Ultrasound-guided block of selective branches of the brachial plexus for vascular access surgery in the forearm: a preliminary report.

Purpose: The operative field for vascular access (VA) surgery in the forearm is on the volar surface, and motor nerve block is not necessary for regional anesthesia. Therefore, selective block of branches of the brachial plexus may be a more efficient anesthesia technique.

Methods: Individual nerve blocks in the axillary brachial plexus and selective blocks of the musculocutaneous and medial antebrachial cutaneous nerves in the upper arm were performed using low doses and concentrations of a local anesthetic mixture of lidocaine and ropivacaine under ultrasound (US) guidance in patients undergoing VA surgery in the forearm. The targeted nerves were identified by continuous US tracing along the upper arm to the axilla in a short-axis view. We performed three VA surgeries in the forearm using an axillary brachial plexus block and four using a selective two-nerve bock in the upper arm. We recorded any additional anesthetic requirement and evaluated intraoperative pain using the Wong-Baker Faces Pain Rating Scale (WBFRS; 0 = no pain; 10 = worst pain).

Results: All of the target nerve branches were clearly identified by US tracing. All patients had satisfactory intraoperative pain control (0 or 2 score on WBFRS). Four patients required small additional doses of local anesthetic.

Conclusions: US-guided block of individual branches of the brachial plexus at the axilla achieved effective anesthesia using small amounts of local anesthetic. An advanced selective nerve block in the upper arm allows minimum necessary anesthesia and provides safe and efficient analgesia for VA surgery in the forearm.