the injection, needling time, time to first analgesic request, postoperative opioid consumption, pain scores at 12 and 24 hours postoperatively, block-related complications, and patient satisfaction. These outcomes are further defined in the section below.

Inclusion criteria

• Adult patients who undergo forearm or hand surgery under axillary brachial plexus block

Exclusion criteria

• History of allergic reaction to local anaesthetics
• Peripheral neuropathy
• Renal or hepatic insufficiency
• Coagulation disorders