Ultrasound-guided motor-sparing forearm blocks for hand surgery: surgical and anesthetic perspectives

INTRODUCTION: Certain specialized hand surgery procedures benefit from intraoperative motor testing and patient-demonstrated active range of motion. This requires motor-sparing regional anesthesia of the hand using targeted ultrasound-guided nerve blocks in the forearm. OBJECTIVE: We present a joint surgical and anesthetic perspective covering the utility and indications for motor-sparing forearm blocks. We describe the anatomical principles and technical details of their performance and discuss other considerations for surgical and anesthetic success. FINDINGS: Patient selection and expectation setting are critical for success. Four terminal nerves must be blocked: median nerve, ulnar nerve, superficial radial nerve, and lateral antebrachial cutaneous nerve. These must be targeted distal to origin of motor branches to extrinsic muscles of the hand, with precise deposition of limited volumes of local anesthetic. The nerves can be readily identified with ultrasound imaging by their predictable anatomical relationship to specific muscles and blood vessels. CONCLUSION: Intraoperative motor testing in complex surgical repair of the hand is associated with improved surgical outcomes, as well as greater patient satisfaction. Ultrasound-guided motor-sparing forearm blocks are a safe and effective method for achieving surgical anesthesia and optimal operating conditions in this context.