Performing a block in the distal region of the brachial plexus, specifically below the clavicle, maximizes distal upper extremity anesthesia while minimizing phrenic nerve blockade. The classic blocks in this region include the infraclavicular block (ICB) in the chest wall above the axilla and the axillary block (AXB) on the medial aspect of the upper arm at the axilla. Unfortunately, these blocks historically have been difficult to perform for two reasons.
First, when performing a traditional ICB with the patient in the position of comfort (shoulder adducted, elbow flexed, and the fractured wrist resting at their side or on their chest/abdomen), the clavicle forces the operator to enter the skin at a very steep angle, significantly decreasing ultrasound visualization of the needle tip during the procedure and increasing the risk of iatrogenic pneumothorax. Second, in order to bring the brachial plexus out from under the clavicle, these blocks are commonly performed with significant upper extremity manipulation. Directly following an injury, abducting and externally rotating the shoulder is often not possible, limiting the generalizability of these infraclavicular approaches to the brachial plexus.
RAPTIR is a novel block that targets the same distal portion of the brachial plexus while correcting for the major challenges associated with traditional ICB and AXB. The patient is allowed to remain in the position of comfort during the procedure, and the needle angle is kept flat relative to the ultrasound probe, markedly increasing needle tip visualization and avoiding a trajectory deep into the thoracic cavity. Additionally, the needle path avoids the nearby cephalic vein and thoracoacromial artery, and only one injection is required to block the entire distal extremity.